Payne/Carrier furnace kicks out early - http://www.hvacmechanic.com/ Forums
Original message
| Ranger
 |  "Payne/Carrier furnace kicks out early"
, posted Mon 10 Nov 11:24  
Hello,
My ten year old Payne/Carrier propane forced air furnace starts, burns for a few minutes, clicks several times, turns the gas off, restarts, clicks, turns gas off. After about three times of that it goes silent. If I turn the electric off/on, then it may start/click/off/restart/click/off ... or it may run fine for a few days. To try to isolate the problem I 'jumpered' around the fault cut out switches for: gas pressure, high heat, air pressure differential, (not flame). When I jumpered the air pressure differential switch it continued to run without early shut off. I ran the furnace several times with the air pressure differential switch jumpered to see if it was a faulty switch or if in deed there was an air pressure problem. On what turned out to be the last time I ran it in this mode (when watching through the little site glass) the flame in the number 2 burner moved back by the orifice in the manifold. At that point I thought that the main heat exchanger must be blocked by soot. (inlet and exhaust are clear and within specs, condensing heat exchanger was changed last year on warranty because of rot and leaks). I took the thing apart and the heat exchangers are clean as a whistle. What could it be ? The blades on the inducer fan have a thin stain on them but are fairly clean.
Thanks
Ranger
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Replies:
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| Xenos
Webmaster 
| "Re(1):Payne/Carrier furnace kicks out early" , posted Mon 10 Nov 18:22
From the way it sounds I would say its flame current. The clicking you are hearing sounds like to module sensing good current then loosing it. Clean off the flame rod with sand paper or a wire brush.
Xenos.
The best way to escape a problem is to solve it.
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| | ranger
| "Re(2):Payne/Carrier furnace kicks out early" , posted Mon 10 Nov 22:08
Hello Xenos,
Thank you for helping me. From reading the site it looks like you help a lot of people.
Your reply answers the question of why when I broke the pressure switch connection manually there was no click, but the gas did shut off immediately. I'm a little uncomfortable about seeing the flame move to the back of tube 2 while I was watching. By the way, before starting my test session yesterday I cleaned the condensate trap and reloaded system with water. Also, I checked the voltage passing through the air pressure switch, it was usually about 24v, but would drop to as low as 6v occassionally, but the gas didn't seem to shut off from a quick low bounce in voltage. Do you know why when the air switch was jumped the system operated up to temperature without shut off ? The flame rod looks pretty clean. I'm going to put it back together and try it.
Many Thanks,
Ranger
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| | Xenos
Webmaster
| "Re(3):Payne/Carrier furnace kicks out early" , posted Tue 11 Nov 18:09
This flame movement thing and the pressure switch make me think about a crack in the heat exchanger. When the fan starts do the flames move any?
Xenos.
The best way to escape a problem is to solve it.
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| | ranger
| "Re(4):Payne/Carrier furnace kicks out early" , posted Wed 12 Nov 17:27
I have the unit un-installed right now, I've removed it to the garage to work on it. I put the sealed pieces back on last night. Is there a relatively simple way to pressure test the exchangers ? I will inspect all, is exchanger 2 likely to be the culprite ? if there is one.
Thanks,
Ranger
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| | Xenos
Webmaster
| "Re(5):Payne/Carrier furnace kicks out early" , posted Wed 12 Nov 23:38
What’s the model number of the unit? I will pull up a diagram and see what exchanger it has.
Xenos.
The best way to escape a problem is to solve it.
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| | ranger
| "Re(6):Payne/Carrier furnace kicks out early" , posted Thu 13 Nov 12:23
Thanks for sticking with me. I did a careful visual inspection and there is no corrosion, cracks, or bad seams on either heat exchanger, the condensing was new last year. I ran the inducer fan stand alone with no pipes, it is much weaker than I expected, sounds fine.
Model: 398aav036080
Thanks,
Ranger
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| | Xenos
Webmaster
| "Re(7):Payne/Carrier furnace kicks out early" , posted Thu 13 Nov 18:24
I cant seam to get that comment about the flame coming back out of my head. My next step would be to check the furnaces consumption and make sure it’s funning at full capacity.
Look here http://www.hvacmechanic.com/howto.htm#where
Xenos.
The best way to escape a problem is to solve it.
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| | Xenos
Webmaster
| "Re(7):Payne/Carrier furnace kicks out early" , posted Thu 13 Nov 18:24
I cant seam to get that comment about the flame coming back out of my head. My next step would be to check the furnaces consumption and make sure it’s funning at full capacity.
Look here http://www.hvacmechanic.com/howto.htm#where
Xenos.
The best way to escape a problem is to solve it.
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| | ranger
| "Re(8):Payne/Carrier furnace kicks out early" , posted Fri 14 Nov 10:59
The unit is propane so I don't have a meter. At the point when there was flame in the little cup in front the orifice I had the pressure switch jumped and the furnace had been running about three minutes. The clicking sound was happening several times per minute but the flame did not go out. When I saw nice clean blue flame in the little cup area I panicked and turned the power off. The flame in the cup area was not violent, it was 'soft'. There is not any indication that flame has been in that area regularly, no discoloration.
Thanks,
Ranger
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| | Xenos
Webmaster
| "Re(9):Payne/Carrier furnace kicks out early" , posted Fri 14 Nov 18:11
You need to have the gas pressure verified. I would suggest you contact you propane distrubuter and ask for then to verify their regulators setting.
Xenos.
The best way to escape a problem is to solve it.
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