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Hello, you could look for the high pressure and low pressure safety cut out switches, however if those are tripped there would be a *cause for that, and the cause needs be discovered and corrected before the system will run reliably.
A bad printed circuit cause will result in no error codes in some circumstances.
A lightning storm can destroy the printed circuit card, some other sensors and even some circuits inside the thermostat.
as these circuits are damaged, there is no predicting which functions will work and which will not work since there are an unlimited number of possible defects that can be created