A/C Fan stops after cooling but compressor still on till it overheats?
#1
09-10-18, 09:52 PM
A/C Fan stops after cooling but compressor still on till it overheats?
Any help/suggestions are greatly appreciated!
I've tested capacitor and it seems to be fine and motor spins also. Both work from a cold start after not being used for a while and cold air is flowing, but what's happening is that after a while of operating and cooling the fan stops but the compressor is still humming irregularly and gives off A LOT of hot air (it seems to occur moreso when it reaches/its about to reach the set desired temperature). If it's a problem with the compressor why is the fan turning off and stopping well before the compressor does (I'm assuming compressor overheats and protection is turning it off.... If there is such a function)? Thoughts?
I've tested capacitor and it seems to be fine and motor spins also. Both work from a cold start after not being used for a while and cold air is flowing, but what's happening is that after a while of operating and cooling the fan stops but the compressor is still humming irregularly and gives off A LOT of hot air (it seems to occur moreso when it reaches/its about to reach the set desired temperature). If it's a problem with the compressor why is the fan turning off and stopping well before the compressor does (I'm assuming compressor overheats and protection is turning it off.... If there is such a function)? Thoughts?
#2
09-10-18, 10:23 PM
Update: I just tested it again about 10 minutes after the problem happened again and this time it hesitated to turn the fan initially (sounded like capacitor was trying but fan had resistance), then the fan "grabbed" ( for lack of a better word) and suddenly it started spinning like normal, until about 10 seconds later it started making irregular frictional sounds and then halted. I think this is the fan motor then, yea?
The only other possibility I can think of is that the capacitor is responsible, but I'm not sure how the capacitor functions to be honest. it's my understanding that the first large number (55 microFarats) is the first large discharge to get the fan spinning from a dead-stop, and that the second small number is for prolonged continual spinning... Is this correct? Or once the fan motor takes over the capacitor's job is done (kind of like a car starter and car engine)? If the latter is true maybe the capacitor can't continuously discharge to keep the fan motor going?
Again any help is much appreciated!
The only other possibility I can think of is that the capacitor is responsible, but I'm not sure how the capacitor functions to be honest. it's my understanding that the first large number (55 microFarats) is the first large discharge to get the fan spinning from a dead-stop, and that the second small number is for prolonged continual spinning... Is this correct? Or once the fan motor takes over the capacitor's job is done (kind of like a car starter and car engine)? If the latter is true maybe the capacitor can't continuously discharge to keep the fan motor going?
Again any help is much appreciated!
#3
09-10-18, 10:40 PM
Group Moderator
If the capacitor has three terminals on it...... it's a dual cap. The larger number pertains to the H terminal which is for the compressor. The smaller value pertains to the F terminal which is for the fan.
If you checked the cap and it checks ok...... the fan motor has worn bearings and needs to be replaced.
Allowing the compressor to cycle on high heat will damage it.
If you checked the cap and it checks ok...... the fan motor has worn bearings and needs to be replaced.
Allowing the compressor to cycle on high heat will damage it.
#4
09-11-18, 03:02 AM
Super Moderator
It is likely the fan bearings.
You can check by moving the shaft on the fan motor from side to side to see if you can detect any movement.
The movement will be subtle and is more easily done if you remove the fan blade.
Don't be rough on the fan blade or you could put it out of balance.
You can check by moving the shaft on the fan motor from side to side to see if you can detect any movement.
The movement will be subtle and is more easily done if you remove the fan blade.
Don't be rough on the fan blade or you could put it out of balance.
#5
09-11-18, 07:05 AM
"You can check by moving the shaft on the fan motor from side to side to see if you can detect any movement.
The movement will be subtle and is more easily done if you remove the fan blade."
Can you elaborate please? I'm confused by the statement because if I'm manually moving the shafts side to side won't it be moving due to myself moving it? Or do you mean move the shafts and see if the bearings are transmitting the motion to the fan? Again, the fan is moving but it seems that once it heats up it stops.
The movement will be subtle and is more easily done if you remove the fan blade."
Can you elaborate please? I'm confused by the statement because if I'm manually moving the shafts side to side won't it be moving due to myself moving it? Or do you mean move the shafts and see if the bearings are transmitting the motion to the fan? Again, the fan is moving but it seems that once it heats up it stops.
#6
09-11-18, 07:11 AM
I think they're referring to "play", or wiggle in the shaft. If the bearings are good, there should not be much play in the shaft, nor any grinding.
I am no expert, but perhaps when the bearings heat up, they are causing friction and begin to drag on the races, stopping the fan?
I am no expert, but perhaps when the bearings heat up, they are causing friction and begin to drag on the races, stopping the fan?
#7
09-11-18, 09:30 AM
Super Moderator
There should be zero side to side play on the motor shaft.
A few thousands of an inch is too much and if you can feel it it's game over for the motor and will cause your symptoms.
Plus, you need to stop using your ac because much more and you will damage the compressor.
A few thousands of an inch is too much and if you can feel it it's game over for the motor and will cause your symptoms.
Plus, you need to stop using your ac because much more and you will damage the compressor.
#8
09-12-18, 08:56 AM
Have a similar issue on the FAN motor, but the FAN is certainly not stopping.
Tech identified that the shaft is loose, leaking oil and causing vibration. He also said that it will likely run fine for few years, but it's better replaced.
Personally, I would replace the FAN motor and the Capacitor.
Tech identified that the shaft is loose, leaking oil and causing vibration. He also said that it will likely run fine for few years, but it's better replaced.
Personally, I would replace the FAN motor and the Capacitor.
