HP Compressor cycling before reaching set point

[600SL]

First day I have really cool 35° outdoor temperatures to run my new heat pump. I turned it on with an indoor temp of 51°. The temp got up to about 62° and the compressor turned off for about 30 sec. About 5 min later it turned off again and then back on in about 30 sec. So far 10 min later it has not turned off again. This system has not had its final charge checked because its too cold out. Could this be causing that. Or is it normal. If its low on 410 should I e concerned about running the system at all.

Set point is set at 68°

 

[tomroblee]

Defrost cycles?

 

[Brian_WK]

I was going to say defrost cycle when I first started reading but this doesn't sound like that.
Sounds like it is going off on a safety of some sort. If it is still off and calling for heat you can pull the control panel cover off of the HP outdoor unit and check the trouble code. It should be a blinking LED light the codes should be listed on the panel you removed.

Brian

 

[600SL]

I was going to say defrost cycle when I first started reading but this doesn't sound like that.
Sounds like it is going off on a safety of some sort. If it is still off and calling for heat you can pull the control panel cover off of the HP outdoor unit and check the trouble code. It should be a blinking LED light the codes should be listed on the panel you removed.

Brian

Does it have to be calling for heat, or does it store them. That would only give me a 30 second window of opportunity to get the cover off and look. I did just take the cover off and found the circuit board but I could not see any LED's at all. If it has them they are definitely not on or blinking.

All seams normal except it shut off 2 times for about 30 sec during its time bring the shop up to temperature, which took about 1 hour. There may have been 1 or 2 off cycles that I missed.

 

[Brian_WK]

So it was able to bring the shop up to temp without using the resistive heat?
I'm not completely up to date on how goodmans do their defrost cycle some manufactures use a quiet shift and some it sounds like air rushing out of a air tank. Defrost is determined in a few different ways depending on manufacturer. Some use refrigerant pressure, thermistors, time, air switches etc same for terminating the defrost cycle you will have to check your book. During a defrost cycle the compressor and indoor fan will run but the outdoor fan will shut off and the refrigeration cycle will reverse (run in air conditioning mode) during this time depending on how it is programmed it will also bring on the electric heat. Once the outdoor coil is thawed out the unit switches back to heat mode. There are some exceptions to this one is that some units once the unit goes into a defrost it will finish the heating cycle on backup heat source (gas or resistive) another is that after the unit has ran for X amount of time in heat pump it will automatically bring on your secondary source of heat to finish the cycle.

If it has LED's they would be stored (in my experience) Especially if it is a low or high pressure switch open or failed defrost of sorts. Can't say for sure what yours has check your book.

Brian

 

[600SL]

So it was able to bring the shop up to temp without using the resistive heat?
I'm not completely up to date on how goodmans do their defrost cycle some manufactures use a quiet shift and some it sounds like air rushing out of a air tank. Defrost is determined in a few different ways depending on manufacturer. Some use refrigerant pressure, thermistors, time, air switches etc same for terminating the defrost cycle you will have to check your book. During a defrost cycle the compressor and indoor fan will run but the outdoor fan will shut off and the refrigeration cycle will reverse (run in air conditioning mode) during this time depending on how it is programmed it will also bring on the electric heat. Once the outdoor coil is thawed out the unit switches back to heat mode. There are some exceptions to this one is that some units once the unit goes into a defrost it will finish the heating cycle on backup heat source (gas or resistive) another is that after the unit has ran for X amount of time in heat pump it will automatically bring on your secondary source of heat to finish the cycle.

If it has LED's they would be stored (in my experience) Especially if it is a low or high pressure switch open or failed defrost of sorts. Can't say for sure what yours has check your book.

Brian

Yes I was definitely able to bring it up to temp. On my unit the electric heaters come on when the temp is 1.6° below setpoint. That's adjustable to 4° actually 2 times the swing temp.

Both times I heard it shut down it sounded like air rushing out of an air tank, which is how I knew it happened. Unfortunately none of this is in the book that came with it. I will have to go online and see if I can find a more detailed service manual. Its sounding like all is operating according to design.

 

[Ohmthis]

Was it raining or 'wet' outside? That whoosh sound it the refrigerant escaping past the reversing valve during a defrost cycle. The humidity can make the coil frost quicker, so can a low charge or low air flow. Since the outside coil is the evaporator coil in heat mode a low charge can cause it to frost up. How long it your lineset? There are ways to charge a heat pump in the heat cycle. One is to weigh in the charge, the other is charging by discharge temp.use a thermometer to read the ambient air temp. Save this number and add it to 110. You would put a temp gauge (a meat thermometer does a good job if you don't have a meter to read temp) on the compressor discharge pipe. The ambient + 110 should equal the discharge temp. If the discharge temp is lower than your ambient + 110 it is over charged. If it is higher it is under charged. You will have to creep up to the temp with this method, but it does get you very close.

 

[600SL]

Was it raining or 'wet' outside? That whoosh sound it the refrigerant escaping past the reversing valve during a defrost cycle. The humidity can make the coil frost quicker, so can a low charge or low air flow. Since the outside coil is the evaporator coil in heat mode a low charge can cause it to frost up. How long it your lineset? There are ways to charge a heat pump in the heat cycle. One is to weigh in the charge, the other is charging by discharge temp.use a thermometer to read the ambient air temp. Save this number and add it to 110. You would put a temp gauge (a meat thermometer does a good job if you don't have a meter to read temp) on the compressor discharge pipe. The ambient + 110 should equal the discharge temp. If the discharge temp is lower than your ambient + 110 it is over charged. If it is higher it is under charged. You will have to creep up to the temp with this method, but it does get you very close.

Sound like I may be low on charge since I did have to up size the line to go over 25'. My total line length is about 35' up sized from 7/8" to 1 1/8". No 410 was added at this time. But it does work well for the moment is there any risk of waiting until spring to do a final charge.

The day before it had been raining.