While you wait for answers, we may have found some information which could help you.
Click here for Heater Tumble DryerHelp! my bosch classixx tumble dryer has x3 lights flashing and beeping!?
Bosch Classixx not heating even after trying red button reset ?
Bosch Exxcel 7 WTW863S1GB damp clothes, clogging filter?