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ransley ransley is offline
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Default 1995 Pulse furnace

On Feb 25, 5:44*pm, zimpzampzormp
wrote:
1995 Lennox Pulse 21 furnace. Ironically I did everything from welding
the heat exchanger to assembling it to installing it in my house. I am
not an HVAC tech or an engineer.
The other day I noticed my second problem. A couple of years ago the
blower motor failed. Had to replace it with an upgraded motor as the OEM
was unavailable at the factory. Very successful operation. I also
replaced the air flapper as the old one was caked with dirt.
Last week I noticed it was short cycling. The purge blower would run and
the for about 5 seconds it would try to fire. Then it would go silent,
then the purge blower would run. Then the cycle would repeat. Anyway, I
found that if I have the thermostat set at 75 deg instead of the 68 deg
I usually run it at, it fires and cycles just fine.
Weird.
Before I call a real tech, does anyone think the problem could lie in
the electronic thermostat?

Thanks.


If it works fine and cycles fine set at 75 but not 68, replace the
thermostat