Furnace turns off prematurely
 

I have a Fridgidaire 90+AFUE furnace that, at times, will start and
stop prematurely. By this I mean that I hear the pilot light start,
then the gas turns on and starts burning, but then the gas shuts off
after 8 or 9 seconds, then finally the blower motor turns on for about
30-45 seconds. This occurs over and over but I have yet to determine
for how long. At first I thought my thermostat was failing (LUX brand)
so I replaced it with a Honeywell - same thing. Is this normal
behavior for a three year old furnace (this being the first winter that
I've noticed the "problem")? I will admit to having done no real
maintenance on this unit since I moved in so if it's a dirty/bad
sensor or something else that's failing then I have nobody to blame
but myself. If its not normal behavior what things can I try to
resolve the problem?

Furnace turns off prematurely
 

"new2059" wrote in message
ups.com...
I have a Fridgidaire 90+AFUE furnace that, at times, will start and
stop prematurely. By this I mean that I hear the pilot light start,
then the gas turns on and starts burning, but then the gas shuts off
after 8 or 9 seconds, then finally the blower motor turns on for about
30-45 seconds. This occurs over and over but I have yet to determine
for how long. At first I thought my thermostat was failing (LUX brand)
so I replaced it with a Honeywell - same thing. Is this normal
behavior for a three year old furnace (this being the first winter that
I've noticed the "problem")? I will admit to having done no real
maintenance on this unit since I moved in so if it's a dirty/bad
sensor or something else that's failing then I have nobody to blame
but myself. If its not normal behavior what things can I try to
resolve the problem?


I'd try calling a heating contractor. If you don't know a good one, ask a
few neighbors or friends.

Furnace turns off prematurely
 

Sounds like a limit switch needs adjustment; have a yearly
service done on it.


"new2059" wrote in message
ups.com...
:I have a Fridgidaire 90+AFUE furnace that, at times, will start
and
: stop prematurely. By this I mean that I hear the pilot light
start,
: then the gas turns on and starts burning, but then the gas
shuts off
: after 8 or 9 seconds, then finally the blower motor turns on
for about
: 30-45 seconds. This occurs over and over but I have yet to
determine
: for how long. At first I thought my thermostat was failing
(LUX brand)
: so I replaced it with a Honeywell - same thing. Is this normal
: behavior for a three year old furnace (this being the first
winter that
: I've noticed the "problem")? I will admit to having done no
real
: maintenance on this unit since I moved in so if it's a
dirty/bad
: sensor or something else that's failing then I have nobody to
blame
: but myself. If its not normal behavior what things can I try
to
: resolve the problem?
:

Furnace turns off prematurely
 

There's a sensor that either needs repair or replacing. For a skilled
technician, it shouldn't take very long. Call a local HVAC contractor. Tell
them you would also like a heater checkup.

"new2059" wrote in message
ups.com...
I have a Fridgidaire 90+AFUE furnace that, at times, will start and
stop prematurely. By this I mean that I hear the pilot light start,
then the gas turns on and starts burning, but then the gas shuts off
after 8 or 9 seconds, then finally the blower motor turns on for about
30-45 seconds. This occurs over and over but I have yet to determine
for how long. At first I thought my thermostat was failing (LUX brand)
so I replaced it with a Honeywell - same thing. Is this normal
behavior for a three year old furnace (this being the first winter that
I've noticed the "problem")? I will admit to having done no real
maintenance on this unit since I moved in so if it's a dirty/bad
sensor or something else that's failing then I have nobody to blame
but myself. If its not normal behavior what things can I try to
resolve the problem?

Furnace turns off prematurely
 

Thanks all for the input. I'm assuming you're referring to the
heat/flame sensor - is this correct? If so, is anyone familiar with
this Frigidaire model and the location of the sensor? I've read
elsewhere that using a small steel brush to clean it might do the
trick. Is this something that you would recommend doing on a
monthly/yearly/seasonal basis?

Furnace turns off prematurely
 

first thing. have you checked your air filter? i had a electronic air
cleaner that would cause the same exact thing when it got too dirty.
"Doug Kanter" wrote in message
...

"new2059" wrote in message
ups.com...
I have a Fridgidaire 90+AFUE furnace that, at times, will start and
stop prematurely. By this I mean that I hear the pilot light start,
then the gas turns on and starts burning, but then the gas shuts off
after 8 or 9 seconds, then finally the blower motor turns on for about
30-45 seconds. This occurs over and over but I have yet to determine
for how long. At first I thought my thermostat was failing (LUX brand)
so I replaced it with a Honeywell - same thing. Is this normal
behavior for a three year old furnace (this being the first winter that
I've noticed the "problem")? I will admit to having done no real
maintenance on this unit since I moved in so if it's a dirty/bad
sensor or something else that's failing then I have nobody to blame
but myself. If its not normal behavior what things can I try to
resolve the problem?


I'd try calling a heating contractor. If you don't know a good one, ask a
few neighbors or friends.

Furnace turns off prematurely
 

look up your make and model and find the manual online at the
manufacturer's website.
search for spark ignitor or glow ignitor at www.grainger.com to see
what they look like.
gas furnaces for beginners require a checkup every two years [oil ones
get an annual checkup].

Furnace turns off prematurely
 

A hot surface ignitor should not be cleaned, you will crack it, then
you will need a new one. If it is spark ignited, well I never found a
need to clean those either. Sounds like low air flow caused by:
1) Restrictive air filter.
2) Restrictive or undersized duct system.
3) Registers turned of in parts of your house you are not using.
4) Blower speed set too low.

Other possibilities: Limit switch improperly set, heat anticipator on
thermostat improperly set.

Stretch

Furnace turns off prematurely
 

"Stretch" wrote in message
ups.com...
A hot surface ignitor should not be cleaned, you will crack it, then
you will need a new one. If it is spark ignited, well I never found a
need to clean those either. Sounds like low air flow caused by:
1) Restrictive air filter.
2) Restrictive or undersized duct system.
3) Registers turned of in parts of your house you are not using.
4) Blower speed set too low.

Other possibilities: Limit switch improperly set, heat anticipator on
thermostat improperly set.

Stretch


Here's a weird reason. I have a Goodman HE unit. It was behaving in an odd
way, too. Making its initial startup noises, then stopping without actually
going to the preheat step. I'd just moved into the house, so I stood in the
cellar listening to the noises so I could describe them to the heating guy
when I called. Standing right under the PVC vent pipe, I heard water
gurgling. Whoever installed the furnace did a lousy job of installing the
pipe hangers, so the vent was bowed downward almost an inch in the middle of
its run to the outside, so water was collecting there. I propped it up, the
water drained out, and the next time the heater started, it ran correctly. I
still had my contractor come over to check the machine over. He said this
heater checks for proper venting before turning on the gas, and that there
must've been enough water in the pipe to cause a problem.

Furnace turns off prematurely
 

That's not an uncommon problem, especially in housing developments.

"Doug Kanter" wrote in message
...

"Stretch" wrote in message
ups.com...
A hot surface ignitor should not be cleaned, you will crack it, then
you will need a new one. If it is spark ignited, well I never found a
need to clean those either. Sounds like low air flow caused by:
1) Restrictive air filter.
2) Restrictive or undersized duct system.
3) Registers turned of in parts of your house you are not using.
4) Blower speed set too low.

Other possibilities: Limit switch improperly set, heat anticipator on
thermostat improperly set.

Stretch


Here's a weird reason. I have a Goodman HE unit. It was behaving in an odd
way, too. Making its initial startup noises, then stopping without
actually
going to the preheat step. I'd just moved into the house, so I stood in
the
cellar listening to the noises so I could describe them to the heating guy
when I called. Standing right under the PVC vent pipe, I heard water
gurgling. Whoever installed the furnace did a lousy job of installing the
pipe hangers, so the vent was bowed downward almost an inch in the middle
of
its run to the outside, so water was collecting there. I propped it up,
the
water drained out, and the next time the heater started, it ran correctly.
I
still had my contractor come over to check the machine over. He said this
heater checks for proper venting before turning on the gas, and that there
must've been enough water in the pipe to cause a problem.