oil boiler cycling

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frpcraig

Hi All,great forum ,hope you can help?
I have an old camray compact 50/70 oil boiler, with a rdl g2-sx burner.
It has been serviced every 2 years by the same guy.
The time for the service seemed to be short so I did some investigating myself.
I removed the burner and hacked off 1/4 inch of carbon build up in the chamber.
He hoovered it each time?
The end result is now the rads/hot water now heat up much more quickly and reach a decent temp.
The down side is the boiler now short cycles.££££££!
The boiler runs 11 rads and a hot water tank.
If I put on only the hot water there is no short cycling.
I have replaced a defective roomstat and a defective 2 way motorised valve.
The system appears basic to say the least.
There is only one motorised valve to switch off the ch and a tap to isolate the hw tank (with no tank stat)
The boiler will run for a while until it reaches temp then cycle 3 mins on 3 mins off when asked for ch and hw.
The oil pump runs standard as far as I know and the nozzle is 0.65 60 W.
Do you think running the max size nozzle is causing the short cycling and I should drop down to a 0.40 nozzle to keep the burner on for longer.
With the same set up it seemed to run ok before I cleaned the chamber properly, is the boiler oversize??
Many thanks,
 
oil boilers require servicing annually to work efficiently for a start. all the cdarbon was probably masking a stat that is now able to operate and is probably locking out to cause short cycling or you fiddling has cocked up the controls side, basically you need to get it serviced ,set up and checked. to be efficient you need a hw cyl stat and another motorised valve on the system, then you might save some money
 
Hi thanks for the quick reply!
As I mentioned the boiler servicing was not up to scratch.
The boiler stat and the high limit stat are in pockets above the tank and have no carbon issues.
There is no 'locking out' of stats.
The stats operate correctly.
'fiddling has cocked up the control side'
Can you elaborate??
Many thanks
 
might well be one of the boiler stats is now getting some heat now all the carbon gone and its failing and causing the short cycling
 
Thanks lame plumber,
As I have said, the stat probes are above the heat chamber so they never had any carbon build up.
They all work to spec.
There is one high limit stat working correctly and the boiler stat also working correctly.
The boiler is heating the tank much more efficiently now I have scrapped all carbon off the inside.
No other changes.
All as before this.
Any more ideas???
 
no but the burner chamber was! stopping heat reaching them, get someone in who can a service it, b set it up and then c fault find it
 
Take a look at the OFTEC website, there is a section where you put in your post code and get a list of competent technicians for your area.

Carbon build up is not a good sign, depends on what you are burning diesel or kerosene (not familiar with that brand) if you change the nozzle you will need the oil pressure re-set a smoke pump and a flue gas analyser to be sure the boiler is working properly.
 
Thanks peteheat, I will definitely be getting a full system analysis done.
The carbon build up is a result of many years of improper servicing, no wire brushing, no scraping etc.
I have done this job myself and it transformed the boiler from producing lukewarm water to hot water.
The burner oil pressure is set to 8 bar and can run nozzles between 0.4 up to 0.85 without the pressure needing to be changed.
My thoughts were as the boiler is now heating properly the 0.65 nozzle fitted is too large for my needs causing short cycling and too much heat loss through the exit, hence my thoughts on fitting a smaller nozzle.
What do you think?
Thanks
Craig
 
Hi,

My thoughts are the first thing needed is to find out why there was a carbon build up, which is why I was asking which fuel is being used, a properly set up burner will not build up carbon deposits to any great extent.

Many people are surprised at how little it takes to kill off the efficiency of the boiler so your cleaning is allowing the boiler to do what it was designed to, exchange heat, so well done.

On older boilers the manufacturers instructions are nothing more than a guide, a starting place for the engineer to get the correct mix of fuel and air, equally if not more important is the type of nozzle fitted, a heavy carbon build up is often caused by the flame actually touching the steel inside the boiler, the caveat was "subject to local conditions".

You are correct in that the boiler may now be generating too much heat, equally it could be caused by an old pump not being able to dissipate the heat fast enough, another cause of cycling can be retrofitting heating controls.

If you fit a .4 nozzle without the necessary equipment to set up the burner you could end up with a boiler that is not capable of meeting the heat demand of the house a drop of .25 is a lot, maybe the boiler was sized for the house when it had single glazing, practically no insulation etc we can only assume the boiler did suit the house when it was installed

I suggest starting with the heat demand for the house by calculating the heat loss, that is what determines the size of the boiler and the nozzle needed, if the heat loss of the house has changed over the years you may find the figures justify upgrading the boiler to a new smaller efficient condensing boiler, oil is too expensive to be getting the figures wrong.
 
Great reply, thanks.It sounds like you know my house!!
All of the things you mention make sense.
We bought the house 10yrs ago.
It's a 300 year old farmhouse ,not flashy more of a do-er upper!
We have replaced most of the single pane windows with double glazing and insulated the loft also.
I put a new danfoss pump in last year (the red one) and that appears to be still ok.
I would love to put a new more efficient boiler in and it is on my 'to do list' but I haven't got a pot to p**s in at the minute.
When I fire up the boiler from cold I can get all the rads up to temp in 20 mins and then the cycling starts. Before I cleaned the chamber the rads never really got up to temperature.
When it cycles I reckon it is doubling the fuel usage (kerosene) so I run for 20 mins then switch it off till the rads cool down.
All the different size nozzles applicable to my burner seem to have the same spray angle so hopefully the flame isn't hitting the sides of the chamber.
When we moved in kerosene was 13p a litre so you could leave it on for fun!
At 60p it becomes serious!
I will have a look for heat loss calcs and try and work it out.
My small nozzle arrives tomorrow so i'll try it and let you know the results Pete.
Thanks again
Craig
 
You say the stats are working fine, so surely if you turn the boiler stat (dial on the front - if it has one) it wont cycle, or at least will do less.
Please also tell us if all the rads get hot, upstairs and downstairs?
If you just stick a small nozzle in, youll be halving the output and ought to adjust the pump pressure to suit the combustion.
 
Last edited by a moderator:
frpcraig said:
Great reply, thanks.It sounds like you know my house!!
All of the things you mention make sense.
We bought the house 10yrs ago.
It's a 300 year old farmhouse ,not flashy more of a do-er upper!
We have replaced most of the single pane windows with double glazing and insulated the loft also.
I put a new danfoss pump in last year (the red one) and that appears to be still ok.
I would love to put a new more efficient boiler in and it is on my 'to do list' but I haven't got a pot to p**s in at the minute.
When I fire up the boiler from cold I can get all the rads up to temp in 20 mins and then the cycling starts. Before I cleaned the chamber the rads never really got up to temperature.
When it cycles I reckon it is doubling the fuel usage (kerosene) so I run for 20 mins then switch it off till the rads cool down.
All the different size nozzles applicable to my burner seem to have the same spray angle so hopefully the flame isn't hitting the sides of the chamber.
When we moved in kerosene was 13p a litre so you could leave it on for fun!
At 60p it becomes serious!
I will have a look for heat loss calcs and try and work it out.
My small nozzle arrives tomorrow so i'll try it and let you know the results Pete.
Thanks again
Craig
Click to expand...
fm what youve just said it seems you dont use an engineer to set up your boiler and thats probably half the problem. diy and boilers is stupid and dangerous and itll will have to take someone like yourself killing their family to force the government to make similar regulations to that of gas before fiddlers are made illegal, for good reason
 
Hi Craig,

The drop in nozzle size is substantial, I expect you will still have a boiler wasting fuel as it will be trying very hard to get up to temperature, the opposite of your original problem (cycling) you will also be sending a lot of unburnt fuel into the atmosphere.

At 60p a litre you don't have to save a lot of fuel to justify the cost of employing a professional who has the right equipment to get you the best out of every drop of fuel.

Personally when money is tight I hate the thoughts of my limited resources being wasted.

I have to agree with lame plumber legislation is needed to ensure that consumers treat oil systems with the respect they deserve because at worst they can kill, they can also cause major damage to the environment when not properly maintained.
 
Where is the boiler sited? If the pipes from it were underground, then severe heat loss can be a problem. If not then your boiler stat could be faulty.
Changing the nozzle to a very small one is nonsense. That output of boiler usually needs approx .6 nozzle. 11 rads (even smallish) & a hot cylinder will need that size of boiler output so do not lower it - have the nozzle replaced with proper size only. You haven't a clue tbh, needs an engineer to set it all up.
 
Thanks for the replies.
Bunker the rads both upstairs and downstairs all heat up to temp in 20 mins,
If I turn the boiler stat down it comes up to temp quicker then short cycles, if I turn up the boiler stat it takes a bit longer to get to temp then short cycles.
If I go from a 0.65 to a 0.4 I will reduce my gph by 37% rather than halving it as you mentioned.
Riellos spec sheet for my burner says you can run between a 0.4 and a 0.65 nozzle with the same pump pressure.

Lame plumber, if you re-read my posts I have always used a registered engineer, hence my issues!.

Peteheat, thanks again for your comments.
As mentioned I will get a stack temp ,co2 etc analysis done for sure.
What I object to is paying hundreds of pounds a year for an engineer not to service my boiler properly.
I am quite capable off scraping crap off the inside of my boiler if the engineer doesn't
I have found nozzle containers that vary from 0.4 to 0.65 in the case of my boiler.
I think my'engineer' has put bigger nozzles in over the years to combat the inefficient coked up chamber.
Best, thanks for your reply,
The boiler is sited in the downstairs toilet with a rad in it.No underground pipes
Most of the rads are singles and little.
I have no need to run the hw tank and the rads at the same time.
Cheers
Craig
 
If I go from a 0.65 to a 0.4 I will reduce my gph by 37% rather than halving it as you mentioned.
Click to expand...
Not talking about gph, talking about output Kws - the output on a .65 compared to a .4 is almost exactly halved at the same pressure, still you obviously know best....Im out.
 
Hundreds of pounds a year on servicing? Think I need to come down and work in your area.

It's surprising just bhow quick an oil boiler will fill with crap when something goes wrong.

Spec sheets will tell you nothing but data from bench mounted burners running in ideal 'factory' settings. In reality you are going to have issues swapping bits without the correct gear.

What we need is more people like yourself tinkering with oil boilers to ensure there are more fatalities. That way stricter legislation will brought in to bring oil into line with gas.

Stupid people will make it safer for all.
 
frpcraig said:
Lame plumber, if you re-read my posts I have always used a registered engineer, hence my issues!.


As mentioned I will get a stack temp ,co2 etc analysis done for sure.
What I object to is paying hundreds of pounds a year for an engineer not to service my boiler properly.
I am quite capable off scraping crap off the inside of my boiler if the engineer doesn't
I have found nozzle containers that vary from 0.4 to 0.65 in the case of my boiler.
I think my'engineer' has put bigger nozzles in over the years to combat the inefficient coked up chamber.

Having a boiler serviced every 2 years isnt enough to keep it running efficiently. if your paying hundereds of pounds a year for servicing and having to decoke your boiler, then prehaps you ought to reconsider if he knows what hes doing, you obviously dont if your assuming he's changing nozzle size to combat soot build up. more likely it's all he had in his nozzle selection at the time! you really should find a decent registered techie to do a decent job and for your information an hour and a half is quite normal for anaverage service, more for something like your boiler.
Click to expand...
 
Thanks again,
Look please stop shouting at me and telling me I am an idiot.
You don't know my background.
I do understand the dangers involved ,I am just fed up of paying for poor service.
I heat the house with coal fires and have electric showers etc so I am not at the mercy of the boiler.
I don't run the boiler other than tests when the house is empty.
Tonight i fitted the 0.4 nozzle and the burner runs continuously for 1 hour 20 mins, you may think that is insane but I know that the boiler does not short cycle running a smaller nozzle and runs on a 4 minute cycle on the 0.65 nozzle.
In fact the boiler has now shut off after reaching roomstat temp (this minute).
That took 1 hour and 20 mins.
Berfor with the 0.65 nozzle it would heat up to temp in 20 mins and short cycle.
I am timing now on the 0.4 nozzle to see when it starts up again.
Pete you mentioned the longer run time issue running a 0.4 nozzle,do you think a 1 hour 20 min run time from cold is ok.
Cheers
Craig
 
Ok then , last question,
What would everyone consider to be an acceptable/efficient cycle time?
Thanks
 
if its heating up quickly on a larger nozzle and then short cycling something is wrong with the thermostats somewhere, just because a very small nozzle takes longer for it to heat the whole system and then turn off doesnt mean its right. It only takes 10 mins to warm my rads and the boiler doesnt short cycle thereafter, you have a problem thats resolvable but needs looking at properly, advice now given why not take it for all our sakes.
 
Thanks lameplumber ,yes I have a new engineer booked in for next week.
What do you think an efficient cycling time is?
Thanks
 
if you mean how long to warm rads 10 mins reasonable and then your boiler should cycle on and off as required, and it will take however long it takes to cycle on and off, but obviosly not on off on off every minute or so.
 
I just want a rough idea lameplumber.
!0 mins off 10 mins on , 20 mins /30 mins etc.
A ballpark would be good,
I have read an oil burner comes to max eff, after 18 mins??
Thanks,
 
it will take at least 10 mins to reach peak efficiency as a boiler with correct flue temps etc, but then of course it will cycle on and off as req by need to heat return temp of water. best advice to you is to stop reading and trying to comprehend oil and burner manuals and just refer to the owners operating guide.
 
Last edited by a moderator:
Thanks for the replies.
Bunker the rads both upstairs and downstairs all heat up to temp in 20 mins,

About right.

If I turn the boiler stat down it comes up to temp quicker then short cycles, if I turn up the boiler stat it takes a bit longer to get to temp then short cycles.

Reads exactly the opposite to what I would expect, what controls your boiler firing?

If I go from a 0.65 to a 0.4 I will reduce my gph by 37% rather than halving it as you mentioned.
Riellos spec sheet for my burner says you can run between a 0.4 and a 0.65 nozzle with the same pump pressure.

Riello manufactured the burner not the boiler, it is the boiler manufacturer who spends the big money on R & D to ensure the correct burner, nozzle and settings are used to achieve the most efficient performance.

Lame plumber, if you re-read my posts I have always used a registered engineer, hence my issues!.

Peteheat, thanks again for your comments.
As mentioned I will get a stack temp ,co2 etc analysis done for sure.
What I object to is paying hundreds of pounds a year for an engineer not to service my boiler properly.

Far as I know from earlier posts I'm probably one of the most expensive service engineers who posts here, allowing for currency exchange rates I would be charging circa £100.00 for an oil boiler service.

I want my customers back again next year so if there is a problem with a job I do I want to know about it, I understand most who post here have a similar policy.

With respect I suggest you use a new service engineer / technician preferably one with a plumbing back ground.


I am quite capable off scraping crap off the inside of my boiler if the engineer doesn't
I have found nozzle containers that vary from 0.4 to 0.65 in the case of my boiler.

The burner can use nozzles in that range, that does not mean they suit the boiler in fact .65 is only part of the nozzle data.

I think my'engineer' has put bigger nozzles in over the years to combat the inefficient coked up chamber.
Best, thanks for your reply,
The boiler is sited in the downstairs toilet with a rad in it.No underground pipes
Most of the rads are singles and little.
I have no need to run the hw tank and the rads at the same time.
Cheers
Craig

You mention in a later post that it is now taking a continuous 80 minutes to achieve the same temperature the larger nozzle achieved in 20 minutes, the basic maths should be telling you all the advice you received was correct, you are using more oil with the smaller nozzle.

To answer your last question, the cycle time should be directly related to the heat loss of the building.

Nobody is calling you stupid we are trying to help by posting a few lines (I touch type with one finger) after we have completed a fairly hard days work, it is not always possible to trouble shoot a boiler problem without being in front of it.

Sorry I can't be of more help.
 
Thanks everyone, I have put the original nozzle back in the burner and promise to stop fiddling!
dontknowitall, I have found another manual red valve in the bathroom. It was wide open.
When I close it the boiler gets very hot then shuts down. There doesn't appear to be any short cycling when the valve is shut.
The boiler water temp stays hot for ages.
If I open the valve the boiler water temp (in the boiler tank) loses heat at the rate of 15 degrees celsius in 3 mins!
Is this the bypass valve you talked of?
Thanks
Craig
 
Is this a red headed valve (probably a gate valve?) at a copper cylinder?
If so, then could be there to balance the flow through the heating coil.
 
Thanks Best, it is a red headed valve ,it is in the hw tank area.
One connection to it goes up into the loft, one connection seems to connect to the top of the hw cylinder and the ( a smaller pipe) goes to the hot water tap in the bathroom sink???
I may be wrong but that's what it looks like.
I've done some more tests and with the valve open the boiler gets up to temp then cycles often at about 70 degrees according to the boilerstat.
When I fully close it the boiler tank temp hits 95 degrees but does not short cycle.
Any ideas??
Cheers
Craig
If I turn the valve shut the boiler tank temp gets up to 90 degrees
 
When I say the tank temp hits 90 degrees I mean the top , the bottom is 70 degrees if that helps??
 
No the boiler water tank.
I have the hot water cylinder shut off.
Cheers Simon.
 
frpcraig said:
Thanks Best, it is a red headed valve ,it is in the hw tank area.
One connection to it goes up into the loft, one connection seems to connect to the top of the hw cylinder and the ( a smaller pipe) goes to the hot water tap in the bathroom sink???
I may be wrong but that's what it looks like.
I've done some more tests and with the valve open the boiler gets up to temp then cycles often at about 70 degrees according to the boilerstat.
When I fully close it the boiler tank temp hits 95 degrees but does not short cycle.
Any ideas??
Cheers
Craig
If I turn the valve shut the boiler tank temp gets up to 90 degrees
Click to expand...

My reading of the above may appear crazy (not aimed at you Craig) is it possible that the hot water supply to the sink is being taken from the heating circuit?

Without a few photos or preferably standing in front of the installation I can't figure out if the gate valve is meant to be restricting the expansion from the heating or the cylinder (both no no's).

Craig would you mind uploading a few photos?
 
Hiya Pete,
There is another red tap (call that one no. 1) on another pipe near the hw tank near the red tap we are on about (call this one no.2).
If I turn no.1 tap on then the hw tank heats up on the ch and hw setting on the programmer as well as the rads .
If I put the ch and hw setting on the programmer and close the red tap (no. 1)then the heating is on but the tank does not heat.
This tap is on a pipe which connects directly to the top of the hot water cylinder and then goes to multiple junctions ?
If I put the programmer to hw only the the rads don't heat but the boiler gets to temp before the hwc is at temp.
Please tell me what area of pics you need and I'll put them up (with instructions)
Thanks again
Craig
 
If it helps pete..................
We only ever had hot water from the taps when the I turn on the no.1 tap (from the cylinder).
When I crack open the no.2 valve a bit we get warm water out of the bathroom tap (not hot)
 
best advice is just get a decent engineer in to look at your system, no one has any idea what valve does what unless you can see or trace them back so
giving advice like this is pointless.
 
Much better the two valves are serving different purposes, I have to agree with lame plumber the best advice will be from the person standing in front of the system, turning on and off valves will never prove to be a safe efficient way to control your heating system.

Heating controls play a big a part in the efficiency and comfort levels that can be achieved from any boiler, a big advantage is anything you do now can be part of a full upgrade of your heating system so no money is wasted.

There are good engineers out there you were unlucky with the last one doesn't mean we are all the same, best to ensure the next one is a heating contractor who does more than just service boilers, sadly the trade is being broken up into different segments specialising in parts of the overall trade.
 
Failing that you can always let the tyres down, that will stop the boiler cycling.

Just a bit of levity, pictures or professional me thinks.
 
I've cracked the mystery tap open a fraction and the boiler comes up to temp and doesn't keep cycling on and off. The boiler retains it's heat rather than plummeting as it did when the valve was wide open.
Must be a crude way to control the return temp.
Anyway as suggested I'll leave it alone till someone who knows what there doing has a look.
While i'm here............
I am trying to balance the rads (safe for me to attempt???)
I have followed instructions and have managed to get somewhere near a ten degree drop.
To get this drop on some of the rads the lockshield is barely cracked open , does that sound normal??
Ta,
 
Hi Craig,

The purpose behind balancing the radiators is to ensure an even distribution of the heat around the system, it is not unusual for the rads nearest the boiler to be hotter than the rads at the end of the circuit, by closing the valve you push the heat to the next radiator, this process is only needed if you have some cooler normal rads on the system.

It is safe as the worst you can do is switch off the radiators the fun part may be getting them back to where they were, to make it easier use your notepad and pen, count the turns it takes to close the valve, make a note of it and open the valve up to say within one turn of the original position, if the heat drops too much open it back to where it was.

One of the best ways to regulate the heat in each room would be to discuss fitting thermostatic radiator valves with your engineer when he arrives.
 
First off I agree with what some have said here, despite what mechanical engineering experience you might have setting up these burners to run smoothly, effectively, efficiently and safely requires someone fully qualified and experienced, by no means should they be tinkered with by someone half educated, regardless of how basic the concept appears to them.

All boilers require regular servicing and maintaining if there to run efficiently and safely, and on older boilers like that they should really be serviced every six months.
Efficiency is roughly 8% less to every 3mm of soot build up (you do the math)
With regards to the nozzle, like some have said reducing it's size is not going to make a difference. With the size of your system a .6 gallons an hour sounds about right but any professional engineer would be looking at the boiler manufacturers booklet (and if you don't have it then download it) and then checking the required size nozzle and settings for the burner for power output your boiler requires. These burners have to be set up accurately or you will have problems.

With regards to the cycling it could be a few things.
Starting With boiler:
. Any soot at bottom of flue indicates a flue problem, you could have a partially blocked flue retaining more heat within the boiler (servicing every two years means thats a strong possibility). Flue gases would eventually escape up the flue, the temperature would fall and the boiler ignites again.
.A faulty boiler stat is just as likely, set to cut power to burner when 60-65 degrees C is reached but is cutting out at 50 for example.
. It has been colder recently and when colder air is forced in for the combution process sometimes the flame is brighter and might burn a little hotter.
It doesn't sound like a problem with the burner because I would expect lockout, certainly not coming on and off every 3 minutes.
Inside house causes:
. An old pump on its last legs could be struggling to pump the heat away from the boiler quick enough.
. Air locks or partial air locks can cause the same problem, much like a system filled with black iron oxide (sludge) would as well, when the pump is circulating it will act as a magnet and suck in any sludge causing a restiction in flow and in turn heat away from the boiler.

Those are what spring to mind initially but like I and others have said these things are NOT toys and only someone who understands these things 110% and then some should be working on them.
 
Thanks guys,
An engineer called today to check out the boiler.
All good at that end thankfully.
Things mentioned.....
The 2 red taps ............
1 shuts off the feed to all the hot water taps, so told to leave open.
The other stops the hw tank heating, so told to leave open.
On my system I'm told the hw tank has to heat up whether you want hot water or not.
It all works fine but the boiler still cycles every few mins.
The chap suggested a cylinder stat may help.
when I switch the programmer to ch it shows ch and hw.
The rads get hot and the tank gets hot at the top half.
Am I right in thinking that the coil is in the bottom (cold) part of the tank and cooling the return temps so the boiler comes on again even when the rads are hot enough??
In light of this where on the tank should the stat be fitted?
At the moment the temp of the water in the actual boiler is dropping 12 degrees c in 3 mins after it switches off which seems a lot even in an old house, and cycling the boiler.
Cheers
Craig
 
Hi.

This is just to enlighten you a little on your system but you must call an engineer out to undertake any remideal work.

1.You should have 1 gate valve (red tap) on the cold fill from the hot water header tank to the hot water cylinder, this is to isolate the cylinder should it ever need to be drained down. There should never be any sort of gate valve on the heating circuit that will block off the vent for safety reasons.
2. From what you have just said your system is an old gravity hot water and pumped central heating, camrays were a thing from 20-30 years ago at a time when most systems were like yours. The boiler cycling is because of that sort of system, it always happens as long as the programmer is calling for hot water and when the programmer is calling for CH you will see the HW light on as well, thats how those systems are wired.
This can only be fixed by either having an engineer install the correct zone valve on the hot water return from coil with a cylinder stat to prevent boiler cycling or converting to a fully pumped system with thermostatic contol (which is what it should be)

When you take into consideration the age of your boiler and the fact that at best I wouldn't expect any more than 80-85% Net efficiency I strongly suggest you think about a complete system upgrade.

I've enlightened you on the cause of your issue so now is the time to contact a compitent engineer and discuss what your going to do. All I've said here is to inform you of the issue, I am not advising or suggesting you carry out any work yourself.
 
Thanks for taking the time to explain my system SJB6.
There is no way I can afford a whole new system in the next couple of years unfortunately.
Would you mind answering a couple of questions for me?
Does a fully pumped system mean the system would then be more pressurized?
I have been told that while my system is and old design as you mentioned it was quite a safe system with regards to pressure?
The reason I'm asking is that as I can't afford a new system I was wondering if going the fully pumped route would be massively more expensive than adding a zone valve and a tank stat.
I was kind of hoping I could get the guy back who checked out my boiler to put a tank stat on and the zone valve you mentioned as it sounds cheaper than going fully pumped, and would at least be an improvement would it not??
Cheers
Craig
 
Hi.

Converting to a fully pumped system means that both heating and hot water would be pumped, as it stands your heating is pumped and your hot water is gravity. When they are both fully pumped they would be thermostatically controlled, meaning once desired temperature is reached the boiler would shut down, preventing any cycling, which you have now. With regards to pressure your system is safe now just not thermostatically controlled, when pumps are used they do cause a slight incease in pressure but nothing to worry about, it's just the pump forcing heated water around the system.
Converting to fully pumped will be more expensive than just zone valve and stat because more wiring will be needed as well as pipework will need to be re-done so not to block off safety vent and/or get air entraitment (sludge).
Personally I think you should have a good engineer install the zone valve and stat now, that would atleast give you thermostatic control and prevent boiler cycling (won't improve boiler Net efficiency, just decrease the amount of fuel your boiler burns), then when you can afford an upgraded system (new boiler, oil tank, fully pumped heating system with thermostatic control etc) consult with a good engineer then (look into government boiler replacement schemes, you might find something your eligable for)

Side note : There are open vented and sealed boiler systems, both with their advantages and disadvantages, ask your engineer to explain further.
 
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ShaunCorbs
ShaunCorbs
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  • Question
What are the normal cycling temperatures of a boiler
I have a Glowworm Ultimate 35C boiler. It shuts off at its max temp of 60C when heating radiators and the pump carries on running pumping heat...
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Chuck
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