Honeywell RTH221 Series Quick Installation Manual page 2

Identify System Type
This thermostat is compatible with the following systems:
Gas, oil or electric furnace
Central air conditioner
Hot water system with or without pump
Millivolt system
Central heating and cooling system
Heat pump without auxiliary/backup heat
Do you need assistance?
We are here to help.
This thermostat cannot be used on heat pumps or on
multistage systems.
69-2606ES—01
Call 1-800-468-1502 for wiring
assistance before returning
the thermostat to the store.
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