Gas not powerful enough?

[pogologo]

Hope someone may be able to give me some direction on this. I have a Powermax 155 fitted and have been getting quotes for a new combi install. A few of those quoting have stated that we will likely need a new gas pipe running from the mains as our current feed won't be powerful enough for anything greater than approx a 30k WB.

We already have a 22mm running to the current appliance.

Does this sound correct? Haven't heard of not powerful enough gas before!

What will happen if it isn't powerful enough? Is there a way of testing the power?

Thanks

 

[kevplumb]

Does this sound correct? Haven't heard of not powerful enough gas before!

no such animal

it depends on the calculated length of the pipework

you should have 20 mb working pressure at the appliance inlet under full load

if the appliance you are considering fitting uses more gas than the existing pipework can supply

it will need to be upgraded

it's called doing the job right

 

[D_Hailsham]

It's nothing to do with the power, but the gas pressure at the boiler. The pressure at the gas meter is controlled by the regulator on the top. However it drops along the pipe from meter to boiler, due to the friction in the pipe. The drop will depend on the flow rate (which is proportional to the power of the boiler) as well as the size and length of the pipe, and the number of bends in the pipe. The pipe must be sized so there is no more than 1mB drop along the length of the pipe.

You have to take into account all the gas powered devices in the house when sizing the gas pipes.

All the installer is saying is that you may need a larger diameter gas pipe.

 

[HotrodCJH]

It is quite normal to have to upsize the gas when installing a new boiler. If the boiler is going to be around 30kw and it is not close to the meter, you will more than likely have to up to 28 or 32mm.

 

[mysteryman]

This is all very pessimistic. A competent installer should be able to calculate whether the existing pipe is big enough. 22mm could well be OK.

 

[JohnD]

you haven't said how far it is.

... our current feed won't be powerful enough for anything greater than approx a 30k WB.

For a Combi, why might 30kW not be enough for you?