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canuck the pro
canuck the pro, Plumber
Category: Plumbing
Satisfied Customers: 2946
Experience:  Plumber and Handyman
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Mike I've got a biasi m90e28s Combi which won't reach any

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Hi Mike I've got a biasi m90e28s Combi which won't reach any hotter than 40 degrees on hot water. Any ideas?
Hi I am a Mike and possibly even the Mike you were looking for. I will be glad to help you today. Do you get any error code? When running a hot tap does the boiler stop firing or continue to fire when the water comes out "not so hot"?
Customer: replied 2 years ago.
Hello Mike no, no error code, the boiler doesn't show any faults, it runs fine but hot water will not reach any more than 40 degrees. The boiler doesn't go out out and is showing no signs of overheating it just won't go any hotter
Customer: replied 2 years ago.
I've checked for gas at the gas valve and there is 21mbar so not under gassed
Well that is very good. Likely an issue in the plumbing and the boiler is fine. Is the pump on the piping running? If so is it really hot? I assume the boiler is used for heating also?
Is this a new installation or older?
Customer: replied 2 years ago.
No it's an older boiler which has been working fine up until now so def not the plumbing, but any other ideas?
No, almost certainly the plumbing. It is likely either the pump is not pumping or a non-return valve is stuck open or a diverter is failing. The cold feed line for the hot water has a return line that connects to the cold inlet of the boiler. The pump pumps the hot water in the loop. If the pump has failed, diverter or non-return valve failed then when you turn on a hot tap cold water is drawn into the hot feed line and mixes with the hot water causing the water to be tepid. A really hot or noisy pump would indicate a failing pump. Otherwise the non-return valves and diverter would need to have a little exploratory surgery to confirm what has failed there.
Customer: replied 2 years ago.
Hi thanks for your reply, the pump is fine, I ran a resistance check and it's working fine(the heating gets hot quickly too and the water is circulating quickly enough) diverted seems fine too where are the non return valves exactly?
There should be one on the cold inlet before the connection of the return line and also the return line. Likely there is not one on the return line.
Cold inlet of the boiler.
Customer: replied 2 years ago.
Nice one thanks so much for all your help I'll give that a go. ­čśÇ­čĹŹ
Excellent. You can still comment and ask questions even after positively rating my service. I am happy to continue to help and I will always respond. Mike
canuck the pro and other Plumbing Specialists are ready to help you
Customer: replied 2 years ago.
Good man thanks! 5 stars coming your way!
Thank you!