Midasman; Temperaturecontrolman is correct with the trombetta relay being bad. It is mounted above the batteries on the wall with large red cables attached to it. He is also right that the replacement should be one with silver contacts. Google trombetta for a phone number and they will put you in touch with a distributor in your area as they will not sell directly to you. I had the same problem and after taking the relay apart and cleaning the contacts it still only worked for a short time. Replaced the relay with a silver contact one and have had no more problems for 4 years.
Blessings KDK
