Which is the more powerful pump?

[rcpilot]

Hi all just picking your brains 2 pumps with flow rates of 3.8 and 5.7 which is the more powerful, also can you fit a commercial pump into a domestic system?

 

[ShaunCorbs]

5.7 is a higher flow rate but might be the same pressure as the 3.8

Need more info

 

[rcpilot]

what info would you need ?

 

[ShaunCorbs]

Are we taking heating or water and what’s the problem with the existing set up ?

 

[rcpilot]

Hi all well here is the problem in it's entirety, when we bought our house ( 2 bedroom ) up and down, the central heating was by way of a back boiler it had 3 radiators upstairs and 3 downstairs, but because of concrete floors downstairs, as it was previously council owned, the downstairs radiators were on what is known as dead legs. I put in a feature fireplace and ( as then you did not have to be gas safe ) I put a wall hung boiler in the bathroom and installed a fully pumped15mm pipe "Y" plan system which was open vented. The pump was a bog standard Grundfos one and as the boiler was getting long in the tooth I decided to get it replaced, in doing so I noticed that there was something wrong with the pump ie the body could be scraped with a knife and large chunks could be cut out of it so that was replaced with a new one. the chap who replaced the boiler put in a pressurised system. Not long afterwards I decided to take out the radiator in the bathroom and install a heated towel rail, now this was a big one, I noticed that the radiator in the entrance way was not getting hot at all but just left it . After a while I decided to get a Grundfos Alpha 2 L pump but it made no difference, so I then decided to get a Grundfos alpha 3b and take out the radiator in the sitting room and put in a big 2 panel one , for got to mention that I replaced all of the rads in the house with modern single panel ones the full length of the windows and put the bedroom ones on TRV's,. this is where everything went wrong, the Alpha 3b is setup and balanced using the 2 apps, Go Remote and Go Balance but these would not touch my system and could not balance it no matter what I did, I tried my best to manually balance the system, as I know how to, but that made no difference either, the entrance rad would not heat up the big one in the sitting room would not heat up the kitchen one would just get warm to the touch (these are all the rads on the dead legs) upstairs ones were getting quite warm, now I am left with the upstairs heating ok but nothing downstairs ( there are no air locks) I have come to the conclusion that the Alpha 3b is not powerful enough to pump the water round the system, I have spent quite a bit of time and money on pumps to try and rectify this problem but to no avail, so if any one out there knows of a powerful pump that can do the job drop me a line, one other thing I have come across is a Super 25 pump but it is a commercial one is there any reason why I cannot install it in my system obviously I would have to extend the port dimension as it is 180 mm not 130.

 

[ShaunCorbs]

a standard 15-60 eg ups2 or ups3 will be more than good enough for your system but it sounds like you have either a design issue or a blockage changing the pump
Won’t change much

 

[John.g]

The Alpha3 may display the head in meters, the flowrate in M3/hr and the power in watts, does it?.
What control mode are you running it on, CC (constant curve), CP (constant pressure) or PP (proportional pressure) ?.

 

[rcpilot]

a standard 15-60 eg ups2 or ups3 will be more than good enough for your system but it sounds like you have either a design issue or a blockage changing the pump
Won’t change much

Problem is it is the same design as before the only thing I have done is replaced the bathroom rad with a heated towel rail and replaced the flatpanel rad in the sitting room with a big double panel one, i know for certain that there is no blockage in the system because when I did the work I used the rad valves to get water down the dead legs on both sides of the rads before I connected then up.

 

[rcpilot]

The Alpha3 may display the head in meters, the flowrate in M3/hr and the power in watts, does it?.
What control mode are you running it on, CC (constant curve), CP (constant pressure) or PP (proportional pressure) ?.

yep head in meters and the flowrate in M3/hr and power in watts and it is on proportional pressure

 

[ShaunCorbs]

It’s not a pump problem as it’s very unlikely you have two bad pumps out the gate

You sure it’s not a one pipe system?

 

[John.g]

yep head in meters and the flowrate in M3/hr and power in watts and it is on proportional pressure

Give us the numbers then please , and the PP setting, should be a good indication of whats happening.

 

[John.g]

Hope its not on Auto Adapt, if running at ~ 9W then will pump nothing.

 

[rcpilot]

It’s not a pump problem as it’s very unlikely you have two bad pumps out the gate

You sure it’s not a one pipe system?

I'am not saying the pumps are bad, I am saying they are not powerful enough to pump the water round the system because of the dead legs, I am going to do an experiment tomorrow and will let you know the outcome

 

[ShaunCorbs]

Unless the dead legs are connected together which your system would never work these dead legs don’t matter as there just capped off services

 

[John.g]

I'am not saying the pumps are bad, I am saying they are not powerful enough to pump the water round the system because of the dead legs, I am going to do an experiment tomorrow and will let you know the outcome

Can you get any readings from the pump as it will reveal quite a lot IMO.

 

[Ben-gee]

Shaun OP is saying dead legs when what he actually means is drops.
This is a case of a little knowledge is a bad thing!

 

[ShaunCorbs]

Shaun OP is saying dead legs when what he actually means is drops.
This is a case of a little knowledge is a bad thing!

Agreed kinda guessed that also probably old back boiler with I’m guessing when removed flow and return linked hence why no flow to the rads as it’s talking the easiest route

 

[rcpilot]

Give us the numbers then please , and the PP setting, should be a good indication of whats happening.

Hi all well what I did was shut off all the upstairs rads so just the downstairs rad were open, set the pump to constant curve @100% operating mode @Max estimated head was 5.9 m and the speed was 5295.
The sitting room rad (which is the new big one) got hot but I could not balance it, the kitchen one which was cold or just barely warm was heating up but did not get hot, the entrance rad was still cold, my conclustion is either the pump cannot push the water round the system (all the above rads are on dead legs) or there is a blockage or trapped air in the return legs, which all I can do is bleed the return legs (not the rads) and see if it makes any difference, if it does not then the only solution is to find a much more powerful pump, if anyone can tell me what would happen if I fitted a commercial pump, of which I have the specs :- UP UPS 14m3/h 13m head pmax 10bar
UPS 25-80 :- 8.5m3/h 7mhead

 

[rcpilot]

Agreed kinda guessed that also probably old back boiler with I’m guessing when removed flow and return linked hence why no flow to the rads as it’s talking the easiest route

When I took out the back boiler I renewed the upstairs pipework to 15mm flow and return, the downstairs (as the boiler is upstairs) was put on dead legs or drops 15mm flow and return

 

[ShaunCorbs]

Do the test again but shut all but one rad eg one problem one does that get hot ?

 

[John.g]

Hi all well what I did was shut off all the upstairs rads so just the downstairs rad were open, set the pump to constant curve @100% operating mode @Max estimated head was 5.9 m and the speed was 5295.
The sitting room rad (which is the new big one) got hot but I could not balance it, the kitchen one which was cold or just barely warm was heating up but did not get hot, the entrance rad was still cold, my conclustion is either the pump cannot push the water round the system (all the above rads are on dead legs) or there is a blockage or trapped air in the return legs, which all I can do is bleed the return legs (not the rads) and see if it makes any difference, if it does not then the only solution is to find a much more powerful pump, if anyone can tell me what would happen if I fitted a commercial pump, of which I have the specs :- UP UPS 14m3/h 13m head pmax 10bar
UPS 25-80 :- 8.5m3/h 7mhead

You are pumping practically NIL as you can see from the pump curve that the flowrate at 5.9M is 0.
The pump power is 22/23kw, you should see this displayed and also the flowrate showing 0 M3/hr, so you might note these.
Also just shut the pump outlet valve for 10 secs or so with it running and the above numbers 5.9M/22kw/0.0M3/hr should remain the same.

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[rcpilot]

Do the test again but shut all but one rad eg one problem one does that get hot ?

Hi well interesting results:- I turned off the rad in the sitting room (which is 2400mm x 600mm double panel) and left the kitchen one open and left the entrance rad open, the entrance rad started to get hot, the kitchen started to get hotter than before so turned that one off and the entrance rad got hotter, which means to me there is no airlocks, here's some info on the pipe work the entrance is on 10mm pipework the kitchen is on 8mm pipe work, the sitting room is on 15mm pipe work. Being a disabled pensioner (72) I am at my time of life not able to rip out the dead legs and increase the size of the pipe work, I could shut off the kitchen rad as the kitchen is open to the sitting room so the sitting room rad would warm up the kitchen, I could also put TRV's on the bathroom towel rails as they can get pretty hot and the room stat is in the sitting room ( a data term box) which means that when the bedrooms and the bathroom reached the desired temp they would close down resulting in an increased flow to the down stairs dead legs but probably not enough to heat up all the downstairs rads. As I have always maintained the pumps I selected to run my system are not suitable ( silly me) what do you think about using one of the commercial pumps that I listed, i can vividly remember years ago I did put a big pump in the system ( i suppose I could find out which one but it would take me a long time) I even had to manufacture a plate with rubber mountings for the vibration noise and special connection hoses to the system) it worked ok, that's all I can say, anyone want to buy a Grundfos Alpha 3b 15 50/60 bought 4 months ago and has only just started to be used (no heating over the summer months)

 

[rcpilot]

You are pumping practically NIL as you can see from the pump curve that the flowrate at 5.9M is 0.
The pump power is 22/23kw, you should see this displayed and also the flowrate showing 0 M3/hr, so you might note these.
Also just shut the pump outlet valve for 10 secs or so with it running and the above numbers 5.9M/22kw/0.0M3/hr should remain the same.

 

[John.g]

Have a careful look at the pump power as iis possible that its pumping 0.65m3/hr (10.8LPM), if so the pump power will be 34W so carefully note this and then briefly shut the pump outlet valve and again note the power.

 

[rcpilot]

so what's the answer, if you mean change the settings how do you do it (if you have read my last reply you should understand)

 

[John.g]

Just note the pump power as above "Have a careful look at the pump power as its possible that its pumping 0.65m3/hr (10.8LPM), if so the pump power will be 34W so carefully note this and then briefly shut the pump outlet valve and again note the power.

Even if you installed a 10M pump the flowrate (if any) will only increase by 30% (sqroot 10/6) so maybe from 10.8LPM to 14.0LPM, so checkout the power please.

Also if you only now changed to 100% CC from PP3 then the flowrate would only have been 7.9LPM at 3.15M. assuming the pump is running at 34w above.

 

[rcpilot]

Hi John thanks for your input, I need to shut down (my head is spinning from all that's going on) so as I told you I am getting on a bit, would it be possible to give me the settings for the pump so as to obtain the measurements you require, then I will shut the outlet down and record the settings again and we can take it from there thanks.

 

[John.g]

OK, (I'm getting on a good bit more than you).

Just put or leave the pump in CC (constant curve) mode at 100% which is the highest possible setting that will give the greatest circulation.

Leave what ever rads you have open to the circuit now and just start the boiler/pump and note the pump head in (meters) M, the flowrate in M3/hr and the most important one of all the power output in (watts) W. and then just shut the pump outlet valve for say 5 secs (boiler/pump running) and just note the above readings again, re open the pump outlet valve and if desired then shut down the boiler/pump. You may wish to post the first set of readings before doing the closed valve test.

 

[Ben-gee]

I’m fairly sure this is a balancing problem.

 

[rcpilot]

OK, (I'm getting on a good bit more than you).

Just put or leave the pump in CC (constant curve) mode at 100% which is the highest possible setting that will give the greatest circulation.

Leave what ever rads you have open to the circuit now and just start the boiler/pump and note the pump head in (meters) M, the flowrate in M3/hr and the most important one of all the power output in (watts) W. and then just shut the pump outlet valve for say 5 secs (boiler/pump running) and just note the above readings again, re open the pump outlet valve and if desired then shut down the boiler/pump. You may wish to post the first set of readings before doing the closed valve test.

OK, (I'm getting on a good bit more than you).

Just put or leave the pump in CC (constant curve) mode at 100% which is the highest possible setting that will give the greatest circulation.

Leave what ever rads you have open to the circuit now and just start the boiler/pump and note the pump head in (meters) M, the flowrate in M3/hr and the most important one of all the power output in (watts) W. and then just shut the pump outlet valve for say 5 secs (boiler/pump running) and just note the above readings again, re open the pump outlet valve and if desired then shut down the boiler/pump. You may wish to post the first set of readings before doing the closed valve test.

Hi thanks John I get tired very easily these days with the problems associated with me being diabetic and problems with my knees and arms, I never thought that having arthritis in my arms would feel like I had bad toothache but it does with me been to the dentist and he pointed this out to me, will talk with you tomorrow if that is ok with you, got to get this sorted out before the cold weather sets in as this is another problem with being diabetic I cannot stand the cold, never mind.

 

[rcpilot]

Hi thanks John I get tired very easily these days with the problems associated with me being diabetic and problems with my knees and arms, I never thought that having arthritis in my arms would feel like I had bad toothache but it does with me been to the dentist and he pointed this out to me, will talk with you tomorrow if that is ok with you, got to get this sorted out before the cold weather sets in as this is another problem with being diabetic I cannot stand the cold, never mind.

 

[rcpilot]

Good morning John
Did like you said and the results from closing the outlet of the pump were no different than the previous results namely :- estimated pump head 5.9M, flow rate 0.0m3/h, power output 22watts

 

[John.g]

Just to be clear
Pump definitely in CC3 mode and results with the pump outlet open were the same as with it closed, above, ie, 5.9M, flow rate 0.0m3/h, power output 22watts??, extraordinary as you are getting some circulation through the rads.
Also check that the pump inlet valve is fully open.
Just confirm the above please and I will have another look through the pump manual

 

[John.g]

Have you still got the Alpha 2 pump?

 

[rcpilot]

Just to be clear
Pump definitely in CC3 mode and results with the pump outlet open were the same as with it closed, above, ie, 5.9M, flow rate 0.0m3/h, power output 22watts??, extraordinary as you are getting some circulation through the rads.
Also check that the pump inlet valve is fully open.
Just confirm the above please and I will have another look through the pump manual

Yes John exactly the same, I had the same query how come the downstairs big radiator (upstairs closed) was heating up with a flow rate of 0.0m3/h dos'nt seem possible, the system is a sealed fully pumped "Y" plan
one

 

[John.g]

Doesn't seem possible, can you change to constant pressure mode CP3 which is a constant 4.5M, if not pumping in this mode then the power will read only 15W.

I did come across here sometime where a pump was displaying all the above symptoms but when the head was removed it was full of soft sludge with the impeller vanes choked, vanes can be cleaned with a tie wrap.

If its still not pumping on CP3, I would be inclined to isolate the pump and remove its head (2 or 4 stud bolts) complete with impeller and inspect it, then flush pump body ports alernatively tfrom he inlet and outlet valves, you will have to top up the boiler afterwards.

OR, if you still have the Alpha 2, simply install that and see will it pump, why did you replace it with the Alpha 3 as it has exactly the same performance but not the same amount of bells and whistles
If this pump was installed originally then you can look at this first for any signs of sludge inside, etc.

 

[rcpilot]

Have you still got the Alpha 2 pump?

yes I have, another thing could my problems be associated with the outlet valve, why I say that is because the pump has the common connections on it but I have a gate valve just above it and I have been using that to close off the outlet and I have had problems with that type of gate valve before where the brass gate dose not fully open or fully close but sticks in one position.

 

[rcpilot]

Doesn't seem possible, can you change to constant pressure mode CP3 which is a constant 4.5M, if not pumping in this mode then the power will read only 15W.

I did come across here sometime where a pump was displaying all the above symptoms but when the head was removed it was full of soft sludge with the impeller vanes choked, vanes can be cleaned with a tie wrap.

If its still not pumping on CP3, I would be inclined to isolate the pump and remove its head (2 or 4 stud bolts) complete with impeller and inspect it, then flush pump body ports alernatively tfrom he inlet and outlet valves, you will have to top up the boiler afterwards.

OR, if you still have the Alpha 2, simply install that and see will it pump, why did you replace it with the Alpha 3 as it has exactly the same performance but not the same amount of bells and whistles
If this pump was installed originally then you can look at this first for any signs of sludge inside, etc.

Do you think that if I flushed out the whole system with a good cleaner it might do the trick?

 

[rcpilot]

Doesn't seem possible, can you change to constant pressure mode CP3 which is a constant 4.5M, if not pumping in this mode then the power will read only 15W.

I did come across here sometime where a pump was displaying all the above symptoms but when the head was removed it was full of soft sludge with the impeller vanes choked, vanes can be cleaned with a tie wrap.

If its still not pumping on CP3, I would be inclined to isolate the pump and remove its head (2 or 4 stud bolts) complete with impeller and inspect it, then flush pump body ports alernatively tfrom he inlet and outlet valves, you will have to top up the boiler afterwards.

OR, if you still have the Alpha 2, simply install that and see will it pump, why did you replace it with the Alpha 3 as it has exactly the same performance but not the same amount of bells and whistles
If this pump was installed originally then you can look at this first for any signs of sludge inside, etc.

i did notice you mentioned CP3, the pump was set in constant curve, so I reset it to CP3 closed the valve and the pump stopped, reopened it and the pump reset itself to constant curve, i have been using my wifes new phone but it keeps losing the connection with the pump and is very hard to reconnect

 

[John.g]

yes I have, another thing could my problems be associated with the outlet valve, why I say that is because the pump has the common connections on it but I have a gate valve just above it and I have been using that to close off the outlet and I have had problems with that type of gate valve before where the brass gate dose not fully open or fully close but sticks in one position.

Yes, a prime suspect, its quite possibly closed now so if the threads arn,t stripped you should get 3 to 5 full turns anticlockwise from it , there's always a 1/2 to 3/4 of free play before they start to open or close.

Do you think that if I flushed out the whole system with a good cleaner it might do the trick?

Only as a very last resort IMO, get the pump working and we can see then if required.

If you do get it opened then leave it as Don,t require any more closed valve readings

 

[rcpilot]

Yes, a prime suspect, its quite possibly closed now so if the threads arn,t stripped you should get 3 to 5 full turns anticlockwise from it , there's always a 1/2 to 3/4 of free play before they start to open or close.


Only as a very last resort IMO, get the pump working and we can see then if required.

If you do get it opened then leave it as Don,t require any more closed valve readings

Ok John I will strip the Alpha3 out check the gate valve, if it is ok I will put the Alpha 2 back in to see if that makes any difference, will get back to you when it's done could be a few days, one thing I forgot to tell you is I suffer from a back problem, when I was working as a service engineer for a firm that serviced and repaired lifts,hoists cranes etc I fell off an overhead crane over in Carlisle many years ago and I back pain when i do too much

 

[John.g]

Did you manage to open it, remove handwheel and use a adjustable spanner as a lever.

Maybe just renew the gate valve and take from there, you can always check pumps later as you can isolate them?

 

[rcpilot]

Did you manage to open it, remove handwheel and use a adjustable spanner as a lever.

Maybe just renew the gate valve and take from there, you can always check pumps later as you can isolate them?

Hi john well striped the Alpha 3 out and guess what, both valves were barely open so that was the restriction to flow, I renewed some of the pipe work to one of the radiators because it had a service valve on it and it was leaking and I am now cleaning up after the work, if everything is hunky dory with the system what is the best setting for the Alpha 3 and I might try to balance it with the go balance app.
Ken

 

[John.g]

That's good news Ken, I would set it to CC3 to start with, if you have to close all the rad valves individually (no u/staors/d/stairs zoning), then just run it as is, ie, if d/stairs only opened up now just start the pump and post the numbers, you can then open up the u/stairs and run both systems together on CC3 and have a look at those numbers.
Don't know what the total rad(s) output is but assuming 20kw max then the flowrate required will be 20LPM (1.2M3/hr) at a rad dT of 14/15C/kw which would result in a pump head of 4.7M in CC3 mode, see what you come up with anyway and you can decide on balancing, if any, is required later.

My system, 12 rads, 20kw, no balancing, works fine at a 3.5M head.

 

[rcpilot]

That's good news Ken, I would set it to CC3 to start with, if you have to close all the rad valves individually (no u/staors/d/stairs zoning), then just run it as is, ie, if d/stairs only opened up now just start the pump and post the numbers, you can then open up the u/stairs and run both systems together on CC3 and have a look at those numbers.
Don't know what the total rad(s) output is but assuming 20kw max then the flowrate required will be 20LPM (1.2M3/hr) at a rad dT of 14/15C/kw which would result in a pump head of 4.7M in CC3 mode, see what you come up with anyway and you can decide on balancing, if any, is required later.

My system, 12 rads, 20kw, no balancing, works fine at a 3.5M head.

I have bled all the rads but left the kitchen one out of it for the time being, the bathroom towel rails are getting mad hot and the sitting room is starting to heat up, nothing yet in the bedrooms but I suppose balancing will bring them up

 

[John.g]

With CC3?
What pump values are you getting?

 

[John.g]

You said in post #1 that the upstairs rads were heating but not downstairs?,
If you have a Y system with a mid position valve then just carry out the basic check that the pump arrow is pointing towards it, also ensure that system is pressurized to 1.3/1.5 bar.
Can you also take pump values with DHW heating only on, then with (eventually) DHW+d/Stairs+U/stairs.

 

[rcpilot]

You said in post #1 that the upstairs rads were heating but not downstairs?,
If you have a Y system with a mid position valve then just carry out the basic check that the pump arrow is pointing towards it, also ensure that system is pressurized to 1.3/1.5 bar.
Can you also take pump values with DHW heating only on, then with (eventually) DHW+d/Stairs+U/stairs.

Hi John, this flaming thing has got me demented, when I put everything back together, filled the system, bled the radiators, then started it up it was showing 24 watts on the pump and I think 0.6m3/h and the towel rads were getting mad hot the big rad downstairs was getting hot, both bedrooms were cold obviously because the lockshields were closed, the entrance rad was still cold, so I turned it off. Today I turned it back on and got the same results, so I started to manually balance the towel rails got them somewhere near the 12 deg difference checked the pump and the wattage had gone down to 15 and the m3/h was showing 0.0, hair now all over the floor.

 

[rcpilot]

Hi John, this flaming thing has got me demented, when I put everything back together, filled the system, bled the radiators, then started it up it was showing 24 watts on the pump and I think 0.6m3/h and the towel rads were getting mad hot the big rad downstairs was getting hot, both bedrooms were cold obviously because the lockshields were closed, the entrance rad was still cold, so I turned it off. Today I turned it back on and got the same results, so I started to manually balance the towel rails got them somewhere near the 12 deg difference checked the pump and the wattage had gone down to 15 and the m3/h was showing 0.0, hair now all over the floor.

Hi John decided to check the pump with the "go remote app" that pump has got a mind of it's own it reset itself from CC to CP so I reset it to CC and operating @ max it went back to showing 24 watts but the flow rate remained @ 0.0m3/h

 

[John.g]

Balancing should be the last thing to do IMO.
Can you just run on DHW and check values as this is practically a short circuit through the cylinder coil where most of the short? run will/should be in 22mm, if there is a balancing gate valve on the coil return, just open it fully.
I would expect to see ~ 34W on CC3.

 

[rcpilot]

Balancing should be the last thing to do IMO.
Can you just run on DHW and check values as this is practically a short circuit through the cylinder coil where most of the short? run will/should be in 22mm, if there is a balancing gate valve on the coil return, just open it fully.
I would expect to see ~ 34W on CC3.

I will call for hot water as the( data term) will allow me to press for one shot hot water the "Y" plan valve should close the heating down and open the hot water circuit up, if that does not work are the Alpha 3 and the Alpha 2 exactly the same apart from the control panel if so Instead of going down the road of taking the Alpha 3 out I could just change the heads and see what that does

 

[rcpilot]

Balancing should be the last thing to do IMO.
Can you just run on DHW and check values as this is practically a short circuit through the cylinder coil where most of the short? run will/should be in 22mm, if there is a balancing gate valve on the coil return, just open it fully.
I would expect to see ~ 34W on CC3.

Hi John I called for hot water and it immediately went up to 34 watts and the flow rate went up to 0.6m3/h

 

[rcpilot]

Hi John I called for hot water and it immediately went up to 34 watts and the flow rate went up to 0.6m3/h

So when the hot water reached it's temperature the "Y" plan valve closed the hot water circuit and opened the rad circuit the wattage went back to 15 flowrate 0.0m3/h, so I opened the lockshield valves on the towel rails and the wattage went back up to 34watts and the flow rate up to 0.6m3/h what would take that to mean?

 

[John.g]

Hi John I called for hot water and it immediately went up to 34 watts and the flow rate went up to 0.6m3/h

That points to something else rather than a pump problem, once the pump reaches max power then it will only display 0.6M3/hr, but it could be pumping 1M3/hr @ 5M or 1.5M3/hr @ 4M and so on depending on pipe/coil friction losses.

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[John.g]

So when the hot water reached it's temperature the "Y" plan valve closed the hot water circuit and opened the rad circuit the wattage went back to 15 flowrate 0.0m3/h, so I opened the lockshield valves on the towel rails and the wattage went back up to 34watts and the flow rate up to 0.6m3/h what would take that to mean?

It would mean that there is no real restrictions in the upstairs pipe work.
Can you ensure all d/stair rad valves including lockshields are fully open, then shut all upstairs (one valve on each rad will do) then take pump values on d/stairs only.

 

[rcpilot]

It would mean that there is no real restrictions in the upstairs pipe work.
Can you ensure all d/stair rad valves including lockshields are fully open, then shut all upstairs (one valve on each rad will do) then take pump values on d/stairs only.

ok will do

 

[rcpilot]

ok will do

Right opened all the rads downstairs no change, still 34 watts, closed off both bedrooms again no change still 34watts, but as soon as I touched the towel rails the wattage went down to 16 flowrate 0.0m3/h, any suggestions?

 

[rcpilot]

Right opened all the rads downstairs no change, still 34 watts, closed off both bedrooms again no change still 34watts, but as soon as I touched the towel rails the wattage went down to 16 flowrate 0.0m3/h, any suggestions?

the wattage is back up to 22 watts but the flow rate remains at 0.0m3/h

 

[rcpilot]

the wattage is back up to 22 watts but the flow rate remains at 0.0m3/h

Hi john just been looking at the dates I bought the towel rails and the Alpha 3:- bought the rails on the 23/6/2021, I can remember I had problems when I plumbed them in so finished the job (after set backs of one sort or another) 2 months later, bought the Alpha 3 on the 27/4/2022 but that was after we had been away on holiday, so between finishing the rail installs and noticing that the heating was'nt working as well was about 4 months, everything seems to stem from when I put in the towel rails, just wondered if I have done something wrong will have to check to find out but we are going away again in our caravan so probably won't do that until we come back, what do you think? open to suggestions, or a slap on the wrists!

 

[John.g]

Right opened all the rads downstairs no change, still 34 watts, closed off both bedrooms again no change still 34watts, but as soon as I touched the towel rails the wattage went down to 16 flowrate 0.0m3/h, any suggestions?

So, how many rads open d/stairs when all u/stairs rads + towel rads shut off when flow fell to zero??.
If you reopen just one towel rad does the flow increase?
Normally, even if only one rad open fully would expect a flowrate of - 0.3 m3/hrs and a pump power of - 25/26W on CC3.

 

[rcpilot]

So, how many rads open d/stairs when all u/stairs rads + towel rads shut off when flow fell to zero??.
If you reopen just one towel rad does the flow increase?
Normally, even if only one rad open fully would expect a flowrate of - 0.3 m3/hrs and a pump power of - 25/26W on CC3.

Hi john there are 3 rads downstairs each one on it's own drop, when I shut off the bedroom rads there was no change to the wattage :- 34 and no change to the flow :- 0.6m3/h ( both valves on each towel rail were fully open) as soon as I touched either the lockshield or the on/off valve on either towel rail the wattage went down to 22 watts and the flow went down to 0.0 m3/h it's got me thinking that there is a problem with the pipework to or from the towel rails, if I have to alter the pipe work I can get at the flow from the "Y" plan valve and increase it to 22mm (it's 15mm at the present) and take it all the way into the bedroom to where the first drop is to the big rad in the sitting room then it would be 15mm after that as I cannot get at access after that

 

[rcpilot]

Hi john there are 3 rads downstairs each one on it's own drop, when I shut off the bedroom rads there was no change to the wattage :- 34 and no change to the flow :- 0.6m3/h ( both valves on each towel rail were fully open) as soon as I touched either the lockshield or the on/off valve on either towel rail the wattage went down to 22 watts and the flow went down to 0.0 m3/h it's got me thinking that there is a problem with the pipework to or from the towel rails, if I have to alter the pipe work I can get at the flow from the "Y" plan valve and increase it to 22mm (it's 15mm at the present) and take it all the way into the bedroom to where the first drop is to the big rad in the sitting room then it would be 15mm after that as I cannot get at access after that

I was just thinking that as the towel rails were fully open, and the bedroom rads closed and there was no change to the figures, as soon as I touched either valve on the towel rails I was virtually shutting off the flow because the pump cannot pump down the drops and back up again to the boiler, I don't know I might be clutching at straws

 

[John.g]

Looks that way alright, you my have both towel rads in series and the return tied back into the flow, a one pipe system in effect, if you run them again with both opened and the 3 d/stairs opened as well then the flow temperature into the 3 rad may be just lukewarm as it will/could be now the return temperature from both Towel rads?.

 

[rcpilot]

Looks that way alright, you my have both towel rads in series and the return tied back into the flow, a one pipe system in effect, if you run them again with both opened and the 3 d/stairs opened as well then the flow temperature into the 3 rad may be just lukewarm as it will/could be now the return temperature from both Towel rads?.

Hi John I have a few jobs to do to be able to lift part of the bathroom floor up again but as soon as I have had a chance I will get back to you with the outcome.

 

[rcpilot]

Hi John I have a few jobs to do to be able to lift part of the bathroom floor up again but as soon as I have had a chance I will get back to you with the outcome.

One thing John would 15mm piping have the same effect if so I am going to try and get most of the accessible runs redone in 22mm pipe and see if that improves the matter, will have to live in our caravan on the drive till I get it done.

 

[John.g]

15mm piping would require - 4.5 M head IMO to circulate 20LPM assuming total rad output of 20kw, if main pipework is 22Mm then a 2.5M head would probably suffice so see what the piping problem is first and you can decide then maybe to renew some sectios in 22mm but the 15mm is certainly not the cause of your present problem

 

[rcpilot]

15mm piping would require - 4.5 M head IMO to circulate 20LPM assuming total rad output of 20kw, if main pipework is 22Mm then a 2.5M head would probably suffice so see what the piping problem is first and you can decide then maybe to renew some sectios in 22mm but the 15mm is certainly not the cause of your present problem

Hi John, notice the time, I cannot sleep I am thinking constantly about this problem, thought of this, once I have checked the pipework for the 2 towel rails in the bathroom (that is where the problem lies I think) and done the necessary work, if I disconnect the heating pipe from the "Y" plan valve, blanked the valve off and put a drain hose on the heating pipe, isolated the pump so no water can come through the pump, the only way water can get into the boiler is through the filling loop, as the "Y" plan valve is blanked off no water can back flow through the hot water tank. If I then shut off all the flow valves on all the rads turn on the filling loop the boiler will fill up and the only way water can get to each rad is through the boiler via the return pipe, as all the flow valves are shut off the return pipe on each rad is now acting as a flow agreed so far? Now if I open the flow valve on the rad furthest from the boiler the water will flow through that rad and out of the drain hose I connected to the heating pipe I disconnected from the "Y" plan valve thus flushing out that rad and section of the heating system. If I then shut off that flow valve on that rad and opened the flow valve on the next furthest rad away from the boiler it will do the same as before. I can now do exactly the same for each rad until I get back to the nearest rad to the boiler, this will I hope ensure that there is no restriction in the pipework and also flushing the system out. If I then close the filling loop the pressure in the system should return to "0" as the drain pipe is still connected, if I disconnect the drain from the heating pipe the system should be filled to the height of the "Y" plan valve, so from that I can say that the downstairs would be filled and the upstairs filled to the height of the valve ie halfway up each upstairs rads, would you agree so far? I then reconnect the heating pipe to the "Y" plan valve and begin to fill up the system via the filling loop as all the rads are still shut off and the nearest rad to the boiler is open any air can only go to that rad so I vent it and then open up all the rads and fill them, having done all that the pump, as there should be no restrictions in the pipework, should be able to pump water through the whole system, if it cannot then I can assume the pump is not strong enough or I can put a stick of dynamite in the boiler and blow the whole thing to kingdom come I am that "P £ $ % & D off with the whole situation and go and live in our caravan in the back garden. I am ever so sorry for boring the pants off you and thank you very much for all the help you have given me, all the best Ken

 

[John.g]

I'll have a look at the above later on but you can see if pipework, (at least the main d/stairs flow/return) is free if you do the following before addressing the towel rad problems.

Shut off the upstairs, ensure all downstairs rads open fully, run the pump in the following 3 modes, CC3, CP1, CP2 &CP3 and note the pump values, then do the same tests with the two towel rads only and post your results, it will only take a few minutes to do these tests.

Also, please post the outputs (kw) or dimensions of the rads, including towel rads and their locations.

The main job is to fix your pipework and everything else can be decided then.

Edit, 3 modes are CC3, CP2 and CP3.

 

[John.g]

This might put your mind a bit more at ease until you actually see what's what.

I am assuming that there are two rads in series and in series then with the flow or return main piping, you would then have 4 very small valves in series which are designed only for flowrates sufficient for say a 3 kw rad, you can see below that the head loss is only 0.65M with a 3kw rad or 1.8M in the very unlikely event that you have a 5kw rad. With 2 rads in series the head loss is 3.6M @ 5kw/5LPM so if installed in the main flow/return then nothing left for pipeline losses etc.?.

So get your floor up ASAP.

You don't have permission to view attachments. Attachments are hidden.

 

[rcpilot]

This might put your mind a bit more at ease until you actually see what's what.

I am assuming that there are two rads in series and in series then with the flow or return main piping, you would then have 4 very small valves in series which are designed only for flowrates sufficient for say a 3 kw rad, you can see below that the head loss is only 0.65M with a 3kw rad or 1.8M in the very unlikely event that you have a 5kw rad. With 2 rads in series the head loss is 3.6M @ 5kw/5LPM so if installed in the main flow/return then nothing left for pipeline losses etc.?.

So get your floor up ASAP.

You don't have permission to view attachments. Attachments are hidden.

Hi john have checked all the pipework and everything seems to be ok in theory, there could be a "bit of a traffic jam" where the returns go back to the boiler but the only way I could alleviate that would be to incorporate swept "T"s in the return lines from the towel rails,

 

[rcpilot]

Hi John I have been a bit busy today but will do the tests tomorrow and get the results off to you also the kw of each of the rads

 

[John.g]

Hi John I have been a bit busy today but will do the tests tomorrow and get the results off to you also the kw of each of the rads

Very good, thanks.

Hi john have checked all the pipework and everything seems to be ok in theory, there could be a "bit of a traffic jam" where the returns go back to the boiler but the only way I could alleviate that would be to incorporate swept "T"s in the return lines from the towel rails,

The plot thickens!

Hi john there are 3 rads downstairs each one on it's own drop, when I shut off the bedroom rads there was no change to the wattage :- 34 and no change to the flow :- 0.6m3/h ( both valves on each towel rail were fully open) as soon as I touched either the lockshield or the on/off valve on either towel rail the wattage went down to 22 watts and the flow went down to 0.0 m3/h it's got me thinking that there is a problem with the pipework to or from the towel rails, if I have to alter the pipe work I can get at the flow from the "Y" plan valve and increase it to 22mm (it's 15mm at the present) and take it all the way into the bedroom to where the first drop is to the big rad in the sitting room then it would be 15mm after that as I cannot get at access after that

Can you verify/clarify the above.

With bedroom, Upstairs?,rads shut off, you get 34W/0.6m3/hr through the Towel rads + (maybe) the downstairs rads but if you close any one of the towel rads then 22W/0.0m3/hr.

Can or have you tried shutting the downstairs rads, opening the bedroom rads + the towel rads and note the values.
Then shut shut the towel rad(s) valves and note the values, ie with the bedroom rads only open.

Also can you see/show where the expansion vessel is tied in to the system.

A simple line diagram might show up something.

 

[rcpilot]

Very good, thanks.

The plot thickens!

Can you verify/clarify the above.

With bedroom, Upstairs?,rads shut off, you get 34W/0.6m3/hr through the Towel rads + (maybe) the downstairs rads but if you close any one of the towel rads then 22W/0.0m3/hr.

Can or have you tried shutting the downstairs rads, opening the bedroom rads + the towel rads and note the values.
Then shut shut the towel rad(s) valves and note the values, ie with the bedroom rads only open.

Also can you see/show where the expansion vessel is tied in to the system.

A simple line diagram might show up something.

Hi John I have made a line drawing of how the towel rails are plumbed into the system as you can see theoretically it is ok, where I have ringed the drawing could possibly be a "traffic jam back to the boiler" and as I said the only way to alleviate the problem would be to replace the "T" pieces with swept "T"s ?

You don't have permission to view attachments. Attachments are hidden.

 

[John.g]

Changing the Tees would make no difference IMO.
If you shut off the towel rad or rads does the front bedroom still heat up? and the other 2? bedrooms and what are the pump values?.

 

[rcpilot]

I'll have a look at the above later on but you can see if pipework, (at least the main d/stairs flow/return) is free if you do the following before addressing the towel rad problems.

Shut off the upstairs, ensure all downstairs rads open fully, run the pump in the following 3 modes, CC3, CP1, CP2 &CP3 and note the pump values, then do the same tests with the two towel rads only and post your results, it will only take a few minutes to do these tests.

Also, please post the outputs (kw) or dimensions of the rads, including towel rads and their locations.mm

The main job is to fix your pipework and everything else can be decided then.

Edit, 3 modes are CC3, CP2 and CP3.

Hi John here are the rad output wattages :- towel rail 1700 x 700mm 668w bathroom
towel rail 600 x 550mm 221w bathroom
flat panel 1800 x 500mm 752w front bedroom
flat panel 1500 x 500mm 626w back bedroom
flat panel 1100 x 500mm 459w entrance
flat panel 1100 x500 mm 459w kitchen
double panel 2400 x 600mm 4485w
the position on the system is as follows :- small towel rail 1
large towel rail 2
kitchen 3 :- on drop
entrance 4 :- on drop
front bedroom 5
back bedroom 6
sitting room 7 :- on drop

when the system was an open vented one it had the vent running up into the loft back to the filling tank, when the plumber put in the new boiler he cut the vent in the loft and attached the expansion vessel to it, pump values to come.

 

[John.g]

What is the expansion vessel pressure and where is it displayed?, is there any pressure display on the boiler.
Does that converted vent go back to the boiler?.

Those rad outputs are incorrect in some cases a 1100X500 rad output is 1265watts and a 1500X500 is 1568watts, a 1700x700 would be roughly 2000watts.
I can figure most of them out anyhow, do they include all the house rads?.

 

[John.g]

I get a total rad output of 12435W but you seem to have omitted the dining room, if you assume another double 2400X600 rad , 4485W, then the total is 16920W or say 17kw, no problem for a alpha3 as the circulation flow required is 24.4LPM @ a 10C dT and 16.2LPM @ a 15C dT. which equals pump heads of 4.2m & 5.2M respectively on CC3.

 

[rcpilot]

What is the expansion vessel pressure and where is it displayed?, is there any pressure display on the boiler.
Does that converted vent go back to the boiler?.

Those rad outputs are incorrect in some cases a 1100X500 rad output is 1265watts and a 1500X500 is 1568watts, a 1700x700 would be roughly 2000watts.
I can figure most of them out anyhow, do they include all the house rads?.

the rad outputs are as stated the outputs that you have given does relate to the values I have not watts but btu's, I take it that the expansion vessel is the red tank that is connected to the mains to fill the system, I got where it was connected wrong the vent was in fact capped off and it was connected to the feed from the filler tank, the pressure that that is showing is about 1 bar and is on a gauge on the top of the vessel there is no pressure gauge on the boiler and that is all the rads in the house.

 

[John.g]

The values I have given are in watts, to convert to Btu, X 3.412, ie a 1800X500 single is 1881watts (you have 752W) or 6,418Btu, anyhow your total output as you have included all the rads is 12,435watts or 12.44kw so even less of a problem as the flowrates respectively now for 10C & 15C dTs are 17.83LPM & 11.89LPM.

Can you just post a photo of that E.vessel and also showing where its connected into the system, you say it is connected into the cold feed from the filler (feed & expansion) tank, so this tank is now redundant?.

OK, can you just clear this up once and for all .

If all the rads are opened up, including the towel rads, what rads heat up? (also pump values0
If all the rads are opened up, and you shut off one Towel rad , what rads now heat up? (also pump values0
If all the rads are opened up, and you close off two Towel rads, what rads now heat up? (also pump values)

 

[rcpilot]

The values I have given are in watts, to convert to Btu, X 3.412, ie a 1800X500 single is 1881watts (you have 752W) or 6,418Btu, anyhow your total output as you have included all the rads is 12,435watts or 12.44kw so even less of a problem as the flowrates respectively now for 10C & 15C dTs are 17.83LPM & 11.89LPM.

Can you just post a photo of that E.vessel and also showing where its connected into the system, you say it is connected into the cold feed from the filler (feed & expansion) tank, so this tank is now redundant?.

OK, can you just clear this up once and for all .

If all the rads are opened up, including the towel rads, what rads heat up? (also pump values0
If all the rads are opened up, and you shut off one Towel rad , what rads now heat up? (also pump values0
If all the rads are opened up, and you close off two Towel rads, what rads now heat up? (also pump values)

in the old system ie open vented "Y" plan, the old boiler (Ferroli Roma which I put in many years ago) was fed from a small open tank in the loft and a vent from the flow went up the wall and was positioned over this small tank (this tank was removed when the new Worcester 15 Ri was put in) the old vent was cut off and capped. The old cold feed to the old boiler was cut in the loft and the expansion vessel connected to it, the expansion vessel was connected to a mains feed of 15mm dia via a pressure gauge. If all the rads and the towel rails are fully opened pump values are 34w and 0.6 m3/h and towel rads are hot, back bedroom hot, front bedroom luke warm, entrance cold, sitting room cold, kitchen just off cold. Shut off small towel rad large towel rad still hot, back bedroom hot,front bedroom flow pipe hot but rad is luke warm, entrance still cold, sitting room flow pipe hot but rad dosn't seem to be getting hot, kitchen flow pipe hot rad just off cold pump values 32w and 0.4m3/h. With both towel rails shut off the pump values are 22w and the m3/h gradually drops to 0.0m3/h . Both bedroom rads are warming up, entrance is still cold, sitting room and kitchen starting to warm up.I was wondering if there was a problem with the pump reason being I have to keep on reinstalling go remote to change the settings, also are the Alpha 3 and the Alpha2 exactly the same pump apart from how the Alpha 3 is adjusted and setup if so I was thinking of removing the head from the Alpha 3 and replacing it with the head from the Alpha 2 to see if that made any difference

 

[John.g]

It's amazing how the flow drops off with both T.rads shut, would wonder if any problem with system pressure...EV pipe blockage etc but as system was refilled using this then? You might just increase pressure by topping up to 1.5bar.
The pumps appear to be the same so probably OK to swap heads, but as you can easily isolate maybe easier to swap whole pump?

 

[rcpilot]

It's amazing how the flow drops off with both T.rads shut, would wonder if any problem with system pressure...EV pipe blockage etc but as system was refilled using this then? You might just increase pressure by topping up to 1.5bar.
The pumps appear to be the same so probably OK to swap heads, but as you can easily isolate maybe easier to swap whole pump?

what would be the max pressure I could use on this system/ easier for me to just unbolt 4 bolts and swap heads

 

[John.g]

The boiler PRV lifts at 3bar so wouldn't,t pressurised to move than 1.5/1.7 to avoid lifting it when system heats up. Changing pump heads only gives you a opportunity to inspect impellers for sludge build up.

 

[rcpilot]

The boiler PRV lifts at 3bar so wouldn't,t pressurised to move than 1.5/1.7 to avoid lifting it when system heats up. Changing pump heads only gives you a opportunity to inspect impellers for sludge build up.

Hi john the system used to heat up no bother with the old bathroom rad and the smaller sitting room rad so I have eliminated both of them by closing them off, if the problem was with those two items then the system should now heat up with no problems unless there is an airlock somewhere and the only way I would be able to say for definite would be to carry out flushing the system section by section, if no airlock was present then the only solution is the Alpha 3 is not doing what it is supposed to do, I can change the heads but I would not be able to say the Alpha 2 was in a working condition, but if the system heated up then it's proof the Alpha 3 is cattle trucked agreed?

 

[John.g]

Yes, go for that, should be a simple task, back flush from both sides when pump head removed but keep system topped up and to 1.5bar finally.

 

[rcpilot]

Yes, go for that, should be a simple task, back flush from both sides when pump head removed but keep system topped up and to 1.5bar finally.

will let you know how I get on

 

[rcpilot]

will let you know how I get on

I removed the heads from both of the pumps and the size of the impellers are totally different, the Alpha 3 is only 38mm in dia where as the Alpha 2 is 63mm in dia so I am going to have to swap over the whole pumps

 

[rcpilot]

I removed the heads from both of the pumps and the size of the impellers are totally different, the Alpha 3 is only 38mm in dia where as the Alpha 2 is 63mm in dia so I am going to have to swap over the whole pumps

Hi John I changed the pumps over and put the Alpha 2 on it's highest setting, there was no difference which makes me think (as I have not done the flushing yet) there is a blockage in the pipe line, I put my thinking cap on and came up with this, the picture that is in the attachments of the towel rail plumbing, as the towel rails were off, the system was acting as before so I opened the small towel rail and it started to get hot in no time at all, so I concluded that the flow and return for that towel rail was ok, the same applies to the large towel rail, but when I turn the towel rails off the system goes back to where it was before so I am thinking the blockage could be where the return from the front bedroom meets the return to the boiler any ideas?

 

[Ben-gee]

Investigate that area of pipework with a magnet, if it’s attracted then chances are it’s full of steel based sludge.

 

[rcpilot]

Hi John I changed the pumps over and put the Alpha 2 on it's highest setting, there was no difference which makes me think (as I have not done the flushing yet) there is a blockage in the pipe line, I put my thinking cap on and came up with this, the picture that is in the attachments of the towel rail plumbing, as the towel rails were off, the system was acting as before so I opened the small towel rail and it started to get hot in no time at all, so I concluded that the flow and return for that towel rail was ok, the same applies to the large towel rail, but when I turn the towel rails off the system goes back to where it was before so I am thinking the blockage could be where the return from the front bedroom meets the return to the boiler any ideas?

Hi John, well I cut out the "T" piece I thought might be the problem but it was ok , what was left now was an open return that was connected to that "T" so I connected a drain pipe to it, one end that was open that went to a towel rail I blanked that off, the other open end went to the boiler so I blanked that end off so I started to flush the system using the filler - expansion tank as the flow the water went through the boiler past the "Y" plan valve and into the flow pipe opened up each rad in turn and got a flow in was not very strong in fact I could stop it by putting a finger on the end of the return drain pipe, I flushed out each section in turn by opening and closing the return valves on each rad, got exactly the same flow through each section, I am going to try and put mains water pressure through the flow, by eliminating the expansion tank, boiler and "Y" plan valve and should get mains pressure back out of the return drain pipe if I do then it is as I said at the start the pumps that I have are not strong enough for my system or they are both knackered which means I need a stronger pump any ideas on these :- Britherm SL 25-80/180, Brithem super 25-120/180, Britherm Pro 2580/180, yes I know the port to port is 180 mm but that is easily overcome.

 

[John.g]

Sorry for late reply, didn't get any email notification(s) of your posts.
Will read the above in more detail later.

You have a sealed system so you will have the same pressure throughout the system and it will be at the EV pressure (with allowance for elevation) so if you were to attach a pressure gauge to any part of the system then you should get 1 to 1.5bar?? pressure, makes me wonder (again) where it joins the system exactly. Unless the system is 100% blocked in places then you should feel that pressure if you hold your finger over any point of opening, if there is a blockage then yes the flow will reduce to a trickle once you remove your finger.
When you were testing/flushing, how did you keep the EV pressure at 1/1.5bar?. also whether flushing with the EV or mains, ( not a bad idea), ensure the 3 port valve is, preferably latched in CH position but if not, latch it in mid position.

I would be very surprised if any one of those two pumps is knackered, if the impellers/pump ports are clear and you are getting the power associated with the mode settings and flows, and you were, then nothing wrong there IMO.

Where does the EV outlet join the system, is it before the pump?, you might remove it where it joins the system and ensure clear.

 

[rcpilot]

Sorry for late reply, didn't get any email notification(s) of your posts.
Will read the above in more detail later.

You have a sealed system so you will have the same pressure throughout the system and it will be at the EV pressure (with allowance for elevation) so if you were to attach a pressure gauge to any part of the system then you should get 1 to 1.5bar?? pressure, makes me wonder (again) where it joins the system exactly. Unless the system is 100% blocked in places then you should feel that pressure if you hold your finger over any point of opening, if there is a blockage then yes the flow will reduce to a trickle once you remove your finger.
When you were testing/flushing, how did you keep the EV pressure at 1/1.5bar?. also whether flushing with the EV or mains, ( not a bad idea), ensure the 3 port valve is, preferably latched in CH position but if not, latch it in mid position.

I would be very surprised if any one of those two pumps is knackered, if the impellers/pump ports are clear and you are getting the power associated with the mode settings and flows, and you were, then nothing wrong there IMO.

Where does the EV outlet join the system, is it before the pump?, you might remove it where it joins the system and ensure clear.

Hi john thanks for the reply, lets start from the beginning, I bought the Alpha 2 a few years ago when I found out there was something wrong with the basic Grundfos pump, after it was fitted it was working ok, then aprox 5 years ago we replaced the old boiler with the Worcester 15 Ri again everything was fine until last year when I put in the heated towel rails, I then thought that there was something wrong with the Alpha 2 pump so I bought the Alpha 3 but that did not solve the problem, as we have tested the system thoroughly and by eliminating the towel rails the system should have heated up the same as the towel rails but it did not, I think buying a new pump at this stage is not the answer because if the system was clear the Alpha 3 should have maintained 34w and 0.6m3/h at least but it did not it went back to 22w and 0.0m3/h and the system barely got warm, so I am thinking there is a partial blockage somewhere and I think, but I could be wrong, that it is in either the flow or return between the towel rails and the first real radiator which is the kitchen because if it was past the kitchen or for that matter before the front bedroom, the kitchen rad should have got hot and the entrance but they do not, the entrance does not heat up at all, so I am going to rod the flow and return and see what happens, if they are clear then I think it is a new pump

 

[John.g]

Can you just do up another line diagram just on that circuit including the rads, pump, 3 way valve & expansion vessel etc.
If the lines are clear then I would be almost 100% sure that a higher head pump will not sort the problem, we know (proved) that the Alpha 3 has a 6.4M head available and pumps 0.6m3/hr at this head, a 8M pump would increase the 0.6m3/hr flow to 0.67m3/hr and a 10M pump will increase the flow from 0.6m3/hr to 0.75m3/hr but neither can increase or get anything to flow where you have zero flow with a 6.4M pump head?.

 

[rcpilot]

Can you just do up another line diagram just on that circuit including the rads, pump, 3 way valve & expansion vessel etc.
If the lines are clear then I would be almost 100% sure that a higher head pump will not sort the problem, we know (proved) that the Alpha 3 has a 6.4M head available and pumps 0.6m3/hr at this head, a 8M pump would increase the 0.6m3/hr flow to 0.67m3/hr and a 10M pump will increase the flow from 0.6m3/hr to 0.75m3/hr but neither can increase or get anything to flow where you have zero flow with a 6.4M pump head?.

Hi john the line drawing is in the attachment and my way of thinking if there was a restriction in the flow after the "Y" plan valve any radiator that was prior to that restriction would heat up normally, if there was any restriction in the return line any radiator that was prior to that restriction would heat up normally, as the towel rails are both heating up and the rest of the system is just warming up or not getting warm the restriction if it was in the flow is between the towel rails and the kitchen, if it was in the return again the restriction would be between the towel rails and the kitchen, what do you think?

 

[John.g]

That's great Ken, one picture is worth a thousand words.
From your post #80

All Rads ON 0.6m3/hr 34W
Large T.Rad Hot
Small T.rad Hot
Back B.room Hot
Front B.room L.warm
Entrance Cold
Sitting Room Cold
Kitchen Just Off Cold

Small T.rad Off, remaining Rads ON 0.4m3/hr 32W
Large T.Rad Hot
Small T.rad Off
Back B.room Hot
Front B.room L.warm
Entrance Cold
Sitting Room Cold
Kitchen Just Off Cold

Bothl T.rads Off, remaining Rads ON 0.0m3/hr 22W
Large T.Rad Off
Small T.rad Off
Back B.room warming up
Front B.room warming up
Entrance Cold
Sitting Room just about warming up
Kitchen Just about warming up

What strikes me straight away is the back bedroom, It stays Hot in the first two cases and is heating up with both T.rads off but with apparently no pump flow.
If its getting hot then that sort of proves that there is a flow through the main flow/return circuits? Can you try that Back B.room rad on only and see the pump values, if any?,

Are you sure that the isol valves on the 3 "cold" rads, Kitchen, Entrance and sitting room, are fully opened?

Flushing everywhere you can with the mains is about the most logical step now.

Your observations re restrictions make sense so running the back b.room on its own just might tell something.

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[rcpilot]

That's great Ken, one picture is worth a thousand words.
From your post #80

All Rads ON 0.6m3/hr 34W
Large T.Rad Hot
Small T.rad Hot
Back B.room Hot
Front B.room L.warm
Entrance Cold
Sitting Room Cold
Kitchen Just Off Cold

Small T.rad Off, remaining Rads ON 0.4m3/hr 32W
Large T.Rad Hot
Small T.rad Off
Back B.room Hot
Front B.room L.warm
Entrance Cold
Sitting Room Cold
Kitchen Just Off Cold

Bothl T.rads Off, remaining Rads ON 0.0m3/hr 22W
Large T.Rad Off
Small T.rad Off
Back B.room warming up
Front B.room warming up
Entrance Cold
Sitting Room just about warming up
Kitchen Just about warming up

What strikes me straight away is the back bedroom, It stays Hot in the first two cases and is heating up with both T.rads off but with apparently no pump flow.
If its getting hot then that sort of proves that there is a flow through the main flow/return circuits? Can you try that Back B.room rad on only and see the pump values, if any?,

Are you sure that the isol valves on the 3 "cold" rads, Kitchen, Entrance and sitting room, are fully opened?

Flushing everywhere you can with the mains is about the most logical step now.

You don't have permission to view attachments. Attachments are hidden.

Hi john put mains pressure to the flow after disconnection from the "Y" plan valve thus eliminating pump, boiler, "Y"plan valve and domestic hot tank, both towel rails shut off from flow, only kitchen rad fully open did get flow but as the piping to that rad is 8mm bore got a reduced flow but i would have thought that if mains pressure was going through it the water would have squirted out but it did not could stop it with light finger pressure, so I opened the back bedroom so only kitchen and back bedroom fully open flow increased but not to what I would have expected could stop it with finger pressure, which makes me think that there is a restriction somewhere in the system, to my thinking as before between towel rails and kitchen whether it's in the flow or return needs investigation, I am going to try and rod the flow and return with welding rods joined together, see what happens.

 

[John.g]

You certainly shouldn't be able to plug any opening with your finger doesn't matter how restricted the pipe is as the pressure will build up regardless? assuming mains pressure.

Maybe prove main piping clear first by breaking the return at the boiler and flushing through, then measure into a bucket for 30 secs or so to get the LPM, by making a educated guess at the mains pressure then can see if flowrate is ok for x meters of 15mm piping?.

 

[rcpilot]

You certainly shouldn't be able to plug any opening with your finger doesn't matter how restricted the pipe is as the pressure will build up regardless? assuming mains pressure.

Maybe prove main piping clear first by breaking the return at the boiler and flushing through, then measure into a bucket for 30 secs or so to get the LPM, by making a educated guess at the mains pressure then can see if flowrate is ok for x meters of 15mm piping?.

At this moment I think I have made some progress, as I said I was going to rod the pipework with 1/8 gas welding rods soldered together with a length of aprox 12-15 foot, I rodded the return which I had previously cut nothing going on there, I then cut the flow and the rod went in so far and I felt a bit of resistance so I pushed and fed the rod in further and used an in and out motion till it felt quite easy, then I connected the mains to the return opened up the furthest rad from the boiler connected a drain to the flow so that if there was anything in the system it would not flow round the system but out of the flow into the shower tray, you should have seen the amount of hard lumps of magnetite that came out, I am going to rod it again and see if any more comes out once it is clear I will reinstate the pipe work and try it, if all is clear or much improved I am thinking of getting it power flushed then fitting a magnaclean.

 

[rcpilot]

At this moment I think I have made some progress, as I said I was going to rod the pipework with 1/8 gas welding rods soldered together with a length of aprox 12-15 foot, I rodded the return which I had previously cut nothing going on there, I then cut the flow and the rod went in so far and I felt a bit of resistance so I pushed and fed the rod in further and used an in and out motion till it felt quite easy, then I connected the mains to the return opened up the furthest rad from the boiler connected a drain to the flow so that if there was anything in the system it would not flow round the system but out of the flow into the shower tray, you should have seen the amount of hard lumps of magnetite that came out, I am going to rod it again and see if any more comes out once it is clear I will reinstate the pipe work and try it, if all is clear or much improved I am thinking of getting it power flushed then fitting a magnaclean.

Hi John HURRAY sorted the rads are getting hot now just goes to show magnetite the root of all evils, rodded the flow for the second time and got a lot more out, I am going to get the system power flushed after we come back from our hols, then I am going to fit a magnaclean, obviously the heating will get better once I have balanced it, it still has the Alpha 2 pump in it, I will keep the Alpha 3 as a spare.
Thanks for all your help much appreciated
All the best Ken

 

[John.g]

Excellent news, I will have a few extra drops of Jamesons tonight not to mention a rake of Guinness.

Does the Alpha 2 display values as well?, W (watts) will do fine. If so, when you get a chance you might run it on CP2 which is 3M and post the values, or/and any values you have just now, that will give a very good indication of how clean the system is.

What exactly does a power wash achieve that you havn't already achieved, or how does it work??. you can flush out each rad individually in your own time and add inhibitor when all is done.