I have changed the thermostat and it still does the same thing. Last year we changed the sequencer and fixed it for awhile but it started the same thing this year. There is something blowing the sequencer. I olmed the heat strips out and it has two, they are good. And I am wondering if I have a bad relay. This system has one relay for the heat strips and one for the sequencer. Help on this project will be greatly appreciated.

A heat strip that is drawing to much current/short circuit as they can do sometimes when they sag can cause a sequencer to go bad.

Also a sequencer that does not have the capacity for the heater it is servicing IE to low of a amp rate.
Loose connections also burn out many sequencers also. This causes overheating and failure.