Hi, I am in need of some help, I have a problem with my Worcester Bosch 240 boiler. I have already replaced the diaghram a couple of times, and the last time decided to change the complete diverter valve just in case this was causing my problem.

The Problem is that when running my hot water, (normally when running a bath), My reset switch trips sometimes once and at other times 15 times in the duration of my bath being filled.

Somebody suggested air lock in the heat exchanger (red container) which I have bled and with old diverter valve, there was some air. Now with the new assembly there isn't any air or anything coming from this valve.

Please can anybody shed some light on this problem.

Many thanks

Cliff

Cliff, March 2008

the prob sounds like the secondary heatex is scaled that is the white one with 4 pipes going to it a build up of limescale in the domestic water side is stopping heat tranfere and because the hot water sensor is not telling the gas valve to reduce preasure because the hot water isnt hot enough it overheats the primary side of the proses causing it to throw the button out

eric, January 2009

hi there the red canister is your expansion vessel it should be charged with air pressure from the car type valve typically about 0.75 bar this can be done car tyre pump ,this item allows for expansion in the system ie when it gets hot and cold

the system pressure guage thing on front of boiler should read 0.75 bar cold and between 1 and 2 bar when its running

sounds like you have an airlock in the system or a failed heat exchanger

regards

steve

steve, May 2008

hi... i seem to have cured my problem by opening the stop tap a little which has increased the overall water pressure to the boiler....have you tried this ??

Regards
Mike

Mike Farrey, April 2008

replace overheat stat and c/h thermistor. otherwise poor heat transfer between heat exchangers. scale , sludge.

combiking, March 2008