Opening upstairs rad reduces noise in downstairs rads !

[swebb99uk]

Hi, a bit of advice required.

I've been getting a lot of fast water flowing sounds from three radiators downstairs but not all and upstairs they are quiet, well most of the time. I've bled the system 3 times and also played around with the locks and balancing the system. I can make small improvements but not much. This system is running on a new Worcester Bosch CDI combi boiler.

Last night I noticed that if I opened two radiators upstairs in a room i usually don't heat the noise in the downstairs rads reduced by about 50%. If I closed the rads back off again using the TRV's the sounds came back. I played around opening these two rads in combination and one in particular makes the difference but I really need both open to make the big difference. Interestingly if I don't open the one which makes the big difference I can hear the gushing water sound in the other.

Why would opening a couple of rads upstairs (and only two in particular) cause the nouse in three rads downstairs to decrease ? I don't undersand how they can have that effect. Opening and closing any other rads upstairs has not effect at all. As far as I remember the pipes that came out of the boiler went in to the kitchen and then branched off two going along under floor to the lounge and feeding the downstairs rads and two staying at kitchen ceiling level going under the bathroom floor and feeing upstairs.

I should add I've been in the house 3yrs and the heating has always been fairly noisy and I recently had an extension fitted and a new CDI boiler fitted with a couple of extra rads downstairs. I had hoped this would have improved the noise but if anything it is worse.


Any idea's ?

Thanks

 

[SJB060685]

What are the size of pipes feeding downstairs rads? Water flowing noise is often due to water flow speed of over 1 to 1.5 m/s. Water moves faster through smaller pipework

 

[swebb99uk]

What are the size of pipes feeding downstairs rads? Water flowing noise is often due to water flow speed of over 1 to 1.5 m/s. Water moves faster through smaller pipework

Hi thanks for the response. Thats actually something I had checked and as far as I can see all pipework is the same large diameter as somebody in the past had updated all of the system, probably in the 90's I should think.

 

[steadyon]

Some cheap TRVs can make the most appalling noises occur in the radiator to which they are attached, or even to others. The noise often disappears by altering the TRV setting by a fraction, but will come back.
What TRVs do you have fitted?

 

[swebb99uk]

Some cheap TRVs can make the most appalling noises occur in the radiator to which they are attached, or even to others. The noise often disappears by altering the TRV setting by a fraction, but will come back.
What TRVs do you have fitted?

I seem to have a bit of a mix, some old and some new, the new ones are Eres ? Not sure about the old ones. I have played around with the trv settings and it doesn't seem to make much difference unless I stop the flow. I even removed the tops on a few to make sure nothing was sticking. The ones upstairs when I fully open to reduce the noise downstair obviously reduce the noise when fully open but the noise comes back when fully closed. It almost seems the wrong way around as to what you would expect to me !

 

[centralheatking]

Hi, a bit of advice required.

I've been getting a lot of fast water flowing sounds from three radiators downstairs but not all and upstairs they are quiet, well most of the time. I've bled the system 3 times and also played around with the locks and balancing the system. I can make small improvements but not much. This system is running on a new Worcester Bosch CDI combi boiler.

Last night I noticed that if I opened two radiators upstairs in a room i usually don't heat the noise in the downstairs rads reduced by about 50%. If I closed the rads back off again using the TRV's the sounds came back. I played around opening these two rads in combination and one in particular makes the difference but I really need both open to make the big difference. Interestingly if I don't open the one which makes the big difference I can hear the gushing water sound in the other.

Why would opening a couple of rads upstairs (and only two in particular) cause the nouse in three rads downstairs to decrease ? I don't undersand how they can have that effect. Opening and closing any other rads upstairs has not effect at all. As far as I remember the pipes that came out of the boiler went in to the kitchen and then branched off two going along under floor to the lounge and feeding the downstairs rads and two staying at kitchen ceiling level going under the bathroom floor and feeing upstairs.

I should add I've been in the house 3yrs and the heating has always been fairly noisy and I recently had an extension fitted and a new CDI boiler fitted with a couple of extra rads downstairs. I had hoped this would have improved the noise but if anything it is worse.


Any idea's ?

Thanks

Its often the case that the TRV valves are on the wrong side because they are not universal, some are
others not, its easy to check but if they are wrong way round they can 'bump back' and the vibration comes out where ever....mastermind now ....centralheatking

 

[swebb99uk]

Its often the case that the TRV valves are on the wrong side because they are not universal, some are
others not, its easy to check but if they are wrong way round they can 'bump back' and the vibration comes out where ever....mastermind now ..centralheatking

Great thanks, how do I check them ?

 

[centralheatking]

Great thanks, how do I check them ?

There might be an arrow indicating the direction of flow to return, hot side to cooler side so when heating starts up feel the pipes either side of the rad and determine which end heats up first. Or you could turn off the valve and see if the bumping ceases as a second method. centralheatking

 

[doitmyself]

Which version of the WB CDi boiler do you have?

How many radiators do you have?

 

[swebb99uk]

Which version of the WB CDi boiler do you have?

How many radiators do you have?

It's the 34 CDI classic ERP and I have 3 vertical rads, 2 towel rails and 6 normal rads, various sizes.

 

[swebb99uk]

There might be an arrow indicating the direction of flow to return, hot side to cooler side so when heating starts up feel the pipes either side of the rad and determine which end heats up first. Or you could turn off the valve and see if the bumping ceases as a second method. centralheatking

Well I had a play around with a few of the rads. What I have found are most have the TRV's set up so that hot water exits via them, however the small rad which is either the first or last rad in the loop upstairs has an arrow indicating the water should exit via it but actually enters via it. This is the rad that when closed causes increased water gushing noise (like fast water under pressure) in some of the downstairs rads. When open the noise reduces a fair but but is still more than you would expect.

I also noticed that my hallway radiator is letting the hot water in via the TRV and there is some writing on the value but it doesn't appear to have an arrow, the text appers to read Covmap or something like that with a strange almost M shapped symbol below it. This rad also suffers from the water gushing sound.

 

[centralheatking]

Well I had a play around with a few of the rads. What I have found are most have the TRV's set up so that hot water exits via them, however the small rad which is either the first or last rad in the loop upstairs has an arrow indicating the water should exit via it but actually enters via it. This is the rad that when closed causes increased water gushing noise (like fast water under pressure) in some of the downstairs rads. When open the noise reduces a fair but but is still more than you would expect.

I also noticed that my hallway radiator is letting the hot water in via the TRV and there is some writing on the value but it doesn't appear to have an arrow, the text appers to read Covmap or something like that with a strange almost M shapped symbol below it. This rad also suffers from the water gushing sound.

Take a piccy of the valves, looks like were getting somewhere, and it might be a diy thing. chking

 

[swebb99uk]

Take a piccy of the valves, looks like were getting somewhere, and it might be a diy thing. chking

Hi I've attached pics of the hallway trv value which has some writing on it and the water flows in to the rad via it which I'm not sure is correct. I've also attached a pic of the trv valve on the small rad which seems to be making the difference when open (downstairs rads fairly quiet) and closed (downstairs rads sound like high pressure water is going through them). That valve has no writing on it but appears to have writing of some marks the backside of it which I can feel with my fingers, the water is entering the rad via it. I've also attached a pic of the locking valve on the lounge rad that looks like it has seen better days.

I shoudl also add this morning I checked for air in the system again and found some in the highest rad (tall bathroom towel rail) and a bit in my bedroom rad. I was a little supprised as I only checked a couple of weeks ago (maybe 3 or 4!) and sorted it.

I also opened all trv's to 5 this morning to get the air out and after turned the heating up. Most of the rads I could hardly tell were on, no sound. The hall rad I could but it was much quieter than usual. However I noticed the front lounge rad and the hall rad even though they were getting hot at the top they were a fair bit cooler near the bottom and also on the exit pipes there was a big drop off in temperature and the lounge one especially was still basically cold after 10 mins so I gave the lock values on both half a turn and this has improved it somewhat.

I finally went up stairs and turned the trv on the small rad which appeared to be causing the issues down to zero again, went back down stairs and yep all the noise is back. Basically the hallway and lounge rads sound like water is going through at a high rate. The new tall rads in the rear lounge and kitchen also sound the same but less so.

So I am thinking maybe the offending rad had the trv on the wrong end. Maybe the hallway and lounge valves need changing and I'm also wondering if there might be sludge in the hallway and front lounge rads as they are fairly old. That might also be the case with the offending rad upstairs.

By the way is that Vaughan Williams in the pic ?

 

[centralheatking]

Hi I've attached pics of the hallway trv value which has some writing on it and the water flows in to the rad via it which I'm not sure is correct. I've also attached a pic of the trv valve on the small rad which seems to be making the difference when open (downstairs rads fairly quiet) and closed (downstairs rads sound like high pressure water is going through them). That valve has no writing on it but appears to have writing of some marks the backside of it which I can feel with my fingers, the water is entering the rad via it. I've also attached a pic of the locking valve on the lounge rad that looks like it has seen better days.

I shoudl also add this morning I checked for air in the system again and found some in the highest rad (tall bathroom towel rail) and a bit in my bedroom rad. I was a little supprised as I only checked a couple of weeks ago (maybe 3 or 4!) and sorted it.

I also opened all trv's to 5 this morning to get the air out and after turned the heating up. Most of the rads I could hardly tell were on, no sound. The hall rad I could but it was much quieter than usual. However I noticed the front lounge rad and the hall rad even though they were getting hot at the top they were a fair bit cooler near the bottom and also on the exit pipes there was a big drop off in temperature and the lounge one especially was still basically cold after 10 mins so I gave the lock values on both half a turn and this has improved it somewhat.

I finally went up stairs and turned the trv on the small rad which appeared to be causing the issues down to zero again, went back down stairs and yep all the noise is back. Basically the hallway and lounge rads sound like water is going through at a high rate. The new tall rads in the rear lounge and kitchen also sound the same but less so.

So I am thinking maybe the offending rad had the trv on the wrong end. Maybe the hallway and lounge valves need changing and I'm also wondering if there might be sludge in the hallway and front lounge rads as they are fairly old. That might also be the case with the offending rad upstairs.

By the way is that Vaughan Williams in the pic ?

Yes it is Vaughan Williams in my pic, great composer, well spotted. I think that if you can bear it wait till the weather warms up...then If it was myself I would switch of drain down, flush the system thro..we will talk you thro that and yes the rads do look very old so replace. In the meantime mark all your rads with red tape on the pipe side that gets hottest first and blue for the other. New rads and trv are cheap as chips when the cold season ends. A decent set of rads with nice new valves does wonders for house values. centralheatking

 

[swebb99uk]

Yes it is Vaughan Williams in my pic, great composer, well spotted. I think that if you can bear it wait till the weather warms up...then If it was myself I would switch of drain down, flush the system thro..we will talk you thro that and yes the rads do look very old so replace. In the meantime mark all your rads with red tape on the pipe side that gets hottest first and blue for the other. New rads and trv are cheap as chips when the cold season ends. A decent set of rads with nice new valves does wonders for house values. centralheatking

Great idea CP Yes I was thinking of changing the rads next year so spot on with that. The only one that might be an issue is the front lounge one which is in a bay and is basically three bits of flat rad welded together at a specific angle for the bay with the right lengths also. However it might be a good idea for me to get a new one as I am doing that room up as we speak with a view to getting new carpet in in the spring.

Cheers.

 

[Ted808]

I would put in a bypass if you don't have one, the bypass in combi boilers are often not quite adequite for more rad's or the pipe layout offers too much resistance, or something I don't know!
I did have major issues with noise in a system and after many head scratching hours and seeking solutions and advice, someone suggested a bypass and it solved the noise problem...

 

[centralheatking]

I would put in a bypass if you don't have one, the bypass in combi boilers are often not quite adequite for more rad's or the pipe layout offers too much resistance, or something I don't know!
I did have major issues with noise in a system and after many head scratching hours and seeking solutions and advice, someone suggested a bypass and it solved the noise problem...

Ted he could should and might have a rad with a lockshield/wheelhead valve at each end no TrV which will act as a bypass, usually in the bathroom ..centralheatking

 

[swebb99uk]

Ted he could should and might have a rad with a lockshield/wheelhead valve at each end no TrV which will act as a bypass, usually in the bathroom ..centralheatking

Mmmm I must admit I've not heard about the bypass valve before but I do have a tall towel radiator in the bathroom which I think is the first rad in the upstairs system. That has two chrome nobs at the bottom that both turn and I was at a bit of a loss at to why there was no trv on one side !

 

[centralheatking]

Mmmm I must admit I've not heard about the bypass valve before but I do have a tall towel radiator in the bathroom which I think is the first rad in the upstairs system. That has two chrome nobs at the bottom that both turn and I was at a bit of a loss at to why there was no trv on one side !

The bypass rad works if the valves are open usually with lockshield caps centralheatking

 

[swebb99uk]

Well finally had a chance to play around with the boiler settings a little bit today. What I found from looking at a guide for it on the WB site was that the pump has several modes of operation. Proportional pressure and constant pressure.

The default setting is Proportional pressure high and there is a information note in the document stating that "In order to save as much energy as possible and to minimise the possibility of water circulation noise, a low characteristic should be chosen. "

So I changed the mode to Proportional pressure low and the system rads were almost silent however the I think the boiler wasn't pumping the water away quick enough because the temp would raise fairly quick and when reached it would cut out the flame early and after a minute or two re-ignite but by that time the temp had settled back down to 30c or so from it's max setting of 64c ( i set that). Obviously eventually the system would be fully up to heat but that would take an age. So I changed the setting to constant pressure medium and tried that. This time ignition stayed on until all the rads felt hot and then ignition was turned off and the pump continued until a few minutes later it was re-ignited. The rads were almost silent. So I have kept those setting and I will see how I get on.

I have also noticed that the curved rad in the lounge bay window heats up most of the way round fairly quickly byt the outlet pipe never seems to get very warm even though the rad is which is strange. That pipe has an old TRV on it so I removed the top to check the pin moves and it does but not much. I'm not convinced it is working correctly and a but suspicious that it might be direction sensitive. There is some writing on the wall side but i can't read it. I think I might get a new TRV and locksheild valve for it and replace when the weather is a bit better.

I might have a bit more of a play with the boiler settings but I think the high setting was the main cause of the noise and probably the cause of the noise when the old CDI boiler was fitted but not quite so bad.
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I'm at a total loss now, I changed the pump map last night as mentioned in my last message and the rads were almost silent and thought I had cracked the issue but I woke this morning when the heating came on to the same sound as previously like loud rushing water flowing through most of the radiators. I've previously bled the system twice, messed around with balance, and now even turned down the pump but the sound is back

I can't think why last night it would be almost silent but today it would be noisy again. It's driving me mad.
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Yet another quick update. The heating switched off for 15 mins because it reached temprature and then I hardly noticed it when it came back on as it is no quiet again

How can one cycle it sound like high pressure water shooting through the system and the next be almost silent. The pump is now set on a constant medum speed so its not like it is going through different speeds I wouldn't have thought.

Totally confused.
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Actually I now wonder if I'm write about the speed being fixed, as I have set the map to constant pressure middle (number two on graph) and H is residual heat and the V volume of water then it looks like if the system starts from cold (morning) then the volumne is a fair bit higher so i guess the pump is a fair bit higher (its sounds like that near the boiler). In which case this would explain the sound of rushing water in the rads. The one things I don't get then is that after 20 mins or so I would have expected the sound to go down as all the rads have got hot. It would appear if you adjust the thermostate (nest) so the boiler stops, leave it a few minutes then adjust the thermostate again so that it comes on again the system is fairly quiet. So why doesn't it do this when first coming on in the morning or the evening and hence start with a high volume and then adjust as the whole system heats !!!

I suppose I could try setting the nest with a couple of cycles in the morning, one heat the house up for say 20mins then switch off for 10 mins then back on with a higher normal thermostate reading.

Still puzzled though.

 

[doitmyself]

In which document did you find the instructions about changing the pump settings? It's not in the Installation and Service manual for the CDi Classic erp.

 

[John.g]

Hi I've attached pics of the hallway trv value which has some writing on it and the water flows in to the rad via it which I'm not sure is correct. I've also attached a pic of the trv valve on the small rad which seems to be making the difference when open (downstairs rads fairly quiet) and closed (downstairs rads sound like high pressure water is going through them). That valve has no writing on it but appears to have writing of some marks the backside of it which I can feel with my fingers, the water is entering the rad via it. I've also attached a pic of the locking valve on the lounge rad that looks like it has seen better days.

I shoudl also add this morning I checked for air in the system again and found some in the highest rad (tall bathroom towel rail) and a bit in my bedroom rad. I was a little supprised as I only checked a couple of weeks ago (maybe 3 or 4!) and sorted it.

I also opened all trv's to 5 this morning to get the air out and after turned the heating up. Most of the rads I could hardly tell were on, no sound. The hall rad I could but it was much quieter than usual. However I noticed the front lounge rad and the hall rad even though they were getting hot at the top they were a fair bit cooler near the bottom and also on the exit pipes there was a big drop off in temperature and the lounge one especially was still basically cold after 10 mins so I gave the lock values on both half a turn and this has improved it somewhat.

I finally went up stairs and turned the trv on the small rad which appeared to be causing the issues down to zero again, went back down stairs and yep all the noise is back. Basically the hallway and lounge rads sound like water is going through at a high rate. The new tall rads in the rear lounge and kitchen also sound the same but less so.

So I am thinking maybe the offending rad had the trv on the wrong end. Maybe the hallway and lounge valves need changing and I'm also wondering if there might be sludge in the hallway and front lounge rads as they are fairly old. That might also be the case with the offending rad upstairs.

By the way is that Vaughan Williams in the pic ?

I have 8 rads with TRV's, (and 2 without) all mounted horizontally on the returns as I reckon it gives far more representative room temperature sensing due to the lower rad radiated temperature if mounted vertically (the more "normal" way) on the flow side, also a uni directional TRV, if mounted horizontally on the return, will still be correct, ie , the flow from underneath the valve seat, I can run my 6M pump at its highest (normally set to 4M PP mode, OFCH) fixed speed setting and still get no noise from the TRVs etc, I will hear a bit of a "pebbly" sound from the pump possibly due to it nearing cavitation at this excessive setting. I have seen uni directional TRVs mounted the wrong way round without any noise issues (can't comment on the control accuracy) so just wonder if your problem has much to do with the TRVs, sounds more like a entrained air problem to me. Can you temporarily change the flow temperature to say 60C to see if the noise dies down, some systems seem to have incurable noise problems if the flow temp is > 70C.
Should also perhaps mention that I have all l/shield valves fully open as I have no detectible balancing problems.

 

[swebb99uk]

In which document did you find the instructions about changing the pump settings? It's not in the Installation and Service manual for the CDi Classic erp.

I found the info the service engineers documentation online

here
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I have 8 rads with TRV's, (and 2 without) all mounted horizontally on the returns as I reckon it gives far more representative room temperature sensing due to the lower rad radiated temperature if mounted vertically (the more "normal" way) on the flow side, also a uni directional TRV, if mounted horizontally on the return, will still be correct, ie , the flow from underneath the valve seat, I can run my 6M pump at its highest (normally set to 4M PP mode, OFCH) fixed speed setting and still get no noise from the TRVs etc, I will hear a bit of a "pebbly" sound from the pump possibly due to it nearing cavitation at this excessive setting. I have seen uni directional TRVs mounted the wrong way round without any noise issues (can't comment on the control accuracy) so just wonder if your problem has much to do with the TRVs, sounds more like a entrained air problem to me. Can you temporarily change the flow temperature to say 60C to see if the noise dies down, some systems seem to have incurable noise problems if the flow temp is > 70C.
Should also perhaps mention that I have all l/shield valves fully open as I have no detectible balancing problems.

Hi thanks for the response. My heating is actually set to 61 normally. I am beginning to think the mixture of all the TRV's of different ages isn't the best of situations, so maybe I would be better getting all the old ones and lockshields replaced.

 

[doitmyself]

I found the info the service engineers documentation online

Thanks. It didn't come up in any searches I did on the WB website

 

[swebb99uk]

Thanks. It didn't come up in any searches I did on the WB website

Yeah no problem, I had to search for it, it doesn't come up on their website for some reason !

 

[ShaunCorbs]

trv noise i would say prob doesnt happen as the trv is shut eg room upto temp so close one trv at a time a day and see if the noise happens in the next morning again

 

[swebb99uk]

trv noise i would say prob doesnt happen as the trv is shut eg room upto temp so close one trv at a time a day and see if the noise happens in the next morning again

Good idea thanks for that, I'll give it a try.

 

[doitmyself]

How can one cycle it sound like high pressure water shooting through the system and the next be almost silent. The pump is now set on a constant medum speed so its not like it is going through different speeds I wouldn't have thought.

Actually I now wonder if I'm write about the speed being fixed, as I have set the map to constant pressure middle (number two on graph) and H is residual heat and the V volume of water then it looks like if the system starts from cold (morning) then the volumne is a fair bit higher so i guess the pump is a fair bit higher (its sounds like that near the boiler). In which case this would explain the sound of rushing water in the rads.

Constant speed and constant pressure are not the same thing. If a pump is running at constant speed the graph of pressure against flow will be like the traditional pump graph e.g speeds 1, 2 and 3 of a UPS Selectric 15/50

Constant pressure is achieved by varying the speed as the flow varies.

By the way, H is the head, i.e pressure, not heat; and V is the flow, litres per sec.

As for your noise problem, it sounds as if the water is travelling too fast through the pipes. This suggests that the system has not been properly balanced. This is not surprising if it has been done with the pump set to a proportional pressure setting. One of the fixed speeds has to be used.

An automatic bypass has been suggested. If it is installed the pump will have to be on a fixed speed. If a proportional pressure setting is used the ABV will not work correctly; and if a constant pressure setting is used the ABV will be either always open or always closed.

 

[swebb99uk]

Constant speed and constant pressure are not the same thing. If a pump is running at constant speed the graph of pressure against flow will be like the traditional pump graph e.g speeds 1, 2 and 3 of a UPS Selectric 15/50
View attachment 42227

Constant pressure is achieved by varying the speed as the flow varies.

By the way, H is the head, i.e pressure, not heat; and V is the flow, litres per sec.

As for your noise problem, it sounds as if the water is travelling too fast through the pipes. This suggests that the system has not been properly balanced. This is not surprising if it has been done with the pump set to a proportional pressure setting. One of the fixed speeds has to be used.

An automatic bypass has been suggested. If it is installed the pump will have to be on a fixed speed. If a proportional pressure setting is used the ABV will not work correctly; and if a constant pressure setting is used the ABV will be either always open or always closed.

Great thanks for reply, some really useful stuff. Yes I balanced it whilst in proportional high pressure mode so that's highlighted a problem and my large bathroom towel rail has two none trv vales so I believe it's acting as a bypass.

Sounds like I should set in fixed speed mode 4 or 5, balance and then move back to proportional and see what happens!

Thanks

 

[swebb99uk]

Hi all just thought I'd update on this.

I've now had three old rads replaced and most of the trv's and lock sheilds on the other rads. I'v also had one extra rad added and in all my verticle rads I've had diverter values installed (none were from the factory WTF!).

It's now heating the house up quicker and the noise is almost to a level where I can hardly hear anything is on. One interesting thing is the plumber basically said have all the lock valves fully open on these new EU spec'd WB boilers unless there is an issue of heating one or more rads. So thats what I now have. I also have no TRV on the hallway radiator and I will shortly be moving my nest controller in to the hallway and using the TRV's in the longe to control the heating in that room rather than the controller.

Thanks for the advice.