Rads too hot to touch

[richard3009]

Worcester Heatslave 20/25 oil fired boiler 4 years old, diverter valve renewed 3 months ago.

I don't seem to have any control over my radiator temps they get seriously hot too hot to touch, not sure if boiler c/h stat is working how can I check, I have turned it fully down and it has no impact on the rad temps, I thought if it failed the water would boil and fetch out the over-temp trip, or is my room thermostat catching it before it boils?

Could I test it by shorting out the room stat and seeing if the boiler boils, or is there a better safer way?

 

[Bartdude]

I test with my digital thermometer clamped on to the flow pipe and adjusting the dial. If it had failed completely then the O/H stat should operate,it may have gone out of calibration.Is the sensor properly located in the pocket?