I’m having an issue with my furnace / nest thermostat that only occurs at night. During the day everything works fine. Starting at around 9PM, at the next call for heat, the furnace will fire (natural gas), then shut down with an error code 13. This locks it out, so we have no heat. It will eventually restart in the morning after about six plus hours. Sometimes when it restarts it will shutdown with error code 33, then run with fan only (no heat), then restart and work for the rest of the day. This is a six year old horizontal Carrier unit installed in the antic serving upper floor, model 59SP5A040E14. We have a similar unit and thermostat in the basement serving the first floor with no issues. We have had a tech look at the furnace and everything looks “perfect”. Clean condensate drain, fan speed high, gas pressure correct, combustion / flue gas excellent, flutes clean, flame sensor resistance correct, new air filter, all vents open. Again, it operates fine during the day. I did notice something funny in the nest history. During the day, The heat will go on for 15-20 minutes to reach setpoint. But at night, the nest is calling for heat for only a minute or two and then stopping. It then starts a call for heat a few minutes later and the furnace is not working, so the call for heat continues for the rest of the night. There are also a few periods during this time when the nest stops calling for heat. I’ll try to attached an image. Can’t figure out if it is an issue with the furnace or the nest. The furnace is getting errors that imply it is overheating, but we can’t find a cause. The only difference between night and day could be outside air temperature (colder at night), but that doesn’t seem to be a consistent factor. Why would the nest history show these strange heating patterns at night? There are no setpoint changes in the schedule. Any ideas would be appreciated!
Good evening,
I've been troubleshooting my Goodman furnace for a few days and it will not fire. Here's what I know:
1. I am receiving the three-flash code--meaning the pressure switch is not closing
2. I have cleared out the flue and even tested without the flue attached
3. The pressure switch is functional (if I create suction using mouth the switch does close and the furnace ignites)
4. The tubing is in good condition and clear of obstructions
5. The inducer motor fan is running correctly
6. I feel absolutely no vacuum from the inducer motor on the tubing connected to the collection chamber (first time working on this, so not sure if it would be a perceptible suction)
I'm fairly sure it has something to do with the inducer. I've cleaned the connection point with a needle and there is air blowing out into the flue, but the pressure switch is still not being triggered. I do not have the device to test suction. I even purchased a new pressure sensor that requires less suction and it still doesn't trigger. Does anyone have any idea what the issue may be? I've exhausted my current knowledge.
Thank you in advance!
By the way, I moved into this home this year so I have not run the furnace before
Here’s the gist. 1990’s Armstrong down draft furnace. Currently in garage shop. New flame sensor, new old style limit switch. (It has the copper jumper wire on it) The kind with the spring coil control. Turn on heat, flame comes on, fan then shortly after. But, the fan comes on before the switch hits the point where the fan should kick on. Then after heating up a bit it starts clicking allot and the flame keeps shutting down and coming back on. Over and over. Note: The air coming in in probably pretty cold. Someone told me that could be a factor. It’s just a garage furnace a bypass would work unless it’s dangerous. I’m wanting to put a timer control on it anyway.
11-26-21, 05:19 AM
