In April of 2006 I had a Carrier Infinity heat pump installed to replace a 15 year old heat pump. It worked great for summer cooling, but almost from the start of the heating season last year, I felt the outdoor unit spent way too much time frosted up. I am not home a lot, but it seemed like a high percentage of the time when I was at home, it was frosted up. I had the installer come out and check it several times and they could find no problems and set the defrost timer to 30 minutes. I still felt it was frosted up too much, but just put up with it. This past weekend it got to the point where it would not defrost at all and by Monday morning the outdoor unit was a huge block of ice.
Here is some info on the unit.
The outdoor unit is a 38YDB048-311
The indoor unit is a FE4ANB006000
The thermostat software version is CESR131339-10
Here are a few of the heat pump settings.
Elec heat lockout-none
Hi coil latch-none
Hi heat latch-off
In checking the run/fault history I found the following:
HP 01/06/2007 temp sensor out of range 52 times as of last Sunday, now at 55 times
HP 10/27/2007 hi pressure switch open 3 events
Under heat pump faults I found:
lo pressure switch open 1 event
hi pressure switch open 1 event
And this morning for the first time I found this:
Outdoor air temp fault- 3 events.
On the advice of the distributor techs, the service man came out yesterday and ohm tested the outdoor temp sensors and said they both test OK, Using the thermostat control, he manually defrosted the heat pump and he says it defrosts just fine. I am not sure he feels that there really is a problem.
When I got home last night the unit had pretty good frost build up on it. I kept an eye on it off and on through the night and I never did see it defrost and it is pretty much solid frost this morning. I am located in Iowa and the temps here this morning are about 15 degrees, not sure of the humidity.
Sorry about the lenght of this.
What is causing the "events" and the failure to auto defrost? Any thoughts on all of this?