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chillingout · Jan 5, 2009, 07:38 PM

The glow plug comes on nice and bright, the jets fire full flames which lasts all about 10 sec's before I hear and "CLICK" and the gas shuts off. The glow plug which was going dim just before the gas kicked off is now red hot again waiting for the second try to fire. Second try the flame stays on even shorter. Now the blower motor kicks on, third attempt fail. Now I have to shut down the system and restart.

My best guess:

The system fired theirfore its not a mechanical issue. I assume its on of the following:

Gas Regulator
Temp Sensor
High limit

Ps... I am not sure if this matters to this specific issue however during extreme heat 90+ the AC freezes, in extreme cold below 40 degrees I have been having issues keeping the house at a high temp. In the past it would keep the house warm ( low 60's ) if the outside temp was below 35 ish.

greghvacguy · Jan 5, 2009, 07:46 PM

Sounds like the flame sensor needs to be cleaned. It on the left side.(other side from his the thing glowing red) Its in front of the buner clean it with sand papper the wire brush.
For the ac iceing up can be from low freon,dirty filter or coil. If filter is dirty or coil you may not be getting the right air flow and furnace sutting down on limit.
First clean the flame sensor it get furnace running and see if it runs till thermostat make the temp. it should stay on till it gets to temp. if not look at board in blower and count the flashes and let us know

MarkwithaK · Jan 5, 2009, 07:53 PM

Ditto on the FS. When hvac1000 comes along he has a pick of it that should help.

greghvacguy · Jan 5, 2009, 08:12 PM

HVAC 1000 where are you

MarkwithaK · Jan 5, 2009, 08:19 PM

Probably counting his nickels.

hvac1000 · Jan 5, 2009, 11:45 PM

Originally Posted by chillingout

The glow plug comes on nice and bright, the jets fire full flames which lasts all about 10 sec's before I hear and "CLICK" and the gas shuts off. The glow plug which was going dim just before the gas kicked off is now red hot again waiting for the second try to fire. Second try the flame stays on even shorter. Now the blower motor kicks on, third attempt fail. Now I have to shut down the system and restart.

My best guess:

The system fired theirfore its not a mechanical issue. I assume its on of the following:

Gas Regulator
Temp Sensor
High limit

Ps.... I am not sure if this matters to this specific issue however during extreme heat 90+ the AC freezes, in extreme cold below 40 degrees I have been having issues keeping the house at a high temp. In the past it would keep the house warm ( low 60's ) if the outside temp was below 35 ish.

Flame sensor cleaning pic. Yours might not look exactly like this one but they do the same thing.

chillingout · Jan 6, 2009, 09:35 AM

Thank you Gentleman. So here's an update...

It would seem for the moment that the short cycling was due to air flow restriction.. IE dirty filter. I take the filter out, the system ran fine all day. But did eventually shut off sometime at night. I have been trying to restart the system with no luck. I shake the dirty filter off (Purple 3M allergyn 100% filter) and presto it works. I went to home depot to purchase 70% air flow filters which should work.

I have a professional coming in for $70 is dollars to give me a quick review clean up of the system. Its 15 years old. Well done on the picture post of the heat sensor. I looked all over Google last night and couldn't find a pick as I was taking your advise to find it and scrub it clean.

Wouldn't it be ironic if the AC was freezing due to a dirty filter, the cold air backing up and freezing the coil. I guess its possible but I will find out in the spring.

As for now, the house is back up to temp, thank you much!

hvac1000 · Jan 6, 2009, 12:49 PM

Hope it keeps running.

chillingout · Jan 6, 2009, 01:47 PM

Originally Posted by hvac1000

Hope it keeps running.

If not, you guys will be the first to know.

:-)

hvac1000 · Jan 6, 2009, 02:14 PM

Nothing that we like more than repete customers. LOL