Boiler stat failure (where the boiler continusly fires as the stat microswitches are stuck.fused in the on position) only happens when the power is ON at the programmer. It happens at my brothers house and has done since last month, which causes water to reach about 100 degrees and pump over via the vent pipe. water is the pulled back intot eh system via the cold feed. If i turn the stat knob down to 0 it still happens, i did this to makre sure it was def. the boiler stat at fault.
This process contunues every 5-6. it happens now for hot water. boiler is potterton flamingo II, wall hung, flue out horizontally through wall behind it.
I was thinking though, how does this happen, as surely the cylinder stat (or room stat if heating was on, not at moment though as it's summer)! would be satisfied and cut out power to the boiler (break the circuit) to the switched live terminals before it got to 100 and pumped over??
my second part to my post, is it easy to replace a boiler stat/are they hard to get hold of as the boiler is about 15-20 years old now.
thank you for reading.
This process contunues every 5-6. it happens now for hot water. boiler is potterton flamingo II, wall hung, flue out horizontally through wall behind it.
I was thinking though, how does this happen, as surely the cylinder stat (or room stat if heating was on, not at moment though as it's summer)! would be satisfied and cut out power to the boiler (break the circuit) to the switched live terminals before it got to 100 and pumped over??
my second part to my post, is it easy to replace a boiler stat/are they hard to get hold of as the boiler is about 15-20 years old now.
thank you for reading.
