Issue
Erie T200 series thermostats, display is blank, or thermostat will not hold setpoint, or thermostat function buttons do not work.
Environment
Erie T200 Series
Cause
Bad or missing thermostat battery.
Resolution
Replace the bad or missing thermostat battery p/n Energizer 357 or equal. Confirm voltage is between 20 and 32 VAC with 75mA to 1.2A of power is available. If the battery is good and voltage and current is within specification then replace the thermostat.
Symptoms
Display fades away after 1 minute then goes BLANK. No function with up/down buttons.
SETPOINT will default to 70°F (21.1°C) in Heat mode and 76°F (24.4°C) in Cool mode when power is restored.
If the thermostat was manufactured before 2000, the default was 75°F (23.8°C) for both Heat and Cool mode.
With a good battery, the display will indicate space temperature.
There are no functions with the up/down buttons.
The last setpoint is maintained when power is restored.
