Baxi main calling for heat fault

[ash1212002]

Baxi main combi 24 HE

Room thermostat is off, no timer is fitted to the boiler

The dial on the boiler is set to hot water only but the central heating radiators are hot

Noticed when running the hot water, the flame light comes on but when the hot water is switched off the flame light comes back on after a few seconds and puts the central heating on

Could this be the diverter valve?

 

[undertrained]

It could be a few things, if you’re gas safe registered please ask in the combustion chamber forum rather than public forum. If you’re not then please don’t ask for gas safe advice in an open forum as per the forum rules.

 

[ash1212002]

Not sure what the problem is asking here!

There are several similar posts on the open forum!

 

[ianmcd]

sounds like you have a faulty (either jammed or leaking) DHW Flow switch, when you drop the electric panel the divertor valve is at the bottom left hand side of the boiler, and the flow switch is at the front of the large round diaphragm housing, you should be able to tell by looking at it if it is made or has water ingress signs

 

[ash1212002]

sounds like you have a faulty (either jammed or leaking) DHW Flow switch, when you drop the electric panel the divertor valve is at the bottom left hand side of the boiler, and the flow switch is at the front of the large round diaphragm housing, you should be able to tell by looking at it if it is made or has water ingress signs

Thank you for the helpful response, will have a look and report back, much appreciated

 

[ash1212002]

sounds like you have a faulty (either jammed or leaking) DHW Flow switch, when you drop the electric panel the divertor valve is at the bottom left hand side of the boiler, and the flow switch is at the front of the large round diaphragm housing, you should be able to tell by looking at it if it is made or has water ingress signs

I've looked at the microswitch/flow switch, opening the tap the pin pops out, closing the tap the pin returns back into the neutral position.

Should i be hearing a distinct click when the pin hits the microswitch? as i didn't hear anything..

No signs of water ingress whatsoever either

 

[ianmcd]

then the divertor valve working correctly, isolate the power and pull one of the wires off the micro switch, turn the power back on with the wire isolated and if the boiler doesnt fire you have found the fault

 

[ash1212002]

then the divertor valve working correctly, isolate the power and pull one of the wires off the micro switch, turn the power back on with the wire isolated and if the boiler doesnt fire you have found the fault

This is a three wire microswitch the wiring is integrated into it

 

[ianmcd]

have seen that make of micro switch before , but not on a baxi so new to me, trace the cable to the PCB and pull the plug off and see it it stops the boiler false firing, Those micro switches can be very unreliable

 

[ash1212002]

have seen that make of micro switch before , but not on a baxi so new to me, trace the cable to the PCB and pull the plug off and see it it stops the boiler false firing, Those micro switches can be very unreliable

Apologies, it's a main combi 24 he
Gc 47 474 02

I'll trace the wire and have a look, I've ordered the microswitch

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/283089521782

 

[ianmcd]

that is not the same micro switch that was in your post and it will not fit

 

[ash1212002]

that is not the same micro switch that was in your post and it will not fit

I've had it confirmed with the seller that it is correct via the gc number, will have to cut the wires as the wiring loom has other connections and costs a bit more

 

[ianmcd]

well tell the seller he or she is talking shoite, your pic has a three wire microswitch, or hand shake micro switch as some of us call them, that switch only has two terminals and is the one I would have expected to be on your boiler, but if the pic you posted is of your actual boiler what are you going to do with the third wire ? and which two wires are you going to actually connect ? that part you have bought is the pump proving micro switch not the DHW flow micro switch they are not the same thing

 

[ash1212002]

well tell the seller he or she is talking shoite, your pic has a three wire microswitch, or hand shake micro switch as some of us call them, that switch only has two terminals and is the one I would have expected to be on your boiler, but if the pic you posted is of your actual boiler what are you going to do with the third wire ? and which two wires are you going to actually connect ? that part you have bought is the pump proving micro switch not the DHW flow micro switch they are not the same thing

There are three terminals on the new microswitch if you search the forum for part no 248207 this matches the ad. Also provided pic of original part to seller he has confirmed it is 100% right

 

[Hot&Cold]

There are three terminals on the new microswitch if you search the forum for part no 248207 this matches the ad. Also provided pic of original part to seller he has confirmed it is 100% right

It Its not a part from the manufacture,this is https://www.adlink.co.uk/main-combi-24-24he-dhw-micro-switch-selector-switch-pump-cable-248207

Is there a water leak near the pump proving microswitch ? it could have been previously repaired/historical