This is the error code definition from the owners manual for the thermostat.
E2" on temperature display Brownout condition or too low of voltage to thermostat. Double check wiring and check for
24 vac between R and C. E2 will clear 15 sec after proper voltage is restored.
You could have had a power glitch that could have caused the error code to come up in the first place. Check all breakers make sure proper voltage supply is going to the unit
then , check for 24 volts at the thermostat, between R and C ( marked on thermostat ).
If no voltage at the thermostat, check for 24 volts at the heater at the transformer> If main power is present but, no voltage from transformer then your transformer has failed. This would need to be replaced. Make sure all wiring is correct with no bare areas or wires touching each other.Be sure to check thermostat wires also.
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