Can't get boiler commissioned (low gas pressure)

[Meme21]

Perhaps the gas supply to the boiler should have been at least 28mm ? 40kw combis generally need a hefty supply, personally I always install 28mm for anything this size, especially anything with a few bends in !

Hm - well the gas supplier installed 1" pipe. They told me that was as big as it could go as the outlet from the meter wouldn't take anything larger, and what do I know

If there isn't sufficient gas supply to the boiler what is the outcome of this? All I know is that I have a commissioned boiler and a warm house which is all I care about in the run up to Christmas. Should I consider getting it looked at again come the summer?

I never in my wildest dreams imagined that getting a new boiler would turn out to be so stressful and complicated!

 

[Meme21]

Meme

If your original quote from the RGI was not just for installing, but also comomisioning (1)- which reading the post I suspect it was- then you could reasonably approach him for recompense for all the investigation you undertook that if (1) was his responsability.

I was a little annoyed with him because when I gave him the information he became rather stroppy and suggested I should have told him sooner (as if I was wasting his time). I thought he should know such things as Gas Safe told me that RGI's all get the bulletins and he should know. I had only found out the day before and didn't at that time know that when he came back after the gas supplier had carried out their work, that there wouldn't be enough pressure at the boiler.

Oh well - it's all done for now and the house is warm

 

[transam]

some areas in the U.K suffer from low gas pressure , they are generally refered to as pinch points , I know of one such site , they suffer from low gas pressure , the most you can get at the appliance is 16 to 17 mbars ,in this case its got nothing to do with pipe sizeing , Corgi / gassafe are well aware of the prob , nothing can be done untill transco either convert the area to high pressure or renew the mains , the gas supplier does have a duty to maintain by law a min' gas pressure in the mains supply & as it was stated to me may not be 20 mbar ? in the early Biasi Prisma instructions 1998 , it stated Min inlet pressure at appliance running 15mbars .

 

[Meme21]

I am now a little worried. I have found a technical training bulletin issued by Worcester Bosch regarding supply pipe sizing. It says that i there is a run of pipe of 5 meters - which I have - with 5 elbows and 1 tee - I have nine elbows - then the pipe size should be 28mm. The gas supplier fitted 22mm pipe and moved the meter so this pipe is now my responsibility even though they fitted it.

The technical bulletin states: Ultimately, inadequate gas pressure can lead to an immediate dangerous situation.

What does this mean - and how dangerous and immediate?

I am now regarding my boiler as a lethal weapon. How concerned should I be?

I would be very very grateful for some answers to this

Val

 

[Corgigrouch]

Let me recap... You have a 40kW boiler, 22m pipe supplying it, 5 meter run to the meter, lots of elbows, and a tee off for either a gas fire or hob.. If this is the case, then I would say that your pipework is too small. I doubt that your 40kW boiler is giving you the 40kW that you have paid for and there is a risk that with the other applience running, the boiler could cause it to go out because the boiler has starved this applience of gas... When the boiler cuts off, then the supply will return to the applience which could allow gas to fill the room (Assuming that the appliance has no flame failure devices)... This is the dangerous bit.. It needs correcting

 

[Meme21]

Thank you for clarifying that Corgigrouch. I am absolutely appalled that both my Gas Engineer and the Gas supply people have just walked away from it. The Manager from the gas supplier came to see me - so he could have closure - and told me that he couldn't put a bigger pipe in and that anyway it would only give me an extra 0.5 mb of pressure so wasn't worth the bother.

I feel I have been taken for a ride, and am very angry with my gas engineer for not helping me in this situation. It has all been left to me to deal with and I am feeling a great deal of stress now. Surely it should be the gas engineer that I employed that should be the interface with the gas supplier not me as how am I to know what is correct and what is not.

 

[Steady]

I know someone who has been on the Worcester training day for installers and he reckons they will now let you 'get away' with 16mbar on their boilers though there is nothing in writing to confirm this obviously.

In this time of 42kw combis it is time the gas suppliers recognised the changing needs of their customers. I would be surprised if pipe size from the meter alone is responsible for your 14mbar. But some 28 pipe would be worth a try.

 

[holty]

basically worcester say if your meter is giving min pressure 19mbar, then your allowance of a 1mbar drop to the boiler on pipework.then theres a 1.5mbar drop on the GAS VALVE.then 16.5mbar is min pressure allowed.

 

[Agile]

I am surprised that several RGIs here are not apparently understanding the requirements or their responsibilities.

The gas supplier should supply 21 mB =/- 2 mB atb the outlet of the meter on full load ( of the meter rather than the boiler fitted. )

The installer should size the gas pipe to the appliance so that at full load ( including cooker and gas fires ) the pressure loss does not exceed 1 mB.

If your installer quoted for fitting a 40 kW boiler then his quote must include for doing it properly which is with at least 28 mm pipe for a 40 kW boiler. If he fails to do his job properly then you can expect him to correct his deficiency at his own cost or you can get gas safe to serve a defects notice on him.

We are taught and assessed on pipe sizing when taking the qualifications which we need to be registered so I would say he has no excuse!

Tony

 

[transam]

The gas supplier should supply 21 mB =/- 2 mB atb the outlet of the meter on full load

I would agree the gas suplier 'should' , supply gas at the meter of 21mbar
e.c.t , e.c.t , but is there any regulation that states , that it has to , ??
there is a regulation that states that the gas supplier must maintain a 'minimumn pressure , I have reffered to a C.I.T.B , gas training manual & it states , under statute British Gas must maintain a safe working gas pressure in the pipe at all times , & that pressure is stated as 13.5 mbars !!! Ultimately all installers assume that an adequate gas pressure , or supply exists or is obtainable at a customers meter , & in most cases they are correct , But on very rare occasions it is not the case !!

 

[gassafeman]

The gas supplier should supply 21 mB =/- 2 mB atb the outlet of the meter on full load

British Gas must maintain a safe working gas pressure in the pipe at all times , & that pressure is stated as 13.5 mbars !!

You work a cooker on that pressure. And why do British Gas have any say in the pressure?

Fragrant advise.

Paul.

 

[transam]

the term british gas , would now refer to transco , the problem that will or can occur is when an installer , installs a Pre Mix , boiler in a low pressure area , the Quantum heatsaver for example had or has a low gas pressure cut off device .

 

[gassafeman]

So, cooker?

Your happy it working on 13.5 m/b?

Dont spout crap about Transco, its not even Transco anymore.

Paul.

 

[mointainwalker]

meme

Since you now have a Tech Bulletin from the mftr stating that you need at least a 28 mm pipe for your circumstances my suggestion would be a recorded-delivery letter to either/both your gassafe installer and the gas supplier stating that according to the mftr's instructions ( and this carries a lot of weight in our ever-more HSE environment ) they have carried out an unsafe installation, and have potentially put you in "an immediately dangerous situation"

I don't know who this would be better addressed to - maybe others can advise - but your installer apparently hasn't covered himself in glory so far and cleared off asap, so perhaps good to drag him back and make him face up to the job he has been paid for.

There is a lot of hard advice here and you are obviously capable of collating the relevant parts yourself but it shouldn't be you struggling through all of this, hunting down service bulletins, so put the responsability clearly on the shoulders of a qualified professional, tell him to sort it and document everything.

Best of luck.

 

[transam]

Dont spout crap about Transco, its not even Transco anymore(gassafeman)

So alright its not transco , gas supplier than, if it makes you happy

Cooker were did I say I was happy about 13.5 mbars on a cooker , i've reviewed the citb manuual , & it actually states 12.5 mbars . sorry for the error I am merely presenting some figures , written by others , that some may find interesting , & contradict every thing that we are told e.c.t .