Baxi 100 HE overheats and melts heat exchanger - an explanation

[arran197]

I have re system boiler at the new house , boiler does not responded to thermostat knob and only cuts out on the high limit ..... thermistor reads 2.6 k ohms
high limit stats are on 0.5 ohms .... Burner pressure is 18.5 mbar
any one experienced this ?

Have you checked the inner door seals? The red seal crumbles away and the fan limit stat trips, throwing the over heat light. The boiler might not actually be getting that hot for the control knob to work.

 

[buckley plumb]

Have you checked the inner door seals? The red seal crumbles away and the fan limit stat trips, throwing the over heat light. The boiler might not actually be getting that hot for the control knob to work.

in worse case the burner can lift causing melt down

 

[SafeGasInstall]

I have cheked all burner seals and they are good . CO is 15ppm and ratio 0,0002
the problem I had was exp vessel lost pressure and I pumped it up and had a air lock in hex ..... All running smooth now 🙂