Gas pressure drop

[Tristar]

Our Village Hall has about 25m run of 28mm pipe after the gas meter then a further 5m of 22mm to the kitchen combi boiler and a further 3m of 22mm to a gas cooker. About 6m into the 28m run a 22mm pipe is teed off for about 5m, and feeds a further combi boiler.
On a recent check with all appliances, including gas rings, on, the pressure at the kitchen boiler inlet was only 14.6 Mb (Meter outlet is 21Mb). Am I correct that according to the regulations we should still get 20Mb (1Mb drop) at all appliance inlets under these conditions?

 

[Dan Robinson]

Yes.

 

[Tristar]

Thanks Dan.

 

[gas112]

what size meter and what size combi`s

 

[dilalio]

And requires a commercial ticket.

 

[Tristar]

I am not certain of the size of boilers or meter, which looks the same as my own at home. One boiler is a WB 28i Junior combi supplying hot water to the kitchen and 7 radiators, the other is a larger Vaillant Thermo Compact, and heats 13 large radiators in the main Hall. The cooker is a commercial 6 ring cooker with oven.
What is a commercial ticket please? And what determines its requirement?
We do have a landlord's Certificate.

 

[dilalio]

Anyone who works on the gas side of the installation needs to have qualifications for commercial work and be registered with Gas Safe for such work. The size and capacity of the pipework has a much larger purge volume than domestic installations and poses a greater safety risk.

 

[gas112]

Really ?

 

[dilalio]

AFAIK

 

[Tristar]

Anyone who works on the gas side of the installation needs to have qualifications for commercial work and be registered with Gas Safe for such work. The size and capacity of the pipework has a much larger purge volume than domestic installations and poses a greater safety risk.

I can see our gas engineer disputing this if he is not so qualified, so I would be grateful if you could refer me to this particular regulation. TIA

 

[Terrywookfit]

Volume above .035M3.

 

[dilalio]

It's currently undergassed as per OP so could well be in commercial territory when put right!

 

[gas112]

undergassed out of interest in what way and what is causing it ?

 

[dilalio]

Remove cooker from the equation and re-test. Both boilers on max output and if working pressures are within limits then the installation cannot provide for the cooker, which is the only appliance that won't fire up automatically ?

 

[dilalio]

@Tristar what does your gse say about the situation?