Uh Oh... heat pump freezing up!?

[pancho400cid]

Hey all:

I have a Payne heat pump, model PH12NA024-A.

I noticed it "sounded funny". Took a look at the outside unit and see that it is freezing up?
it's working... the temp inside the house and the discharge temp seems fine.

This is a bit of an issue because we are heading for record cold temps. It's about 25 F now but headed for single digits tomorrow AM, with sleet/snow highly likely. I've lived in TX all my 57 years and don't recall ever seeing it that cold (single digits not including wind-chill).

Is it just freezing because it's cold? Low freon? Should I call a repairman?

I'm about to string a cord and melt the ice with my Porter Cable heat gun, but would appreciate any input.

Thanks!

 

[Texsun]

https://www.callaqm.com/blog/heat-pump-winter-ice/

 

[KenC]

Hey all:

I have a Payne heat pump, model PH12NA024-A.

I noticed it "sounded funny". Took a look at the outside unit and see that it is freezing up?
it's working... the temp inside the house and the discharge temp seems fine.

This is a bit of an issue because we are heading for record cold temps. It's about 25 F now but headed for single digits tomorrow AM, with sleet/snow highly likely. I've lived in TX all my 57 years and don't recall ever seeing it that cold (single digits not including wind-chill).

Is it just freezing because it's cold? Low freon? Should I call a repairman?

I'm about to string a cord and melt the ice with my Porter Cable heat gun, but would appreciate any input.

Thanks!

Nature of the beast. In some conditions it will freeze, then go into a defrost cycle when you will see clouds of steam and see a pool of water form.

If it fails to do that, then call for service.

 

[Hobby_Man22]

Must not be going into defrost mode.

 

[pancho400cid]

Thanks for the info and links. I defrosted it with a heat gun, but will keep an eye on it. Not sure if it's going into defrost mode or not, but will check that too.

 

[Jeepster04]

Depending on how long the defrost cycle is set to, that could be a normal amount of frost.

Let it got for a couple of days and see if it keeps building up. If it does, then its not defrosting and you have an issue. Ive seen them become a complete block of ice.

 

[crazy wheel]

Frost even heavier frost than what you have is normal.

 

[Bills Tools]

A heat pump is suppose to freeze. It should go into defrost mode to melt the ice off every now and then


Sent from my iPad using Garage Journal

 

[pancho400cid]

Thanks all. Been busy fighting the big storm. The frost issue became moot when we lost power. Got power back about 2 am after 48 hours. Went to check stuff about 8 am. Heard the outside unit humming before I rounded the corner. Ice had locked the fan up. Turned it off. Chipped away the ice and fired it back up. She's been running fine since. Who knew setting the outside unit under the drip line of the roof was a bad idea!!??.

Appreciate the info!

Temps should be consistently above freezing starting Saturday. Now... if the water will come back on, all I'll need to worry about is boiling it.

 

[dutchgray]

Easy way to defrost them if you don't want to wait for the defrost cycle, aim a space heater at it for while.

 

[Hobby_Man22]

Are they supposed to defrost after running a certain amount of time.

 

[Milton Shaw]

Easiest way to defrost is to turn it to air conditioning for 15 minutes or so and wall the ice will melt quickly. That amount is normal though and will defrost off the next cycle. Some cycle on time (90 minutes or so) and some on temp of unit. The exact opposite is the way do defrost the inside coil in air conditioner mode if it freezes up. The normal operation in defrost is fan turns off, reversing valve changes state and then the ice melts until a thermostat on coil reaches 40 or so degrees and then reversing valve changes again and fan comes back on and blow out a cloud of steam, then it goes back to heating.

 

[dutchgray]

Easy way to defrost them if you don't want to wait for the defrost cycle, aim a space heater at it for while.

This,
Sometimes you need as much heat as you can get out of them in really cold weather and waiting on the defrost cycle is a no go.

 

[bonneyman]

I'm not 100% sure of the type of defrost on your model but it's probably a time/temp board or a demand (only defrosts when the computer determines it needs to) control. The time/temp boards typically have a temp sensor on the last leg of the outdoor coil that closes around 25-28 deg. The timer in the board runs all the time, checking every 30, 60, or 90 minutes (whatever setting is chosen - typically 90 minutes). If the timer reaches a check time - and the temp sensor - the unit goes into defrost. Either until the refrigerant temp coming out of the coil hits a temp that the designers figure means the ice is gone (say 65 deg) or after 10 minutes of defrost (forced override). Any one of a number of malfunctions and ice will slowly build up on the coil, and no real heat comes out of it.
Such as;
High humidity (if air temperature is above 32 deg) will make the coil ice more and faster than the control can handle. Reset timer function to shorter time setting may help.
Temp sensor fails to close, or is loose (not properly sensing the existing temperature), or is out of calibration.
Board connections have cold solder joints and not picking up sensor signal, or outdoor fan doesn't go off during defrost, or it terminates defrost cycle prematurely. Or board could just be bad - won't affect cooling at all but heating will screw up.

Whenever I had a icing coil I removed the temp sensor and replaced it, cleaning the contact point in the process and covering it with cork tape. Sensor was $40 plus time - no biggie. But recent defrost boards have the sensor hard soldered to the board, so you gotta replace the whole thing. This not be cheap! I used to check board function but had several pass my test and then still not work right.

Hope this helps!