Low gas pressursay Gritish Bas All aspects of plumbing questions and answers, help, tips and information

[DamselinDistress]

Hi, I live on the 3rd floor of a block of flats. The pipes feeding the combi boiler are 30mm (2inchish). However, the boiler although working for the water seems to stop working for the heating. An engineer came and says I have low gas pressure. It is recommended at the boiler run 18 mbar gas but I have 15 mbar. Does anyone know what can be done? I am at my whits end at the moment as Gritish Bas could not fix the intermittent heating problem - or the heating just not getting as hot as it should. Is there a boiler that will run on low gas pressure?

Thanks ever so much.

[htg engineer]

If its a combi then they're talking rubbish, the boiler would run at a higher gas rate for the hot water. unless they mean the gas valve is working correctly.

I would get a heating engineer out to take a look. If you have BG package, cancel it - it's a waste of time all they ever want is for customers to upgrade their boilers.

The gas provider has a duty to provide a working gas pressure of 18 to 22 mbar. If the gas pressure is lower than this then it is their responsibility to upgrade the governor, gas mains or whatever is necessary. Call your gas provider (transco or whoever it is near you) and tell them BG has said the gas pressure is too low. I bet it's not

If the pressure loss is greater that 1.0mbar across the system (from meter to boiler) then it's your pipework at fault, as a rule of thumb the gas pipework should be 22mm (or greater) from meter to boiler (depending on the length of the run) 15mm would not be adequate.

[npascual@btinternet.com]

I have a similar problem. The gas pressure at the boiler is 'low' (i'm told about 17/18 mbar by the person who tested it). The piping from the meter to the boiler starts at 22mm width but ends up with 15mm (not sure where the change takes place). The existing boiler is old, and spare parts are an issue. What I'm struggling with is that, replacing the piping would be a costly nightmare (first floor flat - meter in the basement). Is there not a boiler on the market that can operate on slightly lower gas pressures such as the above? After all, the piping was obviously adequate when the previous boiler was installed?

[htg engineer]

The pipe will need upgrading to at least 22mm - don't just guess though, get an RGI to do the calcs. Many boilers were installed with 15mm direct from the meter and some with 22mm reducing to 15mm.

New boiler requires 22mm, there's no way round it, it doesn't matter what was adequate - the fact is it has to be upgraded for a new boiler.

htg