We have a heat pump, and it is relatively cold right now (28F). The
heat pump has been running continuously for several hours. (Sometimes
the emergency heat came on.) Then a few minutes ago the machine
started making a different sound. I went out to check it, and a
mechanical sound is coming from the compressor, but the compressor fan
had stopped running. I turned off the unit at the thermostat, but the
sound is still coming from the compressor.

Is this normal? Is it the defrost cycle?
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On Sat, 15 Jan 2011 08:30:34 -0500, "Dimitrios Paskoudniakis"
wrote:

Yes. Everything is normal, that is the defrost cycle.

Yes, it went back to normal a few minutes after I wrote the message.

In your case, if the compressor is running continuously and occasionally
auxiliary heat comes on (but not frequently), you're fine.

The emergency heat was on from time to time.

and heat is pulled from the home to heat the outdoor unit. You will see
steam come out.

Yes I did.

After 5-10 minutes the defrost cycle ends and the
compressor turns back on.

Seemed like it was probably more like 15 minutes, but I didn't time
it.

Now, that your unit runs for extended periods might mean your unit is
undersized for your home for the temperature you have the thermostat set to.
What temperature is your thermostat set to ?

It was set to 73.

Also do you have a digital programmable thermostat ? If not, DO NOT
manually adjust your set temperature up and down, as by raising the set
temperature you will kick on auxiliary heat. Set it and forget it.

I have it set to automatically warm it by 1 degree at 6AM and 1 more
at 7AM, or something like that. If I warm by 1 degree at the time the
emergency heat doesn't come on. By 2 degrees, it does.

How well is your attic insulated ?

Relatively well, I believe. But it is rolls of fiberglass. The newer
stuff would be better.

Thank you for all of the information.
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Jan Philips wrote:

We have a heat pump, and it is relatively cold right now (28F). The
heat pump has been running continuously for several hours. (Sometimes
the emergency heat came on.) Then a few minutes ago the machine
started making a different sound. I went out to check it, and a
mechanical sound is coming from the compressor, but the compressor fan
had stopped running. I turned off the unit at the thermostat, but the
sound is still coming from the compressor.

Is this normal? Is it the defrost cycle?

Normal deice cycle on the heat pump.

The aux heat will come on under two conditions:

- Aux heat will be used if the heat pump isn't providing enough heat and
the thermostat determines that the temp isn't rising fast enough. In
this case you will see aux come on partway into a heating cycle and
remain on until the end of that cycle.

- When the heat pump is running and it's controls determine it's time
for a deice cycle, the heat pump controls will enable the aux heat for
the duration of the deice cycle so that the house continues to warm even
though the heat pump is briefly operating in cooling mode to deice it's
outdoor coils. In this case you'll see the aux on, the heat pump
compresser whirring, but the outdoor fan off. When the deice cycle
completes the outdoor fan will come on with a whoosh of steam and the
hear pump will switch back to heat mode which makes more whoosing noise.

"Jan Philips" wrote in message
...
On Sat, 15 Jan 2011 08:30:34 -0500, "Dimitrios Paskoudniakis"
wrote:


Now, that your unit runs for extended periods might mean your unit is
undersized for your home for the temperature you have the thermostat set
to.
What temperature is your thermostat set to ?

It was set to 73.


That seems much too high to me for a heat pump if you want to limit
auxiliary heat. I wouldn't set it higher than 68 at its warmest, and say 62
overnight and while at work during the day, using a digital programmable
thermostat (not manual changes). If you don't want to use a programmable
thermostat, keep at 68. Or lower. Don't adjust it if you don't have a
digital programmable thermostat.

Your heat pump is running all the time because you have the temp set too
high for its capacity. It is running normally, but if you want 73, you're
going to have to accept it running all the time and occasionally needing
auxiliary heat, and the resultant electric bill.

On Sat, 15 Jan 2011 11:16:32 -0600, "Pete C."
wrote:

- When the heat pump is running and it's controls determine it's time
for a deice cycle, the heat pump controls will enable the aux heat for
the duration of the deice cycle so that the house continues to warm even
though the heat pump is briefly operating in cooling mode to deice it's
outdoor coils. In this case you'll see the aux on, the heat pump
compresser whirring, but the outdoor fan off. When the deice cycle
completes the outdoor fan will come on with a whoosh of steam and the
hear pump will switch back to heat mode which makes more whoosing noise.

Does it do this de-ice cycle in summer too? Because it reminds me of
a problem I had with another heat pump in the summer about 1-1/2 or
2-1/2 years ago. The compressor fan would quit running, hot air (not
just room temp) would start coming out of the vents, and the copper
tube that is supposed to be cold would be almost too hot to touch.
This would happen many times per day.

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On Sat, 15 Jan 2011 13:24:16 -0500, "Dimitrios Paskoudniakis"
wrote:

That seems much too high to me for a heat pump if you want to limit
auxiliary heat.

My family doesn't like it any colder. It doesn't normally use aux
heat unless it has to warm up at least 2 degrees or if it is in the
mid-20s F outside.

Don't adjust it if you don't have a
digital programmable thermostat.

It is a digital programmable thermostat.
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On Sat, 15 Jan 2011 23:51:29 -0500, Jan Philips
wrote:

My family doesn't like it any colder. It doesn't normally use aux
heat unless it has to warm up at least 2 degrees or if it is in the
mid-20s F outside.

For instance, it is 35F outside right now and the heat pump isn't
running at all. (It has been running some.) When it was 25F it ran
all night.
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On Jan 15, 1:24*pm, "Dimitrios Paskoudniakis"
wrote:
"Jan Philips" wrote in message

...

On Sat, 15 Jan 2011 08:30:34 -0500, "Dimitrios Paskoudniakis"
wrote:

Now, that your unit runs for extended periods might mean your unit is
undersized for your home for the temperature you have the thermostat set
to.
What temperature is your thermostat set to ?

It was set to 73.

That seems much too high to me for a heat pump if you want to limit
auxiliary heat. *I wouldn't set it higher than 68 at its warmest, and say 62
overnight and while at work during the day, using a digital programmable
thermostat (not manual changes). *If you don't want to use a programmable
thermostat, keep at 68. *Or lower. *Don't adjust it if you don't have a
digital programmable thermostat.

I'd add that the above is good advice provided it's a smart/
intelligent
thermostat that has adaptive recovery, meaning you set it for the time
and
temp you want and the thermostat figures out when to start the system
to reach the new temp. With a non-intelligent one, even if it's
digital,
when it gets to a new temp/time period, it's just going to do the same
thing as it would if you manually raised the temp setting. The
adaptive
recovery type will figure out how much earlier to start the system up
so
that the heat pump alone can get it to the desired temp, assuming it's
possible, without using backup.



Your heat pump is running all the time because you have the temp set too
high for its capacity. *It is running normally, but if you want 73, you're
going to have to accept it running all the time and occasionally needing
auxiliary heat, and the resultant electric bill.

Jan Philips wrote:

On Sat, 15 Jan 2011 11:16:32 -0600, "Pete C."
wrote:

- When the heat pump is running and it's controls determine it's time
for a deice cycle, the heat pump controls will enable the aux heat for
the duration of the deice cycle so that the house continues to warm even
though the heat pump is briefly operating in cooling mode to deice it's
outdoor coils. In this case you'll see the aux on, the heat pump
compresser whirring, but the outdoor fan off. When the deice cycle
completes the outdoor fan will come on with a whoosh of steam and the
hear pump will switch back to heat mode which makes more whoosing noise.

Does it do this de-ice cycle in summer too? Because it reminds me of
a problem I had with another heat pump in the summer about 1-1/2 or
2-1/2 years ago. The compressor fan would quit running, hot air (not
just room temp) would start coming out of the vents, and the copper
tube that is supposed to be cold would be almost too hot to touch.
This would happen many times per day.

I cooling mode, if the unit isn't sized properly or there is restricted
airflow from a clogged filter, the indoor coil can ice up. The systems
usually don't have the same type of monitoring and deice cycle to clear
that problem, but if it does occur it will cause some issues with the
system.

On Sun, 16 Jan 2011 04:28:45 -0800 (PST), wrote:

I'd add that the above is good advice provided it's a smart/
intelligent
thermostat that has adaptive recovery, meaning you set it for the time
and
temp you want and the thermostat figures out when to start the system
to reach the new temp.

Yes, it is like that.
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