Acceptable gas pressure drop between meter and boiler?

Discussion in 'Plumbers' Talk' started by Gordon S, Apr 10, 2008.

  1. Gordon S

    Gordon S Member

    The boiler does seem to work OK generally. I had a 24kW Baxi combi in my last house (fitted about 5 years ago) and wasn't that impressed by the performance, so for my new house I asked the installer to provide the most powerful wall hung available from a good manufacturer. If I am honest, the speed at heating up the water and CH don't seem significantly better than my old Baxi, but presumably this might partly down to lack of working pressure. Perhaps the boiler is losing a few kW of performance because of lack of working pressure?
    It may be my imagination, but the CH and DHW appeared to be giving much better quicker heating since Transco managed to give me an extra 2mb.
     
  2. Mr Ian

    Mr Ian New Member

    Get em back ASAP, with a kindly reminder that if they're not there within the hour it'll be a call to CORGI :)

    A 1mb drop is acceptable with ALL appliances running, 3mb with just the boiler is not. And all for the sake of a few m of 28mm pipe.

    Should never have been commissioned...
     
  3. there is alot if misinformation on this thread. Much of it comes from people who are not registered but some comes from people who are!

    Perhaps the saddest part is than several registered people were unable to understand what you had explained hence all that confusing your pressure drop with a leak!

    The simple situation is that CORGI will come free and measure the pressures and then serve adefects notice on the installer requiring him to replace the pipework with the correct size to ensure only a 1 mB drop from meter to appliance with all other appliances on.

    The work to meet the requirements of the Defects Notice must be done free by the CORGI otherwise he will lose his registration!

    Thats the problem, so many think they will get away with undersized pipework. But its really the householder who is to blame because we all know the cowboy who does not upgrade the pipework will get the job because he is cheaper and if he is not registered then there is no CORGI to force him to do it properly.

    Tony
     
  4. Water Systems

    Water Systems New Member

    The 30, 37 and 42 CDI all have 30Kw output to CH - it is toned down for 42CDI. That is why you see no difference in CH warm up. The 42 has 42kW to DHW. You may be able to uprate the gas rate to CH if need be. See W-B tech dept.

    The warm up of DHW from cold will be about the same. The lag is the proving mechanism of the burner controls, which is the same on all combis. A small integral water vessel reduces this on some combis, or installing a pumped secondary circulation loop.
     
  5. Water Systems

    Water Systems New Member

    there is alot if misinformation on this thread. Much
    of it comes from people who are not registered but
    some comes from people who are!

    ..and a lousy installation by a CORGI man too.

    This one is blaming the householder for the ***kups of CORGI men, who the householder trusted to do a professional job. This one has brain damage.

    ** snip the rest as it adds no **
    ** value to the problem in hand **
     
  6. Gordon S

    Gordon S Member

    Thanks Tony, Ian and WS.

    I just spoke to the Proprietor and his tone was not exactly helpful. The company are prepared to pop back next Monday or Tuesday and "take a look".

    Thanks for all your help. I really appreciate knowing what I should have been given. It wasn't a cheap job in the first place and the cost of the new gas run was significant on top of it. It's not like they fitted the new run as a gesture of goodwill.

    I think it may be just as well to get CORGI out for free to review.
     
  7. Water Systems

    Water Systems New Member

    Thanks Tony, Ian and WS.

    I just spoke to the Proprietor and his tone was not
    exactly helpful. The company are prepared to pop back
    next Monday or Tuesday and "take a look".

    Print off my post on the problem and print off pages on gas pipe sizing link. Give them all this and tell them to do it properly as I laid out. You have problems without the hob being on, when on you will have big problems. <u>Get the hob supply back to the meter.</u> Have the boiler on its own dedicated supply. The test should be with the boiler and hob on.
     
  8. Gordon S

    Gordon S Member

    WS - could I reasonably (or legally) have expected them to run the hob supply back to the meter as part of the associated works of having installed this particular boiler? The hob 'T's off the 22mm pipe just before it meets the boiler.

    I feel like letting them attend, either do the work (or not if that's their considered opionion) and then get CORGI's view.
     
  9. devil's advocate

    devil's advocate New Member

    I suspect that, even tho' WS's suggestion of taking the hob pipe back to the meter is good practice, you cannot 'force' them to do it - provided the pipe run they install will cope with all the loads running on 'max' simultaneously. This can be worked out with the pipe size calcs (and you'd need to add the future gas fire, altho' as said previously, this is unlikely to make a huge difference - however, if the set-up is borderline, then the gas fire could 'tip' it over the wrong edge...)

    You could, however, make it clear that any changes they make to the pipework will be tested with all loads, and that if there is an unacceptable drop in pressure at the boiler, they'll have to come back. This might make them want to cover themselves properly with this visit.
     
  10. Gordon S

    Gordon S Member

    Sounds a fair idea Devils Advocate. I will naturally give them first refusal to resolve the problem. I think I will also get CORGI out to review after the remedial works are done to satisfy myself.
     
  11. Water Systems

    Water Systems New Member

    WS - could I reasonably (or legally) have expected
    them to run the hob supply back to the meter as part
    of the associated works of having installed this
    particular boiler? The hob 'T's off the 22mm pipe
    just before it meets the boiler.

    The test should be with all appliances fully on - the hob takes a fair whack of gas too. To tee off at the boiler you may need 28mm virtually all the way.

    Common sense has to come into it. Through experience those in the know always have dedicated gas supplies back to the meter. There could be a glitch in the gas mains first thing in the morning or at half time during the cup final as the combis are all switched on at the same time. Also Transco (or National Grid) are cheapos. They install cheap second rate Spanish meter regulators, which are slow to react after being idle, and unless pressed will not upgrade the meter inlet with a 1"x1" maintap and 1" flex inlet.

    Having had some disputes with Transco, I ordered a new better quality regulator, inlet flex and larger maintap and changed it myself to solve a problem, as it was costing too much in return calls back to a job, as they would not change these parts, saying all was fine. It was cheaper to pay for the parts because of lost time and it all worked after. I bought Transco a meter regulator.

    I feel like letting them attend, either do the work
    (or not if that's their considered opionion) and then
    get CORGI's view.

    Just print off what I wrote that sums it all up. If they follow all tat they will not have any more calls backs and all are satisfied after. If they cut back and take the hob off the boiler supply pipe, say half way down the run, they be back again.

    Get them to test with "all" appliances fully on before they leave.
     
  12. devil's advocate

    devil's advocate New Member

    Hi Gordon.

    I understand that, in any situation like this where a trades-peep has done a job that isn't up to standard, you must give them an opportunity to put things right first (unless, I guess, they have shown themselves to be sooo incompetent that you couldn't reasonably be expected to allow them back into your house again...).

    Ie: you cannot simply get someone else to 'fix' it and then bill the original company, without giving them a chance first.

    I'm a bit concerned at their reaction tho'; you've had your boiler disconnected by W-B due to inadequate pressure, you've had Transco out to check over the alternative causes, and the Corgi comes across with a tone that's 'not exactly helpfull'! Jeepers.

    Sounds like you need to be calmly insistent...

    Good luck!
     
  13. Captain Leaky

    Captain Leaky New Member

    It certainly does sound sub-standard. I agree with DA, you must give the original installer the opportunity to put it right.

    If you just go elsewhere to fix it the original installer is probably justified in not paying up as he has not been given the chance to fix it.

    Of course - you may not want him back but if you cut all ties you also forgo the chance of him fixing the job for free.

    If you do go elsewhere give Paul Matthews a call, he is an excellent heating engineer.
     
  14. Gordon S

    Gordon S Member

    I will certainly given the company the chance to put it right. As a Contractor myself for the last 14 years(commercial kitchen ventilation systems), I know mistakes happen but we always put them right at our cost and our inconvenience. Mistakes happen!

    Any help I can give anyone on the regs of ventilating a commercial kitchen & gas interlocking to fans etc. pls ask!

    Thanks for everyone's help. I will keep you informed of the outcome.
     
  15. Water Systems

    Water Systems New Member

    he is an excellent heating engineer.

    You mean fitter, not engineer.
     
  16. screwhard

    screwhard New Member

    I,ve got a degree mechanical engineering,still call me a fitter.Whats your problem?
     
  17. oliver1234

    oliver1234 New Member

    he is an excellent heating engineer.

    You mean fitter, not engineer.

    I disagree with you here WS (and I don't always by the way).

    An engineer is someone who does engineering in the same way that anyone who does plumbing is a plumber or someone who rides a bike is a cyclist.

    It has no legal definition in this country and unlike "Doctor" or "Solicitor" anybody can call themselves an engineer.

    I am a qulaified spark but worked for years in the alarm industry, we were always reffered to as engineers not fitters because many of us didn't actually fit alarms we just repaired and maintained them.

    Last Saturday I was a heating engineer and this weekend I am going to be a joiner on Saturday and a plumber on Sunday. On Monday I will go back to my mundane life of being an IT Analyst. (whatever that actually means)!!
     
  18. Captain Leaky

    Captain Leaky New Member

    Walter = plonker
     
  19. screwhard

    screwhard New Member

    Walter = plonker


    Walter= Egotistical piece of diarrhoea;)
     
  20. Captain Leaky

    Captain Leaky New Member

    Walter= Egotistical piece of diarrhoea ?

    More like an uncontrollable fountain of diarrhoea :^O
     

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