glow worm 30ci overheat thermostat

Bleeding rads today, pressure dropped below 0.5 bar and triggered F05 fault. Located overheat thermostat but button not obvious if it was switching or not, no click, nothing didnt feel like it was moving.

rigged a test lamp as no voltmeter, removed switch, lamp lights across the terminals but not between a terminal and the front of the thermostat.

duff switch??

Should add that no power appears to be getting to the boiler. Was fine turned it off when flashed F05 then nothing on turning back on. Fuse or ovheat switch?

thanks
bbb

If its really a two terminal o/h stat then it should be low resistance when cold and not tripped.

Rather than fiddle about at mains voltage I suggest you remove it and test with a battery and torch or car lamp to avoid shock or damaging the boiler.

Are you sure its not a low water pressure switch?

Tony

i removed the switch from the boiler before i tested it. power wasn't getting to the boiler, cleaned the power switch and everything now fine.

bbb