My home came with this unit, a series 2A6B3 with electric furnace, when I bought the home - within a year of its completion in 2007. For the most part we have been ok with it. But over the past few years we have had to make some repairs - at least the following: run capacitor, start capacitor, start relay, and most recently defrost control board. And even with these replacements - to be expected I am sure with a unit this old, we still feel something is not right. Perhaps we are just so confused... Perhaps you can help?
Over time, I have raised the heat pump lockout via our thermostat (a Venstar ColorTouch T7850) from 25 to 30 and then this morning I raised it to 35. I do this since the HP seems to have more and more difficulty keeping up as temps decline. I know this is expected but it seems to grow worse - perhaps with age? To be very sure of things, I have a thermometer on a heater output vent so I can know the air temp coming out as the system runs. This morning with outdoor temp at 35, the heater was running (I could hear it, see it on the Venstar, and feel air coming from the vent) and I checked to see the HP fan not spinning at all (indeed, it had not been running at all due to the low temp). This is exactly as I expected.
But I noticed the temp of the air coming from the vents was cold - 48-50 degrees. I again checked and the HP was NOT RUNNING. This continued for a while (maybe 5 minutes) and then hotter air started coming out again. It was as if the HP was in a defrost cycle (which we always have hated but understand is needed at times). But since the HP wasn't running, this would make no sense, right?
BTW - I know that some HP systems can run the AUX heat during defrost but ours never has and one tech told me it simply could not - no idea why but gathered it was a hardware limitation of some sort.
I don't know if this is related in any way, but when the defrost card (Trane CNT05875 / CNT-5875) was replaced there was alot of confusion over the replacement part lacking some connections found on the old unit (which was, I am sure, original). We ultimately figured out that the old configuration had been revisioned and the new one did not need/want the extra connections. So those were insulated and left dangling.
So can anyone help me understand why what seems to be a defrost cycle (it acts/feels just like it) should be running when the HP is NOT?
Thanks very much?
David
Seattle, WA USA
Over time, I have raised the heat pump lockout via our thermostat (a Venstar ColorTouch T7850) from 25 to 30 and then this morning I raised it to 35. I do this since the HP seems to have more and more difficulty keeping up as temps decline. I know this is expected but it seems to grow worse - perhaps with age? To be very sure of things, I have a thermometer on a heater output vent so I can know the air temp coming out as the system runs. This morning with outdoor temp at 35, the heater was running (I could hear it, see it on the Venstar, and feel air coming from the vent) and I checked to see the HP fan not spinning at all (indeed, it had not been running at all due to the low temp). This is exactly as I expected.
But I noticed the temp of the air coming from the vents was cold - 48-50 degrees. I again checked and the HP was NOT RUNNING. This continued for a while (maybe 5 minutes) and then hotter air started coming out again. It was as if the HP was in a defrost cycle (which we always have hated but understand is needed at times). But since the HP wasn't running, this would make no sense, right?
BTW - I know that some HP systems can run the AUX heat during defrost but ours never has and one tech told me it simply could not - no idea why but gathered it was a hardware limitation of some sort.
I don't know if this is related in any way, but when the defrost card (Trane CNT05875 / CNT-5875) was replaced there was alot of confusion over the replacement part lacking some connections found on the old unit (which was, I am sure, original). We ultimately figured out that the old configuration had been revisioned and the new one did not need/want the extra connections. So those were insulated and left dangling.
So can anyone help me understand why what seems to be a defrost cycle (it acts/feels just like it) should be running when the HP is NOT?
Thanks very much?
David
Seattle, WA USA
source https://hvac-talk.com/vbb/threads/2243943-So-Confused-About-My-American-Standard-Heat-Pump-Setup?goto=newpost
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