After reading 25 pages of the Oven Building forum, I haven’t come across this idea…..We all love the smooth operation of an SSR..what with no lights dimming, contactor clattering, and perfect temp control. The only negative I’ve seen is if an SSR fails it can fail in the closed (ON) condition, which may be a safety issue.
Why not add a contactor after the SSR that is activated thru a small relay’s NC contacts when the oven is switched on? Then you could use one of the PID’s alarms to energize the relay and then open the NC contacts- deactivating the contactor if the SSR fails and an over temp condition is sensed. Seems to me it would be the best of both worlds….and the contactor should last almost forever with it only cycling once per operation. Or am I missing something??? For those of you that haven’t experienced the joy of an SSR- man are they cool. My oven easily holds temp within ONE degree.