Heating, Air Conditioning, Fridge, HVAC/Furnace doesn't kick in


Hi Jim,

We've got a Lennox Merit Series furnace and Honeywell programmable thermostat. On occasion over the last 4-6 months the furnace fails to kick in... the thermostat will follow the programmed schedule but the furnace itself doesn't come on. The blinking lights on the furnace indicate that it failed to ignite three consecutive times (no pilot light, electronic ignition). However it will start every time without fail if I simply turn it off and back on again (usually just flip the breaker).

So it seems to me that it's not necessarily a problem starting.  Could it be a problem with the thermostat? Some problem with the communication between them? (I recently replaced the batteries in the thermostat as well just in case)

Both the furnace and thermostat were installed in 2006.


You can twist the "R" and "W" wires from thermostat togeather by passing the thermostat, if the furnace runs all the time the wires are togeather you could assume the proublem is the thermostat.
The batteries are just for the display and clock.
The blinking light should tell you what the proublem is if you read the blinks right away, if you wait to long it may tell you something else.  

Heating, Air Conditioning, Fridge, HVAC

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Jim Barnhart


Fifty + years conditioning the air.


Answer questions about , residential and commercial. Answer questions about sheet metal fabrication. Fifty years plus experience. No answers for oil equipment, No answers for kitchen appliances, No answers for laundry appliances, I don't specialize in one particular area of the HVAC area, I'm more of a General Practitioner, Limited in refrigeration/

Hands on since 1950

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