Thread: Heat pump freeze-up

Louisiana home: 7-yrs. old with (International Comfort Products) heat pump and electric heat furnace in attic. I performed my inspection and visually saw a 3-4 in. band of ice on the exterior of the heat pump approximately 12-in. from the base of the unit. The temperature was 58-59 degrees and was raining at the time of inspection. I turned on the heat inside to 75 degrees and the supply registers were at 110-111 degrees, with the emergency heat on the supplys went to 133. Returns were at 70 degrees. I shut the system off so pressures could equilize and turned on the air after approx. 15-20 minutes. The supply registers were at 55-56 returns at 69-70. I did not see a problem with the system operation as I have read that heat pumps will freeze up in high humidity/rainy weather. Here's the problem: Inspection was performed on Jan. 16, 2008 and new owners moved in on the 21st of Jan., (3) days later the complete unit froze up and would not heat the home. Owner called tech and filled with freon. (2) days later the unit froze up again. Tech says they need complete new unit. They are now coming to me. I told them it was working on the day of the inspection and owners wife and son were there when I performed my systems operation and temp. checks.
"How about some input from the A/C guys. Thanks for your help in advance. Grant

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Sounds like the tech does not know what he is talking about or is intentionally selling them a bill of goods.
Sounds like the defrost timer or sensor may be the culprit. Get a second opinion, and ask if the tech would have known the unit would fail (if it really has) the next week if he had done a visual inspection before it went out.
You may learn something, if so, consider it an educational expense and step up to the plate.

Even if the unit is broken, things break, an inspection is a snap shot in time of the condition of the property.
I assume the heat worked for 3 days according to your description, case closed.
There is no reason to add refrigerant unless there is a leak.
In fact, the act of adding refrigerant to a system that does not need it can damage the compressor or otherwise cause a system to malfunction.
I do have a couple of concerns with your description of the system operation.
There should not be "ice" on the exterior coil. White "frost" is OK, but clear solid ice should not be present under most circumstances (freezing rain, etc. excepted)
I would normally expect a 20 - 25 degree rise during heat pump only operation.
Your 35 degree rise on heat pump only sounds a little high, but I was not there.
Don't let the first and second stages of supplemental heat fool you into thinking the heat pump is working.
I advance the thermostat only one or two degrees above room temperature (just until the unit starts) and visually inspect the exterior unit for proper function at the same time I take TD readings, then advance the stat to bring on the supplemental.
I will leave the heat pump and supplemental on long enough for every thing to sequence on and expect a substantial TD rise above the heat pump only.
Then I shut down the supplemental with the "emergency heat" switch on the stat if it has one and check the outdoor unit again for shut down and another TD expecting a drop from the "all in" TD.
Good luck.

If it is icing it could also be a refrigerant leak.

I would pay to have my own tech to go and take a look at the system. Then I would compare what my tech and the owners tech said and try to figure it all out.

I'm betting on a refrigerant leak or a bad timer on the defrost cycle. You know the compressor is running as it is making ice. Now, here's another thought. The unit could have burned itself out (dead compressor) and this is now why the tech is saying it needs to be replaced.

Thanks guys for your feed back, I am contacting my A/C tech to have him check out the system. I don't like the idea of the new owner calling a tech then getting scammed by him. Wish I could have had my guy look first. Puts me on the spot. I still don't think I should pay for anything because the unit was working the day of the inspection and 8-days after I inspected the home. Thanks for your help, I will keep you posted.
Grant

Hope this photo is added, picture of heatpump.IMG_0006.jpg

Originally Posted by Grant Harrod

Thanks guys for your feed back, I am contacting my A/C tech to have him check out the system. I don't like the idea of the new owner calling a tech then getting scammed by him. Wish I could have had my guy look first. Puts me on the spot. I still don't think I should pay for anything because the unit was working the day of the inspection and 8-days after I inspected the home. Thanks for your help, I will keep you posted.
Grant

If they did any repairs or replacement without giving you notice then you should be off the hook. As long as that is in your contract.

Tenth Avenue Freeze-Out...

Sorry for the thread drift. Reading this thread got me humming that song.

We now return you to your regularly scheduled broadcast.

Your talking about a 3" band of ice on a heatpump, they do that and then they defrost.
If anything there might be some adjustment needed in the defrost cycle.
The cycle time is adjustable, if you had total defrost failure there would be much more ice than that.
Adjusting the freon charge may also be considered.

Step up to the plate? I dont think so, those were good temp readings.
That fact the return (or inside) temp dropped 15 degrees in 20 minutes raises other questions.
If the temp dropped 15 degrees in 20 minutes, that indicates that the unit was heating the hell out of the place before you shut it down.
As far the tech, he's wrong. From what youv'e stated, all other major components were functional.
Defrost problem at the very least, no new unit.

Kevin,

Step up to the plate? I don't think so, those were good temp readings.

You may learn something, if so, consider it an educational expense and step up to the plate.

If you read my original opinion, there was a big IF, in front of the step up to the plate.
IF your tech tells you that you missed a big problem, etc. then learn from it.
If not, then I agree, the temps and operation as described look pretty good.

By the way, as one of my instructors way back in the dark ages was fond of saying about the meaning of frost on a line, coil, etc. was: "the only thing that frost proves is that the line is or was below 32 degrees." In other words, it is not a diagnostic tool other than a visual confirmation that the line was cold enough to make frost. Don't get fooled into diagnosing based on a little or a lot. It is significant if you have a buildup of solid ice, not frost, which can indicate problems with clearing the coil totally during defrost.

Jim,

I agree, ice vs. frost is a valid point.
What I disagree with the most is the idea that enitre unit would need to be replaced.
If he got good temp readings and all was functional, then his job as an inspector is done. That is, if the frost line was at least noted.Otherwise, diagnosing the defrost cycle or stating weather a functional system should be replaced would be clearly beyond the scope of your average inspection. Therefore, no fault should placed on the inspector in my opinion.

I agree with you Kevin, unless the second opinon guy can give you some definitive evidence (which I doubt) that the HI screwed up.

I appreciate your help you guys, I got in touch with my tech today and we are going to the home on Wednesday to check it out, Thanks again for the support, thats why I joined this link.

Grant

Lennox heat pump manufactured 84. Temps at time of inspection around 30-35 but no partciptation for a couple of days. There was a layer of ice, not frost, cascading out of the bottom of the unit. Looked inside the unit and probably 1 inch deep of ice, not frost, inside across the bottom.

Fan was spinning when I walked up and began my inspection. Spent a minute or two pulling the cover off the nearby disconnect panel. Fan stops spinning. Hear a low noise like the motor is trying but can't turn. Step over and smell electrical burning motor smell. See little wisps of smoke rising. Flip the breaker at the disconnect for the unit. Wait a minute and turn breaker back on. Noise stops, smell stops.

Inside the house was warm 68-70. As completed inspection heard the unit cycle on and off several times so "it got better".

At age 25, the unit is near or past its useful life expectancy. The ductwork is full of holes, tears, sags, gaps, failed connections, etc so a Repair/Replace Item in the report but I would like to know the hows and whys

What are the possible and probable causes of the 1 inch layer of ice inside and cascading out the unit?

Originally Posted by Bruce Ramsey

Lennox heat pump manufactured 84. Temps at time of inspection around 30-35 but no partciptation (precipitation?) for a couple of days. There was a layer of ice, not frost, cascading out of the bottom of the unit. Looked inside the unit and probably 1 inch deep of ice, not frost, inside across the bottom.

Fan was spinning when I walked up and began my inspection. Spent a minute or two pulling the cover off the nearby disconnect panel. Fan stops spinning. Hear a low noise like the motor is trying but can't turn. Step over and smell electrical burning motor smell. See little wisps of smoke rising. Flip the breaker at the disconnect for the unit. Wait a minute and turn breaker back on. Noise stops, smell stops.

Inside the house was warm 68-70. As completed inspection heard the unit cycle on and off several times so "it got better".

At age 25, the unit is near or past its useful life expectancy. The ductwork is full of holes, tears, sags, gaps, failed connections, etc so a Repair/Replace Item in the report but I would like to know the hows and whys

What are the possible and probable causes of the 1 inch layer of ice inside and cascading out the unit?

It is cold outside and the run-off from the defrost of the exterior unit collects at the base and refreezes when the unit switches from defrost back to heating mode.
More modern units will have a delay to allow the water to drain away before going back into the heating mode. Cleaning the drain ports at the base of the unit may help let the water drain away more quickly, but ice on the bottom of the unit won't hurt performance much.
Also, the wisps of "smoke" might have been steam from defrost. During defrost the exterior fan will be turned off with only the compressor running to heat the exterior coil and it can give off an odor.
When you turned off the unit breaker the defrost cycle was likely interrupted and resumed normal operation once you turned it back on.

Thanks for the spell check and answer!

Get in and take care of this fast. fast. fast. Then it will go away...

Best

Ron

Another thing to consider is the balance of the airflow in the ducts and across the EC. I assume the unit is older than 2001 when the SEER requirement was increased to 13. The system may need to be balanced to accomodate the higher efficiency. An older system could have had an efficiency upgrade on the condenser anyway. Also the fan could have been in the "on" position instead of "auto". Also the owners may have damped down some rooms to affect the airflow enough to cause a problem in those conditions.

Patrick Belcher
U.S. Inspect

Originally Posted by Patrick Belcher

Another thing to consider is the balance of the airflow in the ducts and across the EC. I assume the unit is older than 2001 when the SEER requirement was increased to 13. The system may need to be balanced to accomodate the higher efficiency. An older system could have had an efficiency upgrade on the condenser anyway. Also the fan could have been in the "on" position instead of "auto". Also the owners may have damped down some rooms to affect the airflow enough to cause a problem in those conditions.

Patrick Belcher
U.S. Inspect

NOPE
Notice the icing was on the outdoor coil, not the indoor. The outdoor coil in heating mode WILL make frost / ice on any properly operating unit when the outdoor temperatures are cold enough. Indoor air flow will have almost nothing to do with the outdoor coil, neither will SEER rating.