My gas supply comes into the flat through the lounge (1 rad). Bedroom 1 is behind the lounge (1 rad). Then bedroom 2 (1 small rad – not working. then the bathroom (1*shower over bath + 1* towel warmer large). There is a narrow hallway that runs the length of the flat to the start of the kitchen (2*rads)Then the kitchen (1*rad / 1*gas oven (small)and hob (4 burners). I’d say there’s a main run in, the length of the flat with shots off (all poss 15m)
Combi Boiler Gas pressure issue - Valliant 831
- Thread starter ajc01
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Still is impossible to say.
If the boiler fires on DHW and the pressure starts at around 13.5 then whilst the boiler is still on full output goes back to 21 mbar, then I suspect the meter govenor.
If it fires on DHW then after a bit modulates down, then the pressure rises to 21 mBar then it sounds as though the gas carcass is hopelessly inadequate.
From your description I believe your gas carcass to be inadequate whatever the tests prove.
When testing the pressure the boiler needs to be set for max output, by pressing '+' & '-' together then getting SF6 reading in the display.
All of this points, from what you have said, that whoever has fitted this hasn't a clue about installation, or commissioning with an FGA. I take it one is being used
If the boiler fires on DHW and the pressure starts at around 13.5 then whilst the boiler is still on full output goes back to 21 mbar, then I suspect the meter govenor.
If it fires on DHW then after a bit modulates down, then the pressure rises to 21 mBar then it sounds as though the gas carcass is hopelessly inadequate.
From your description I believe your gas carcass to be inadequate whatever the tests prove.
When testing the pressure the boiler needs to be set for max output, by pressing '+' & '-' together then getting SF6 reading in the display.
All of this points, from what you have said, that whoever has fitted this hasn't a clue about installation, or commissioning with an FGA. I take it one is being used
I advised a customer who was having problems with an installer to contact Corgi because the gas supply going to an Ideal combi boiler (28KW as I recall)was only 15mm copper about 3mtrs or so to the boiler running off 1/2 MI externally up the side of the building from the gas meter and Corgi refused to get involved.
They said it was an issue for the manufacturer and that the gas supply was safe
However the boiler had about five manufacturer warranty calls in the first six months and they never commented re the gas supply.
BTW,you could see the entire gas supply from the meter to the boiler with the exception of the pipe in the external wall.
They said it was an issue for the manufacturer and that the gas supply was safe
However the boiler had about five manufacturer warranty calls in the first six months and they never commented re the gas supply.
BTW,you could see the entire gas supply from the meter to the boiler with the exception of the pipe in the external wall.
AJC, I notice that you have refered both to a "fitter" and to an "engineer".
I have this strong suspicion that you have had your boiler fitted by a non registered person who has called a CORGI ( illegally ) to sign it off.
I do hope that you have not paid for th installation work.
I suppose that you dont know the fitters name and address?
You should report the situation to CORGI who will come free and investigate the siruation.
Whatever you should not pay ANY MORE to get it corrected but that will not happen if you have already paid. You will not see them again and will find you only have a first name and mobile number!
Nor will you get the certificates you need.
Tony
I have this strong suspicion that you have had your boiler fitted by a non registered person who has called a CORGI ( illegally ) to sign it off.
I do hope that you have not paid for th installation work.
I suppose that you dont know the fitters name and address?
You should report the situation to CORGI who will come free and investigate the siruation.
Whatever you should not pay ANY MORE to get it corrected but that will not happen if you have already paid. You will not see them again and will find you only have a first name and mobile number!
Nor will you get the certificates you need.
Tony
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The OP has wood floors throughout. This could mean conventional T&G or laminate.
If the installer had specifically put in a disclaimer re the gas supply, because it couldn't be seen, then it is down to the customer to pay extra.
Can the OP confirm that there was no disclaimer? Also can the OP confirm that the installer left the boiler connected in this state?
If the installer had specifically put in a disclaimer re the gas supply, because it couldn't be seen, then it is down to the customer to pay extra.
Can the OP confirm that there was no disclaimer? Also can the OP confirm that the installer left the boiler connected in this state?
The boiler is safe to use as it has a minimum and maximum gas rate and is room sealed the performance of the boiler however could be comprimised and it is this that is the issue is not safety.I would expect the boiler to produce the correct kw at full rate ,if it does not then it has not been installed correctly and would expect the installer to rectify this at his own expense as you have paid for a maximum performance install
It is also worth mentioning if the installer was CORGI registered or not and who the "engineer" was!
What does the installer say about it?
Why dont you want to call CORGI to inspect the situation, thats free!
Tony
What does the installer say about it?
Why dont you want to call CORGI to inspect the situation, thats free!
Tony
Manufactures instructions will state gas supply should be of adequate size to supply 20 mbr at inlet.
Insuffcient inlet supply will void any guarantees on a new appliance.
On existing supplys if the gas pressure drop between the meter and inlet at the appliance is more than 1mbr, providing required pressure or gas rate is maintained this is not to current standards.
BUT THIS IS A NEW INSTALL.
If the installer has connected the appliance,tested and found a problem the boiler should not be in use until this is rectified.A warning notice should be issued and the boiler disconnected.
No decent installer would leave you with a problem like this.I agree this is a matter for corgi/Trading standards to take up..
Insuffcient inlet supply will void any guarantees on a new appliance.
On existing supplys if the gas pressure drop between the meter and inlet at the appliance is more than 1mbr, providing required pressure or gas rate is maintained this is not to current standards.
BUT THIS IS A NEW INSTALL.
If the installer has connected the appliance,tested and found a problem the boiler should not be in use until this is rectified.A warning notice should be issued and the boiler disconnected.
No decent installer would leave you with a problem like this.I agree this is a matter for corgi/Trading standards to take up..
hi,
i advised incorrectly here. The pressure when the boiler fires up goes down to 14.5. It stays here and doesn't go back up as i have previously stated. Does this sound like inadequate gas supply getting to the boiler and will replacing the 15m that runs off the main artery with 22m rectify the problem? Is there anyway of testing this pre implementing the change? The pressure at the boiler (when not switched on is around 21.5). What are the options here? Cheers again
i advised incorrectly here. The pressure when the boiler fires up goes down to 14.5. It stays here and doesn't go back up as i have previously stated. Does this sound like inadequate gas supply getting to the boiler and will replacing the 15m that runs off the main artery with 22m rectify the problem? Is there anyway of testing this pre implementing the change? The pressure at the boiler (when not switched on is around 21.5). What are the options here? Cheers again
I've had some issues with inlet pressure and have gone through a steep learning curve to understand what pressures are required at the boiler. I'm no engineer, but I have used this site to understand more about the requirements before I undertook expensive and inconvenient work.
I have a Vaillant 837 Ecotec and when recently serviced the gas inlet pressure (when on full demand) was 12.5Mb. The service engineer put this down to the pipe size being only 22mm, whereas he felt it should be 28mm. However he did also note the pressure at the meter (when the boiler was on full demand) was only registering 17mb.
This service engineer was not the same company that did the original installation, but when I spoke to the original engineer about this he indicated that when the boiler was commissioned it was fine. In fact he said that the previous boiler, which was situated about 4 feet away from the new one had old 18mm pipework and that was OK. He was right and I checked the service report on this and it was showing 17.5mb (on full demand). He suggested I get the gas pressure looked at coming into the meter before any work was undertaken.
That made me slightly suspicious of the new engineer's motives as he initially seemed reluctant that I get someone to look at the pressure at the meter. He even suggested that I should get the pipework changed first and then if there was still a problem I should call in National Grid! I'm no rocket scientist, but I'm also not stupid and know when I'm being spun a yarn!
I therefore used this site to increase my knowledge of gas pressures and discovered that National Grid are obliged (FOC) to ensure that pressure at the meter should be between 19 and 23mb (boiler on full demand). I therefore called them out before I undertook any remedial work on my pipework and they cleared a blockage and changed the gas governor.
The pressure at the meter is now 22mb (boiler on full demand) and the reading at the boiler is 18Mb - I know I've measured it myself (I know I shouldn't but it seemed the only way to satisfy myself). Although the 4mb drop from meter to boiler is a little above what an ideal installation would be, it's acceptable for the Vaillant 837 boiler, which should read between 17mb and 25mb when on full demand.
What I have learned from this is that my service engineer was far too quick to assume that the pipework from meter to boiler was defective. National Grid are more than willing to come out and look at things and makes some tweeks and this costs absolutely nothing at all.
In fact I also learned that the gas pressure at the meter varies during the time of the day and the weather. The colder the weather the more people that are using their boilers and the lower the pressure at the meter. Er go, the lower the pressure at the boiler.
Having said that, if I knew that 28mm pipework was standard when the central heating system was being installed then I would have said something, but you do rely upon the knowledge of the engineer and his experience.
I hope this helps someone else in a similar position.
I have a Vaillant 837 Ecotec and when recently serviced the gas inlet pressure (when on full demand) was 12.5Mb. The service engineer put this down to the pipe size being only 22mm, whereas he felt it should be 28mm. However he did also note the pressure at the meter (when the boiler was on full demand) was only registering 17mb.
This service engineer was not the same company that did the original installation, but when I spoke to the original engineer about this he indicated that when the boiler was commissioned it was fine. In fact he said that the previous boiler, which was situated about 4 feet away from the new one had old 18mm pipework and that was OK. He was right and I checked the service report on this and it was showing 17.5mb (on full demand). He suggested I get the gas pressure looked at coming into the meter before any work was undertaken.
That made me slightly suspicious of the new engineer's motives as he initially seemed reluctant that I get someone to look at the pressure at the meter. He even suggested that I should get the pipework changed first and then if there was still a problem I should call in National Grid! I'm no rocket scientist, but I'm also not stupid and know when I'm being spun a yarn!
I therefore used this site to increase my knowledge of gas pressures and discovered that National Grid are obliged (FOC) to ensure that pressure at the meter should be between 19 and 23mb (boiler on full demand). I therefore called them out before I undertook any remedial work on my pipework and they cleared a blockage and changed the gas governor.
The pressure at the meter is now 22mb (boiler on full demand) and the reading at the boiler is 18Mb - I know I've measured it myself (I know I shouldn't but it seemed the only way to satisfy myself). Although the 4mb drop from meter to boiler is a little above what an ideal installation would be, it's acceptable for the Vaillant 837 boiler, which should read between 17mb and 25mb when on full demand.
What I have learned from this is that my service engineer was far too quick to assume that the pipework from meter to boiler was defective. National Grid are more than willing to come out and look at things and makes some tweeks and this costs absolutely nothing at all.
In fact I also learned that the gas pressure at the meter varies during the time of the day and the weather. The colder the weather the more people that are using their boilers and the lower the pressure at the meter. Er go, the lower the pressure at the boiler.
Having said that, if I knew that 28mm pipework was standard when the central heating system was being installed then I would have said something, but you do rely upon the knowledge of the engineer and his experience.
I hope this helps someone else in a similar position.
You only 'appear' to have a 4mBar drop, in reality with your ecotec plus loosing 3 mBar betweenthe boiler gas cock and the inlet test point on the gas valve, you have the required 1 mBar drop.
Sounds like a lazy toad to me. Anyone servicing a gas appliance should call NG in if the WP at the meter is outside the accepted range.
(Before anyone says anything, yes I know this is a resurrected post from nearly a year ago
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A Vaillant 831 34kw boiler in a 2 bed 1 bathroom flat is completely mad, its like putting a jet engine in a mini!! it will pull 34kw for a few seconds and cut out from over heating- you'll never have enough demand on the boiler to satisfy the temps, you need a 15-24kw boiler.
Oh dear, someone didn't read the bright red message at the bottom of this topic telling them this topic is over 7 years old and doesn't need adding to, did they? Welcome to DIYNot, please try not to drag up ancient posts which have been long since resolved
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