While you wait for answers, we may have found some information which could help you.
Click here for Stopped Heating FixedName of front button plastic cover on microwave to replace?
How do I fix a Belling BEL-CJ/S525?
my belling microwave does not heat up?
User instructions?
belling microwave oven will not heat after swithing on with no food in?
Belling Microwave BEL CJSS25 no longer heating food?