Gas supply pressure fluctuation??

[rarara]

A few nights ago it was noticed that it was impossible to get the bath to fill hotter than lukewarm. Next morning was similar, but before and since its not been an issue.

Is the gas supply prone to pressure fluctuations - could that explain it? The gas fire was also on, and while running the water it dropped to barely a flame - this is normal but it seemed more pronounced that evening.

The boiler is a Worcester 30KW combi, but is otherwise fine.

I did happen to notice that the pipe from the gas meter starts in 15mm - I was surprised as all the visible gas piping in the loft leading to the boiler is 22mm. Should I be looking to get the whole run in 22mm - could it be contributing?

 

[Dan Robinson]

Your gas supply is undersized and therefore more susceptible to any local fluctuations.

Your fire should not drop when the boiler fires. This is potentially dangerous..

 

[FiremanT]

A few nights ago it was noticed that it was impossible to get the bath to fill hotter than lukewarm. Next morning was similar, but before and since its not been an issue.

Is the gas supply prone to pressure fluctuations - could that explain it? The gas fire was also on, and while running the water it dropped to barely a flame - this is normal but it seemed more pronounced that evening.

The boiler is a Worcester 30KW combi, but is otherwise fine.

I did happen to notice that the pipe from the gas meter starts in 15mm - I was surprised as all the visible gas piping in the loft leading to the boiler is 22mm. Should I be looking to get the whole run in 22mm - could it be contributing?

Gas supply pressures can fluctuate to a certain for a variety of reasons. However, the clue to your basic plight is the fire flames normally reducing dramatically when the boiler fires. They shouldn't. Your internal gas supply is seriously undersized, amd may even need some 28mm.
It may be that the hot water heat exchanger is starting to scale or get dirty. The poor gas will excacerbate this problem I am guessing that if the gas is so bad, the system wasn't cleaned before fitting the new boiler

EDIT: Dans post is a bit more concise than mine, but I had stopped for 20 mins or so before completing and submitting

 

[rarara]

thanks for the advice guys - will get my plumber to have a look at potentially replacing the 15mm with something larger in the first instance

 

[Agile]

Better to get a gas registered person!

Ask him to measure the pressure at the meter with all appliances running.

Then to advise what to do to ensure all the pipe sizes meet the correct requirements.

Just asking him to replace something may still end up with something dangerous. Even more so if he is not gas safe registered!

Tony

 

[rarara]

he is, and i had assumed he would do proper checks before recommending that course of action