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Heat pump auxiliary/emergency heat

559 Views 11 Replies 3 Participants Last post by  ServiceCall
I have a Heil heat pump. During most of the winter, it works fine. At the tail end, though, around this time of year, the heat strips don't work properly. When using auxiliary/emergency heat, the strips will heat up for about 5 minutes or so, then shut off, and not come back on. If I turn the unit off and then back on, it'll do the same thing. They will heat up for a few minutes, then no more. During the rest of the winter, they do fine, even if running constantly on emergency heat. After summer, it works fine until right around the last cold spell of winter. This causes the house to cool down, of course, and then the thermostat just tries to run auxiliary heat, so basically no heat. This has been happening for the last couple of years. I replaced the thermostat the first time it happened, but it still does it. I have also tried turning it off for a day or so, but that didn't help either. Any ideas or help with this would be much appreciated.
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Check and see if they are calling to run, with your meter.
Both of the terminals W1 and W2 are receiving around 26 V AC. I believe W1 is the pump and W2 is the strips if I remember correctly.
Y and O are the heat pump. W1 and W2 are the heat strips.
I checked them against C - is that correct?
Should get voltage to C, no voltage to R, when it’s calling.
Yes, that is what it's testing. I also know that it's calling for it, because if I turn the unit off and then back on, the strips will come on, but shut off after about 5 minutes. It is still calling for them after they shut off.
It's frustrating, because it only happens in this small window of time. It's always at the last cold snap of winter. It's going to drop to 26 degrees tonight, and then warm back up and turn back into spring. When I use it again next winter, going by the past few years it will work fine until right before spring again. So, apparently, not running it for awhile resets something. I'm not sure how long that while is, though. I left it off for about 36 hours last time, same problem, but summer fixes it. I'm afraid that calling a technician in will find no problem because it has been off for long enough to work again, as has happened before. It basically comes down to checking it in the 24-48 hour time period of the last cold snap to figure out what's going on. Meanwhile, my family and I freeze into spring.
Are you certain the problem isn’t with the heat pump, and the heat strips are actually working ok?
When the heat strips are calling what amperage are they pulling?
Oddly enough, my meter isn't showing any amperage. I have it set in circuit with the terminal, like it's supposed to be with this meter, but it's only showing 0. That being said, there is a marked difference between when the strips are running vs. the pump as far as the amount of heat. With the heat pump, it heats the house, but the air coming from the vents feels like room temperature. Whereas when the emergency heat is on, the air is hot. If I turn the unit off and then back on, you can feel the hot air from the ducts, but it only lasts about 5 minutes, then blows cold. With the warmer air outside that we had today, I can slowly heat the house up using the pump, but can only turn it up a degree or two before it starts trying to use auxiliary heat, then just blows cold. So, I can set it to one degree over the temp of the house, then when it warms up to that, one degree more, and so on. Once it tries to turn the auxiliary heat on, it just blows cold air unless I turn it off and back on, then again heat for about 5 minutes. If it dips below around 40 degrees outside, then of course the heat pump cannot keep up, ,so it automatically tries auxiliary heat again, and everything just starts over.

Sorry for the long post, I hope it makes some sort of sense. If I can find my other meter, I'll try to check the amperage again with it, but it seems like the heat pump is working since it does (slowly) heat up the house as long as the auxiliary heat doesn't try to turn on.
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What do you mean by having the meter “in circuit” to check amperage? You will need a clamp amp meter to check that current.
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