Boiler "At Risk" - advice needed

Dave-S · Oct 10, 2014

I had a fault with a new-ish boiler (April 2013) which is under a 5 year warranty so the engineer comes out to rectify it. After he's done what he's done, he tests it including checking the pressure. Apparently it's 13 mBar and he announces that it's risky (the boiler apparently should be getting 16 mBar), gives me a official form and slaps a sticker on it. He measured the pressure at the meter and it was about 21 mBar.

He says I ought to get the pipes looked at as they are might be too small or old iron ones that are corroding. The problem is that the pipes are chased into the wall behind tiles. I am not sure how they get from the meter as the kitchen floor is concrete which is another concern.

I have dug out the commissioning sheet from the original installation which states that the gas inlet pressure was 19. I know nothing about CH systems so I presume that this is from the same place that the warranty engineer tested (i.e. where he found 13 mBar) and not the meter pressure.

Could the pressure going into the boiler have gone down this much in 18 months and if so what could have caused that ?

Desperately hoping I don't have to start pulling apart a fairly new kitchen which I have in fact also just decorated

Should I get my regular CH service guy in now ?

Cheers in advance

Edit: He did have me turn on all the radiators and all the gas rings but not sure if that 13 mBar measurement was before or after I did this

diamondgas · Oct 10, 2014

Always a grey area is this! 13mbar is pretty low however and to err on the side of caution At Risk is the way forward. YOU could continue to use the appliance but you do so at your own risk and need to know the risks and have it explained... Main risk is that it could cause problems with other appliances eg. your hob! In extreme cases it can cut off the supply to the hob allowing 'raw' gas to flow from the hob once the pressure rises! I'm assuming that the engineer did not deem the reduction in pressure so severe that it was cutting off the supply to the hob? They'd have capped the supply to the boiler and labelled it Immediately Dangerous, if it were?

Get your regular guy in for a second opinion and advise on possible solutions to resolve the issue.

townfanjon · Oct 10, 2014

I have a feeling the original 19 mbar wasn't correct.

Halesowen1 · Oct 10, 2014

Me too.

Ermintrude · Oct 10, 2014

Humm did it bench mark at 28kw have a perfect 35c rise too?

bigads28 · Oct 10, 2014

If he had you turn on the gas rings then it sounds to me like thats when he did that working pressure. Maybe the commissioning bloke didn't do that. If its 21mb at the meter then the pipe work is probably under sized. Is it possible to run a new pipe around the outside of the house?

Either way I'd call the original lad back and ask him how this has happened and to rectify it.

bigads28 · Oct 10, 2014

Ermintrude said:
Humm did it bench mark at 28kw have a perfect 35c rise too?

Perfect flow rate too..............surely not sir!! :sorcerer:

bright spark · Oct 10, 2014

I think you may have to repipe or get rid of gas cooker if running pressure is ok without cooker running. Whichever is cheaper, ye can't leave a boiler going with 13 mbar

AWheating · Oct 10, 2014

another example of poor workmanship putting people in danger it would seem. Undersized pipe i expect. What boiler did it replace?

i serviced a boiler recently and the gas rate on the benchmark said 56kw........ i thought wtf, i figured it out that the installer had added 28kw for the heating and 28kw for the hot water from the tech table in the front of the book 🙁 . The customer told me the manufacturer at risked the boiler on a warranty repair 1 month after the install due to a flue not being patched and falling. Customer said it was the cheapest quote.

kris · Oct 10, 2014

Dave-S said:
I had a fault with a new-ish boiler (April 2013) which is under a 5 year warranty so the engineer comes out to rectify it. After he's done what he's done, he tests it including checking the pressure. Apparently it's 13 mBar and he announces that it's risky (the boiler apparently should be getting 16 mBar), gives me a official form and slaps a sticker on it. He measured the pressure at the meter and it was about 21 mBar.

He says I ought to get the pipes looked at as they are might be too small or old iron ones that are corroding. The problem is that the pipes are chased into the wall behind tiles. I am not sure how they get from the meter as the kitchen floor is concrete which is another concern.

I have dug out the commissioning sheet from the original installation which states that the gas inlet pressure was 19. I know nothing about CH systems so I presume that this is from the same place that the warranty engineer tested (i.e. where he found 13 mBar) and not the meter pressure.

Could the pressure going into the boiler have gone down this much in 18 months and if so what could have caused that ?

Desperately hoping I don't have to start pulling apart a fairly new kitchen which I have in fact also just decorated

Should I get my regular CH service guy in now ?

Cheers in advance

Edit: He did have me turn on all the radiators and all the gas rings but not sure if that 13 mBar measurement was before or after I did this

I would say the original installer just measured either the standing pressure or he measured the pressure @ minimum rate, either way b4 the install he shouldve done a pipe size calculation , its quite scary how many guys are either missing it out with laziness or they simply dont know how to do it,