Combi Boiler Gas pressure issue - Valliant 831

[ajc01]

i've just had a valliant 831 installed. The combi boiler is dropping (gas pressure) to around 13.5 when turned on. It's sitting around 21 when not in use and returns to this level post the drop to 13.5 after it has kicked in. The engineer will not certify it as it is dropping lower than the recommended level (21-17). What do i need to do here - next steps? Many thanks

 

[Corgigrouch]

The problem is for the guy who put the boiler in to resolve, so if the guy who refuses to register the boiler is the same gas fitter who fitted the boiler, then he should have calculated the correct gas supply for the boiler an included this in his price.. Unless you specifically refused a new gas pipe.. Errm he was CORGI registered wasn't he?

Of course it could be an issue with the regulator, in which case he should have tested the the working pressure at the meter, diagnosed the fault and duly contacted Network Gas for them to investigate the issue. if it is a dodgy regulator, then they will repair it free of charge

 

[ajc01]

I was only told at the end of the installation of the issue. I was surprised that I wasn’t informed earlier in the process of fitting it. He was Corgi registered. He mentioned at the end that the gas supply was insufficient to run the system. It needed to be running of a 22m pipe rather the 15m. He mentioned that he was hoping that the 22m join was closer to the combie and where the 15m came out. I’m disappointed that I have spent a lot of money on a good boiler and it ain’t working as expected. I wasn’t happy been told the outcome as I have wooden floors throughout the flat. What should have been the process for the bloke who fitted it.

 

[doitall]

This is exactly what I was arguing about the other day on this forum.

The cowboy chancer gives you a price, then all off a sudden the gas pipe is too small and he wants name your price to put it right., It's a rip off mate.

Well, two can play at that game so here's what I would do in your shoes.

Inform the guy in writing if necessary that he has priced to install a working boiler, e.g. a Valliant 831, and you expect it to comply with the regulations.

If that is not the case and he has cooked up then you demand he sorts it at his expense or deduct £500 from his bill, failing that phone Corgi. and tell him your going to.

 

[ajc01]

Thanks for your replies. They are helpful. When should have the fitter informed me of this in the process? Would of it been apparent to him b4 he fitted the boiler ie.by noticing that the gas pipe was 15m? I also had the system flushed and cleaned. Slight issue here as well. I pointed out a radiator that was turned off and has been for some time to the fitter. After flushing and cleaning there was very little waste. The radiator I pointed out was not working and when the boiler turned on, it remained cold but all the others heated up. I was told that the pin was dodgy or stuck/ broken. Would have this affected the flush and clean in any way?

 

[doitall]

Any reputable RGI would have known that 15mm would not be large enough for the boiler.

Unless it states in their quote that they may have to change it as an extra then, as far as I'm concerned it's included in the price.

Unless you supplied the boiler etc, then the quote will included all labour and materials, to install the boiler that complies with the regulations.

If however he was to say "look mate I messed up" you could perhaps meet him half way with the extra cost, provided you were happy with his work.

Other than that its his problem to make the installation Legal

If the pin is stuck then you can't flush the radiator because you need circulation, take the head off and gentle lift the pin about 6mm, then give it a squirt of wd40.

 

[Corgigrouch]

Yep... That rad wouldn't have flushed through and could still contain crud

Whenever I price a job, I always try to check the gas supply is adequate on my initial survey sometimes the gas pipe is hidden so I can only go by the pipework that I can see.. If there is any doubt, then I will price to replace the pipe... There is no guarantee that a 22mm pipe is enough depending on the size of the boiler (I rarely work with Vaillants so I don't know how big it is) and number of bends/elbows in the pipe run.

 

[Registered Gas Man]

15mm gas supply, funny..............

The muppet even if he didn't notice on his site visit (How I dont know) should have in formed you when started the job.

Just out of interest did you have a few quotes? If you did some of these must have mentioned a Gas Pipe upgrade and although the guy that did the work is now responsible you may be some what to blame taking the cheap option.

 

[Corgigrouch]

Just out of interest did you have a few quotes? If you did some of these must have mentioned a Gas Pipe upgrade and although the guy that did the work is now responsible you may be some what to blame taking the cheap option.

Hmmm Not sure that I agree with you there.. The price to install a boiler is a price to install a boiler that is safe and legal... Otherwise what is the point of us being Registered? My customers rely on me to ensure that every job that I attend is left safe... Be it working or not

 

[AlanE]

The engineer will not certify it as it is dropping lower than the recommended level (21-17). What do i need to do here - next steps? Many thanks

Did he leave the boiler working? In this situation the boiler should have been disconnected and labeled to the effect that it hadn't been commissioned.

 

[LUNAT]

HI

is he RGI?ask to see his card, take details and ring CORGI to confirm.He might be using 15mm as an excuse not to sign off the boiler

 

[gas4you]

Forgive me, but I have only just scanned through this topic quickly and got the general feel for it.

First off I would say your so called installer hasn't a clue about how to fit a Vaillant.

The inlet pressure reading at the gas valve will always be around 3mBar less than the associated inlet pressure at the point where your gas pipe is connected to the tail on the boiler. If there was a test point there you would see what I mean.

So this fact then makes your pressure equivalent to 16.5mBar, whilst this is stiil too great a drop across the carcass, it is none the less not as bad as he is making out.

The 831 should have its gas supply sized for 3.3m3/hr, which generally, making allowances for current pipe sizing tables not being that accurate, means a maximum of around 12M equivalent length of gas supply pipe to the 831, assuming it is the only gas appliance using this length of pipe.

If there are more then that makes the situation even worse.

I can only agree with the posts above, he should have ascertained the gas needed and sized the pipe accordingly, so unless he categorically stated in his written quote that a new gas supply my be needed but if it was, the cost was NOT included in the quote, I feel he should have to put it right to current regulations.

 

[ajc01]

Thanks all for the feedback. Another question; am I doing any damage running the boiler/system (anything)as it is currently working and what does it mean generally? Everything seems to be working fine and the pressure generally is a lot better via all taps and shower. As mentioned it, just drops to 13.5 before going back up to 21ish (and stays there). Don’t know if it’s worth mentioning, but it didn’t drop below this when all elements on the stove were going. It’s a 2 bedroom, 1 bathroom flat. Cheers

 

[gas4you]

If he has set the boiler up correctly for the stated co2 readings on full power, then although it does not comply wth the regs, it is not harming the boiler.

One point I would like to clarify. The dropping to 13.5 then coming back up to 21mBar. Is this when he is tesing at the gas valve inlet, or at the gas meter?

How do you know it is still doing this all the time unless he is there constantly

Could be a faulty govenor on the meter. NG will fix if so, but will need his details and CORGI registration when placing the call.

I take it you have these, or he will place the call for you?

 

[ajc01]

Thanks Dave. Good points. Yeap, guess I don’t know unless I am constantly there. It was getting tested at the gas valve inlet (underneath the new boiler and where the old boiler was - 15m) and not by the gas meter which is outside the front door. Hope that helps. Does that indicate that the flow into th flat is ok?