Baxi 80e combi boiler ignoring room thermsotat

17 Aug 2004
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United Kingdom

I've just moved into a property with a Baxi Combi 80e gas fired combi boiler.


Although this is quite an old and discontinued boiler and not the latest efficiency it does seem to work OK for both HW and CH. However, it seems to completely ignore the room thermostat and just work off the timer (or run constantly) depending on the position of the switch on the timer.

The thermostat still 'clicks' at the current room temp (or thereabouts) but the boiler seems to continue firing until it reaches the internal HW temperature as required by the dial on the boiler, even if the thermostat is 'off'.

I've now got the boiler CH temperature dial set quite low (80+ deg C seemed excessive for the radiators anyway despite the manual suggesting to keep it on max in winter).

Does the boiler's internal temp requirements override that of the room thermostat? Or is it likely just a bad connection to from the thermostat to the boiler?

So for example if I have the boiler's CH dial set way up to 80 degrees, will the boiler continually heat the water and then pump it round the radiators at that temperature even if I have the room thermostat set at 10 degrees C and hence not calling for heat? Or should it just shut off the boiler in that case, until the temp drops.

(I know - or thought I knew - how a room thermostat worked with a boiler so this does sound broken, but I'm just checking.)
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How many wires go into bottom of boiler 2 , or 1 thinish one or 1 thickish one ?
Sponsored Links
How many wires go into bottom of boiler 2 , or 1 thinish one or 1 thickish one ?

Just the one mains power cable connecting under the boiler and then the standard gas and water pipes. So sounds like it's just not connected. Not even sure where the wire from the room thermostat is - few things look a bit fishy though. I've got a free check coming up soon so will get the engineer to take a look. Fortunately I've found a CH temperature on the boiler that seems to regulate to the room temp we'd want anyway so hopefully we're not pouring too much extra cash away - and it will be summer soon :D

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