Intermittent boiler problem - Help please!!

1 Mar 2009
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United Kingdom
Hi I've got an intermittent problem with my boiler.

Its a Baxi Combi Instant HE and the hot water and central heating are not working, however this is intermittent at the moment - yesterday early evening, it wasn't working, then later on in the evening it started working again, was fine this morning and then stopped working just now.

I've bled the radiators and checked that there is pressure in the system, but when I switch the boiler on, although the lights come on for the heating and the hot water, the water is not getting hot and neither are the radiators. However, none of the fault lights are lit up either so I'm at a complete loss as to what to do.

There are lights which normally light up to indicate the water temperature, but these are not coming on at the moment. Any ideas as to what could be causing this?

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It sounds as if the system flow switch may not be operating.

If not then it could be dirt in the eye of the pump.

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It sounds as if the system flow switch may not be operating.

If not then it could be dirt in the eye of the pump.


If it was one of these, would the boiler not detect a fault and illuminate the appropriate led pointing to the pump :confused:
Hi all,

Thanks for your responses and sorry for lack of detail - I'm fairly clueless with this sort of thing!

The only lights that are on are the power light (12), and the central heating light (14), and then the hot water light (13) when I turn the tap on. The numbers in brackets refer to the attached picture (if I have attached it right!!).

Please let me know if there is any other information I can give that would be helpful - got a load of washing up to do and the missus on my back about how cold the house is!! :( [/img]
Could be an intermittent main switch problem, or a loose connection. Needs someone in front of it to diagnose.

The power to the boiler appears to be being stopped before the point that the pcb can detect a fault present and flash the appropriate led.
I am no expert here but wouldn't the safety/overheat thermostat be worth checking ?

I assume it is the thermistor type, and as long as you have a multi meter it should be easy enough to check.

WOW where did all those posts come from ?
Thanks for the replies so far - sounds like I'm going to have to get someone in to have a look at this then!

Just had a thought - we had our electricity meter replaced yesterday - could this have had an impact?

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