Is the engineer aware of this fault?.Get him back in and explain your findings.providing the dryer is not clogged with lint,he can bypass the thermister to check its operation.Even new T/stats can be faulty,.He will now know if there is a problem with the heater relay on the pcb.A new pcbcosts around £100 or you can by a reconditioned unit for around £40 its a exchange service.
paul, January 2012
