Goodman Heat Pump Air Handler Fan Isn't Coming On
#1
08-18-09, 04:12 PM
Goodman Heat Pump Air Handler Fan Isn't Coming On
I have a Goodman Heat Pump that is approximately 8 years old. When it was less then a year old, the air handler's (Model AR36-1) blower motor failed and was replaced under warranty. At the time the installer told me there was a bad lot of motors and he had recently replaced quite a few of them that had failed while they were new. Ever since then, the system has performed flawlessly. 
Last week (i.e. 7 years later), I was hot. I went to the T-Stat (Honeywell programmable) to discover it was calling for cool but the room temp was high. The outside condenser unit was running, but the blower within the air handler was not on. I went down to the handler, shut off the power, and opened it up. The coils were icy.
Looking for the obvious things first, I looked at the motor run capacitor. It looked ok at first glance but upon closer inspection I saw it was covered in sticky gel. I assumed it was leaking and had failed. I replaced the cap, powered up, turned on the T-Stat and the AC came right on. Problem solved, or so it seemed.
After a week of seemingly working fine, I again am hot and go to the T-Stat. Again the T-Stat is calling for cool but the temp is high and the fan is not running. Where the coolant line enters the air handler, there is ice, so I assume we have ice on the coils again.
I shut off the T-Stat, waited a few minutes, and then put the fan to ON (instead of AUTO). I left the compressor off. Surprisingly, the fan started right up. I let it run a while to melt the ice off the coils, and then turned on the compressor (switched T-Stat to COOL). Since the fan was already running, the AC started cooling my house.
I am fairly certain that the cap I replaced was bad due to the gel leaking out, so I am not too worried about spending the $6 on the replacement. But now I suspect that the cap may have been a red herring. Perhaps it was indeed failing/leaking but still working, and the problem actually lies elsewhere.
When the blower motor is running, it seems normal (no bearing noise, unusual humming, smells, noises, etc). I think this is a control problem. My candidates are (1) T-Stat (2) A loose connection (3) relay sequencer (4) bad motor (5) something else. I have checked all the wire nuts on the control conductors (where the cables all meet at the air handler) I am still going to do some tests to further clarify the symptoms. Why would the fan start on ON but not AUTO? Is that a repeatable behavior or does the fan merely successfully start randomly? That is one thing I will try to discover. If the fan ALWAYS starts reliably on ON but not AUTO, then I would tend to suspect the thermostat. But if it is more random, then it would seem to be the sequencer, loose wiring, or the motor itself. Any ideas would be appreciated. There are other posts describing this exact issue with a Goodman air handler, but the final diagnosis and solution was not shared.
Last week (i.e. 7 years later), I was hot. I went to the T-Stat (Honeywell programmable) to discover it was calling for cool but the room temp was high. The outside condenser unit was running, but the blower within the air handler was not on. I went down to the handler, shut off the power, and opened it up. The coils were icy.
Looking for the obvious things first, I looked at the motor run capacitor. It looked ok at first glance but upon closer inspection I saw it was covered in sticky gel. I assumed it was leaking and had failed. I replaced the cap, powered up, turned on the T-Stat and the AC came right on. Problem solved, or so it seemed.
After a week of seemingly working fine, I again am hot and go to the T-Stat. Again the T-Stat is calling for cool but the temp is high and the fan is not running. Where the coolant line enters the air handler, there is ice, so I assume we have ice on the coils again.
I shut off the T-Stat, waited a few minutes, and then put the fan to ON (instead of AUTO). I left the compressor off. Surprisingly, the fan started right up. I let it run a while to melt the ice off the coils, and then turned on the compressor (switched T-Stat to COOL). Since the fan was already running, the AC started cooling my house. I am fairly certain that the cap I replaced was bad due to the gel leaking out, so I am not too worried about spending the $6 on the replacement. But now I suspect that the cap may have been a red herring. Perhaps it was indeed failing/leaking but still working, and the problem actually lies elsewhere.
When the blower motor is running, it seems normal (no bearing noise, unusual humming, smells, noises, etc). I think this is a control problem. My candidates are (1) T-Stat (2) A loose connection (3) relay sequencer (4) bad motor (5) something else. I have checked all the wire nuts on the control conductors (where the cables all meet at the air handler) I am still going to do some tests to further clarify the symptoms. Why would the fan start on ON but not AUTO? Is that a repeatable behavior or does the fan merely successfully start randomly? That is one thing I will try to discover. If the fan ALWAYS starts reliably on ON but not AUTO, then I would tend to suspect the thermostat. But if it is more random, then it would seem to be the sequencer, loose wiring, or the motor itself. Any ideas would be appreciated. There are other posts describing this exact issue with a Goodman air handler, but the final diagnosis and solution was not shared.
#2
08-18-09, 04:21 PM
Update
Again I come home to a hot house, with the TStat calling for cool. I switched the fan from AUTO to ON, and nothing. Then, I turned the AC from COOL to OFF. Immediately the fan comes on. Then I can turn the thermostat back to COOL and the AC starts cooling the house. Weird, huh?
I am going to try to repeat this sequence every time the fan fails to come on to see if the behavior is consistent. I am thinking the motor is fine and this is a problem with the TStat or the sequencer relay. It appears my flipping the buttons on the TStat causes the problem to temporarily resolve.
I dislike my particular programmable Honewell TStat (it only has a 30 min power backup in the event the power goes out... lame). I think it must be the absolute cheapest model Honeywell ever made. So I am thinking about replacing it with a nicer one and in the process eliminating the TStat possibility.
Any ideas appreciated.
I am going to try to repeat this sequence every time the fan fails to come on to see if the behavior is consistent. I am thinking the motor is fine and this is a problem with the TStat or the sequencer relay. It appears my flipping the buttons on the TStat causes the problem to temporarily resolve.
I dislike my particular programmable Honewell TStat (it only has a 30 min power backup in the event the power goes out... lame). I think it must be the absolute cheapest model Honeywell ever made. So I am thinking about replacing it with a nicer one and in the process eliminating the TStat possibility.
Any ideas appreciated.
#3
08-21-09, 12:05 PM
The fan has more then one speed. More then likely high - med - low.
In heating fan runs on low speed(hot air is lighter) high speed for cooling you guessed it cold air heavier.
More then likely lost the high speed winding on the motor putting the fan switch to on may be differant winding. Motor will run then heat up and trip on thermal overload.
If you have a meter and know how to use it you can verify my highly educated guess......just kidding.
Thats where I would start
In heating fan runs on low speed(hot air is lighter) high speed for cooling you guessed it cold air heavier.
More then likely lost the high speed winding on the motor putting the fan switch to on may be differant winding. Motor will run then heat up and trip on thermal overload.
If you have a meter and know how to use it you can verify my highly educated guess......just kidding.
Thats where I would start
#4
08-24-09, 09:00 AM
Member
Join Date: Aug 2009
Location: Alabama
Posts: 1
Upvotes: 0
Received 0 Upvotes
on
0 Posts
I am having the same problem with my Goodman air handler. Fan not coming on, coils icing up and I can cycle the cool switch to off and back on to clear the problem temporarily. I too replaced my capacitor. My model is number is A-42-15. I had a service company come out and check the system but since it wouldn't malfunction at the time, they couldn't find a problem. I haven't taken any voltage readings yet but I will if I can catch it at the right time.
#6
08-31-09, 05:05 PM
update 31Aug09
Hello all...
I have been out of town until yesterday but my heat pump is still acting up. I am not certain that my fan has two speeds, but I suppose it is certainly possible. The fan doesn't sound any different to me between heating (in winter) and AC (in summer).
I will open the handler up again and take a good look at the wires running to the motor. I will post a pic if I can.
My fan wasn't on today, and I switched it to ON... nothing. Then I turned the AC from COOL to OFF and the fan came on within seconds! Then I go back to cool and my AC resumes it's normal operation. Very odd.
If matthew is like me, he replaced the run capacitor which is strapped to the blower motor inside the air handler. As indicated in my first post, mine was leaking gel.
I have been out of town until yesterday but my heat pump is still acting up. I am not certain that my fan has two speeds, but I suppose it is certainly possible. The fan doesn't sound any different to me between heating (in winter) and AC (in summer).
I will open the handler up again and take a good look at the wires running to the motor. I will post a pic if I can.
My fan wasn't on today, and I switched it to ON... nothing. Then I turned the AC from COOL to OFF and the fan came on within seconds! Then I go back to cool and my AC resumes it's normal operation. Very odd.
If matthew is like me, he replaced the run capacitor which is strapped to the blower motor inside the air handler. As indicated in my first post, mine was leaking gel.
