Boiler overheating

dantheman2010

Good afternoon all,

Perhaps a silly question but what causes a boiler to overheat?

I have a Baxi Solo 3 PFL 40 which is about 5 years old, we have the timings as follows;

HW & CH
6am - 11am
5pm - 11pm

This morning the LED was on OVERHEAT and BOILER ON so I turned the knob/dial to zero and back and it was fine (as per the instructions) but this is the second time in 2 weeks it has happened, just curious as to why it would overheat?

Thanks

har0ld

Is the rad used as a bypass turned off or does it have a thermostat on it when it shouldn't?
Many boilers need the central heating circuit to remain flowing and if all rads switched off - no flow - then may overheat. - hope this helps

dantheman2010

All rads should be on - well they all heat up when CH is on, so they are definitely all on.

Had a new motorised valve fitted in July time. Not sure if that helps.

ormus

boiler stat may be faulty.
the new port valve may be faulty/sticking.
or wrong port valve may have been fitted.

dantheman2010

ormus wrote: »

boiler stat may be faulty.
the new port valve may be faulty/sticking.
or wrong port valve may have been fitted.

Boiler stat - what is this?
New port valve hasnt had a problem since July (fair enough CH hasnt been on much in that time but HW has been fine since changing).

gas4you

Common fault on these is the pcb. This controls the pump over run (approx 5-6 mins). If the boiler is hot, the controls tell it to switch off and the pump over run does not operate, the boiler will go to overheat.