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hr(bob) [email protected] hr(bob) hofmann@att.net is offline
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Default 1995 Pulse furnace

On Feb 25, 10:00*pm, ransley wrote:
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- Hide quoted text -

- Show quoted text -


If it is a pulse type, trash it. My neighbor's only lasted about 3
years before he had to replace it.

I still have an old 1965 gas-fired furnace where the flame is ignited
by a pilot light and burns inside a great big can. It may be old, but
I have never had any problems other than oiling the blower motor and
changing the filter. I also filled in the gas nozzle and then drilled
it out with a smaller size drill so the gas flow is about half of what
it used to be, so it doesn't burn as hot and I put less heat up the
chimney. I have the blower temperature sensors set low so the blower
comes on at a low temperature and runs until the air is down to about
80F. That extracts most of the possible heat available. I have
provided a 6-inch diameter air inlet directly from the outside to feed
into the combustion area so it doesn't use heated household air, and I
have a carbon monixde detector close to the furnace as well as a
couple near the bedrooms in case the big can ever develops a leak. My
gas bill is way down from what is was when we first owned the house.
So newer is not always better.......