had it nearly 4 years only one prob (kept blowing fuses ) circuit board replaced under warranty, till now. when hot tap turned on boiler fires up as normal starts warming water then after about 40 secs trips out. its fine when the central heating is on . but sometimes its ok ! anyone help been told it could be ch thermistor situated above pump or possibly the diverter valve , any info appreciated before i send for the plumber !
Ravenheat csi 85t hot water probs
- Thread starter timritaharry
- Start date
If you leave the tap running does it ever re-light? If yes suspect sensor/s If no suspect Diverter valve function.
With a tap running and in a 'fail' state does the boiler light if you remove the ch thermistor wire? Its a bit tricky getting it off BTW. Decent pliers and a small screwdriver or something to bend the lug back slightly are often needed. This plastic lug often snaps off as well. Dont worry if it does.
This applies to earlier CSI's with 2 fuses on the pcb
as sods law will have it its working ok at the moment ! seems to work fine after the central heatings been on , but if left while were out at work fails then. will try the thermistor wire tonight, thanks.
pulled the thermistor wire, boiler wont run at all with plug removed , but once i've removed then replaced plug boiler seems to work ok ! ie its stops cutting out (till its not been used over night then its back to not working again ) as if something is being reset .
Its worth investing in a new thermistor 
If you fancy DIYing it then please make sure the boiler has cooled down when you replace it.
Instructions are in the manual.
If you fancy DIYing it then please make sure the boiler has cooled down when you replace it.
Instructions are in the manual.
have swapped both dhw /ch thermistors now appears to be working fine , thanks for your input. tim. 
Both are readily available from online spares companies or for the most expensive usually try www.partscenter.co.uk
If its 4 year old its the wet pocket type
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