Fault on Baxi 105e Instant

davyboy10 · 18 Apr 2006

Hi, I have been trying to solve a fault on the 105e instant. Whats happeneing is when the boiler fires up to heat the hot water store, it heats the water up but then when you run a bath once the water store has run out then the boiler goes to a minimum flame around 2.0 m/bar and then eventually cuts out even though the water in the bath is still running. The thermistor has been changed along with the gas valve by someone previous to me but the problem still exists, they just cant fill a bath of hot water once the store has run out. Thanks for an advice.
Dave

corgiman · 18 Apr 2006

what temp differential are you getting across the primary's onthe plated heat exhanger?

maybe they are getting scaled up and not circulating correctly?

davyboy10 · 18 Apr 2006

Already flushed the boiler out with a descaling machine so I know its not that, any other ideas

ChrisR · 18 Apr 2006

Already flushed the boiler out with a descaling machine

buuut .... did you clean the plate heat exchanger??

Do do a search on these though - lots of tales of sticky bits and dodgy pcb's.

Baxmax · 18 Apr 2006

Poss. D.H.W Diff maybe,or not

Such Is Life

Soggy_weetabix · 18 Apr 2006

LISTEN TO THE CORGIMAN. He has nailed your fault

Regards

David

davyboy10 · 19 Apr 2006

ChrisR said:
Already flushed the boiler out with a descaling machine

Click to expand...

buuut .... did you clean the plate heat exchanger??

Do do a search on these though - lots of tales of sticky bits and dodgy pcb's.

I did clean the plate heat exchanger with a strong red descaler, I had the machine on it for 2 hours it doesnt take longer than that to sort it. The hot differencial valve is this a possibilty that the valve is sticking and not allowing the hoit water to circulate round the plate heat exchanger proper.
Dave

corgiman · 19 Apr 2006

Have you got a differential thermometer davy?

that will tell you what is and isnt circulating, as for the plated heat exchanger I have always found these a nightmare to descale properly and it would be just as well to check the primary circuit on it to make sure of circulation

also what ohms are you getting at the dhw thermister?

davyboy10 · 19 Apr 2006

corgiman said:
Have you got a differential thermometer davy?

that will tell you what is and isnt circulating, as for the plated heat exchanger I have always found these a nightmare to descale properly and it would be just as well to check the primary circuit on it to make sure of circulation

also what ohms are you getting at the dhw thermister?

I have managed to sort it out. I went back today flushed out the primary heat exchanger this time and after good 1 hours flushing i connected back up and the water is now staying constant on the 13.2 m/bar which it should read. After a while the gas pressure does flutuate down a bit but thats quite normal after running a bath full of water, the primary heat exchanger, thanks for your advice corgiman.
Dave

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Fault on Baxi 105e Instant

Soggy_weetabix

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