Air Conditioning - Heat Pump Fan Shuts Off - Outdoor Unit
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surypap3
06-09-08, 05:14 PM
Looking for some thoughts here. My heat pump operating in AC mode runs for about 10-15 minutes and then the fan cuts off. After shutting the unit off for a short period, and then restarting, the fan will come back to life, but then shuts down again in about 10-15 minutes. It demonstrates this behavior exactly on every trial. Thoughts?
Thanks
Jack
Thanks
Jack
pflor
06-10-08, 05:08 AM
Well...
The motor of the fan may be defective, or it may have a sensor that has gone bazook.
Some high end systems have on the outdoor unit side either a pressure or a temperature switch that cycles the fan ON-and-OFF as needed to prevent the outdoor pressure from getting too low.
Is it only the fan the one turning OFF (at first anyway), followed by the compressor also stopping? Or do both turn OFF at the same time? If BOTH are shutting themselves OFF at the same time, you may have an undercharge condition (lack of refrigerant)
Has this fan motor done that in the past or is it a recent occurrence? If it has never cycled prior to this season, then you likely have a motor that is going bad.
But to find out more info regarding the outdoor unit will be helpful. MFR and M/N.
The motor of the fan may be defective, or it may have a sensor that has gone bazook.
Some high end systems have on the outdoor unit side either a pressure or a temperature switch that cycles the fan ON-and-OFF as needed to prevent the outdoor pressure from getting too low.
Is it only the fan the one turning OFF (at first anyway), followed by the compressor also stopping? Or do both turn OFF at the same time? If BOTH are shutting themselves OFF at the same time, you may have an undercharge condition (lack of refrigerant)
Has this fan motor done that in the past or is it a recent occurrence? If it has never cycled prior to this season, then you likely have a motor that is going bad.
But to find out more info regarding the outdoor unit will be helpful. MFR and M/N.
surypap3
06-10-08, 01:06 PM
Thanks for your thoughts. I will get the Mftr info when I get home.
This is a unit that was freezing up during the winter. We replaced the defrost board, and then noticed the fan problem.
The fan was replaced next. However, there was no change in the symptoms. The new fan shut down in 10 mins or so.
I think the refrigerant has been checked as satisfactory, but I will need to ask my son who has been helping me. He is very young in his HVAC experience and has since left the business.
The fan shuts off before the compressor. And I don't know enough to let it stay in that situation so I shut down the unit at that point. The compressor is amping on the high end according to my son.
Shiould I leave the unit running to see if the fan comes back on? I had assumed that to be bad since my other uni's fan runs consistently, as far as I can tell.
Does this shed any light?
Jack
This is a unit that was freezing up during the winter. We replaced the defrost board, and then noticed the fan problem.
The fan was replaced next. However, there was no change in the symptoms. The new fan shut down in 10 mins or so.
I think the refrigerant has been checked as satisfactory, but I will need to ask my son who has been helping me. He is very young in his HVAC experience and has since left the business.
The fan shuts off before the compressor. And I don't know enough to let it stay in that situation so I shut down the unit at that point. The compressor is amping on the high end according to my son.
Shiould I leave the unit running to see if the fan comes back on? I had assumed that to be bad since my other uni's fan runs consistently, as far as I can tell.
Does this shed any light?
Jack
surypap3
06-10-08, 03:20 PM
Looks like International Comfort Performance Product Corp, Model #HHP048AKA1.
pflor
06-10-08, 07:09 PM
Your unit is a HEIL. This is one of the brands manufactured by International Comfort Products. They make many others.
I do not see any cycling switches in the schematic for your heat pump. The only fan switch I see is the one that connects to the defrost board.
Just to check if this switch is (or is not) the cause of the problem, run the following test:
There are "3" wires coming off the condenser fan motor. One of them is black and goes to a terminal on the defrost board. Next to it is a second terminal with another black wire that goes to terminal T2 on the contactor coil.
Put a jumper between these two black wires at the defrost board (they are next to each other and the word "fan" should be clearly labeled there, in between these two terminals).
If the fan no longer stops with the jumper in place, then there's some problem, possibly with the defrost board itself. If the problem subsists, then the fan motor is defective (it is likely overheating and the internal thermal overload is shutting it OFF as you have indicated)
1086397 is the part number for this condenser fan motor, should you decide to get it directly from them (assuming of course that the fan motor is bad)
1086646 is the part number for the dual capacitor (7.5+50mfd, 370V)
I do not see any cycling switches in the schematic for your heat pump. The only fan switch I see is the one that connects to the defrost board.
Just to check if this switch is (or is not) the cause of the problem, run the following test:
There are "3" wires coming off the condenser fan motor. One of them is black and goes to a terminal on the defrost board. Next to it is a second terminal with another black wire that goes to terminal T2 on the contactor coil.
Put a jumper between these two black wires at the defrost board (they are next to each other and the word "fan" should be clearly labeled there, in between these two terminals).
If the fan no longer stops with the jumper in place, then there's some problem, possibly with the defrost board itself. If the problem subsists, then the fan motor is defective (it is likely overheating and the internal thermal overload is shutting it OFF as you have indicated)
1086397 is the part number for this condenser fan motor, should you decide to get it directly from them (assuming of course that the fan motor is bad)
1086646 is the part number for the dual capacitor (7.5+50mfd, 370V)
Saturn
06-10-08, 07:15 PM
This is a unit that was freezing up during the winter. We replaced the defrost board, and then noticed the fan problem.
The fan was replaced next. However, there was no change in the symptoms. The new fan shut down in 10 mins or so.
They may have hooked the new board up incorrectly or it may simply be the wrong board I would start there and verify the baord compatibilty and then proper wiring before progressing any further> any previous work is supect especially if the problem started right after the work was done
The fan was replaced next. However, there was no change in the symptoms. The new fan shut down in 10 mins or so.
They may have hooked the new board up incorrectly or it may simply be the wrong board I would start there and verify the baord compatibilty and then proper wiring before progressing any further> any previous work is supect especially if the problem started right after the work was done