Gas and Oil Home Heating Furnaces - Thermostat only works on "Fan On"

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View Full Version : Thermostat only works on "Fan On"

ginglewood
11-11-02, 10:56 AM
Oil furnace is Lennox 023 series, approx 7 years old. Thermostat is Honeywell T87F2055 3 8639. Primary control is Honeywell R8184M. Furnace tripped breaker. When reset, furnace fires but fan will not come on with thermostat set to "Auto". It will come on when thermostat is swithced to "Fan On". In cooling mode it will work with thermostat on "Auto" setting.
What is this likely to be?

Ed Imeduc
11-11-02, 11:15 AM
Sounds like you lost the speed on the blower motor that was used for heat .This will only come on at the fan control in the furnace.When you turn fan on at the tstat or go to AC and call for cool that turns the relay on for another speed.Call an HVAC person I think you need o new blower motor;) ED
purger406
11-11-02, 05:29 PM
check out the fan limit that seems like that could be the problem:D