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Honeywell Wall Thermostat YTH9421C1010
This part YTH9421C1010 is compatible with:
- Product Type:
- Furnace, Humidifier
- Brands:
- Honeywell
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Wall Thermostat Customer Reviews
Common Problems Fixed by the Wall Thermostat
Based on customer reports and repair data, this part commonly fixes these issues:
Heat pump won't turn off
Furnace blower not running
Heat pump won't turn on
Furnace wall thermostat not working properly
Heat pump wall thermostat not working properly
Heat pump is frequently cycling/short cycling
Heat pump has poor temperature control
Furnace not turning on
Furnace not heating
Furnace blower runs all the time
Heat pump not cooling
Heat pump not heating
Heat pump compressor won't run
Furnace blower is running constantly but there is no heat
Furnace has poor temperature control
Furnace is frequently cycling/short cycling
About the Wall Thermostat
The wall thermostat has electrical contacts that send signal voltage back to the control board and the outside unit's contactor to run the heat pump system. If the contact that controls the contactor sticks closed, it will send continuous voltage to the contactor, causing the system to run continuously. To determine if the thermostat is defective, use a multimeter to test it for continuity. If the wall thermostat shows continuity between the red (“R”) and yellow (“Y”) thermostat wire terminals when the thermostat is in the “off” position, the thermostat has failed and will need to be replaced.
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