worchester bosch 240 boiler overheating

[ian1971]

worchester bosch 240 bolier, issue when it runs, pressure starts at 1,4 bar after it runs for 10 mins the pressure rises to 3 bar, the water temp & radiator temp is very hot (too hot to touch) then the boiler trips out, after an 1hr i can reset it and it will do the same thing, any idea's?

 

[kevindgas]

with that sort of pressure rise i would look at the expansion vessel it is probably deflated or perished.
if i recall the 240 and 280 have the calorifier in the front bottom of the boiler these get scaled up, a competent engineer should be able toremove it and descale it in an hour unless it is completely blocked.
they will need a replacement set of washers as the slide joint washers perish

 

[bengasman]

Have you tried setting the boiler-stat at 1? That should limit the output temperature to about 50C. If it is significantly more, the boiler stat is suspect.