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O/T. Heat pump operation questions

TJ in KY

TJ in KY

Member
I am not real familiar with heat pump operation and was wondering if it was normal for the air handler fan to run all the time. Example is that if set point is reached the air handler fan continues to run. This occurs even in emergency heat mode with compressor off. The auxiliary heat (electric coils) will cycle on and when set point is reached they will go off, but fan will continue to run, as house cools down fan continues to run moving air until aux heat kicks in again.
It has run continuously without aux coming on for a half hour or more after set point is reached.. Just seems to me that if set point is reached coils (or heat pump) should turn off and air handler should shut off within a few minutes after coils cool off. If I lower set point it will do that, all off after a few minutes

Tech has determined that when the heat pump switches to defrost cycle it just shuts down and advised me to run in emergency mode if heat is needed.
Waiting on control board to come in, running on emergency mode in mean time.
 
Some controllers are programmed to run the circulation fan all the time. many people feel that temps stay more even when continually stirred. There is usually a swithc (not on all) that allows fan cycle adjustment. Jim
 
Look for a fan switch on the thermostat. It should be labeled Fan. OFF allows fan to operate only when the outside unit or the emergency heat is operating. ON allows the fan to operate continuously
 
Pull the low voltage wire off "G" terminal on air handler. Blower should stop running. Some have a time delay and blower may run for about a minute to minute and a half. If blower stops problem is not in air handler. If it doesn't stop may be stuck fan relay. What brand equipment do you have and is the thermostat digital?
 
On mine, there is a switch labeled FAN- with 2 positions, ON and AUTO. ON runs all the time, AUTO goes on and off with the unit. It runs about 2 minutes after the heating or cooling stops, to take advantage of the ambient heat or cooling on the exchanger.

When it gets cold and we have the wood stove going, I switch it to ON so it circulates the wood heat. Keeps the whole house nice. However, when we're running the wood stove because the power goes out, it doesn't seem to work as well. Need to look into that. . .
 
I do have digital thermostat Honeywell, and the outside unit is a Lennox. The fan switch has 2 positions ON and AUTO and has been set to AUTO.
I don't think it is a stuck relay, as it shuts off after 1 min. when I lower set point temp below room temp but will check that.
After watching it I was wondering if digital thermostats have a "deadband" it seems like it is never satisfied even when both thermostat and set point are the same on the display. In emergency mode ( compressor locked out) display shows "heat on" and fan will be on and then display will show "auxiliary heat" going off and on and that is when fan never goes off unless I lower set point.
Could it be a thermostat problem? Displaying 72 but not really satisfying internally and shutting down unit. I hope this is clear maybe it is not a problem at all, and auxiliary heat is sized too small.
 
I bought a Goodman furnace about 15 years ago. The fan just
comes on at times even with the whole system off . The only
way to stop it is to flip the breaker. The dealer sent a tech out
about 6 times under warranty and never did find what was
wrong. I've been working in the house between renters and it
is still doing it. I will just live with it until I have to replace the
system.
 
the answer is no...when in heat mode you should have the heat pump and furnace together, if the heat pump can't make enough heat the furnace should kick on and take over, in emergency mode on thermostat you should have only furnace working and fan on heat pump should not run at all,..if you go to fan on thermostat your furnace fan will run all the time...i'll say right now my heat pump does not have the heat strip in it..
 
I agree it should not run all the time. That said,
my sons father in laws dad. (a heating and air man
all his life) Though you should run your fan 24-7.
I have a Coleman heat pump that I added to a 40 yr
old LP furnace. Have changed it to a manual
thermostat. It will stay in heat pump mode till I
change it. It will actually heat the house down to
20 or so in this mode, but will freeze of and go
into airconditioner mode to thaw out. Mean while
the temp inside will go down to 67 to 68 then will
reverse itself and heat the house back up to 72.
Our fan comes on when the compressor starts and
turns off about 1 minute after it stops. In
Emergency mode (LP) The fan doesn't come on till
the bonnet is hot and turns off after it has
cooled off. I don't think ours has but a 13 seer
no. but our Light bill was just 177 dollars last
month. We have the new meters, so aren't behind a
month. We also have a heat pump water heater. I
think it runs 20 hrs a day, but sure is cheap! Vic
 
Most Honeywell thermostats will keep the fan on until temperature gets 1 degree above setpoint. Sounds as if your electric strip heat is undersized as you say and never reaches the 1 degree above setpoint. Also the thermostat setup program may need to be reprogramed. Sounds as if you don't have a problem with your air handler. When the outdoor unit goes into defrost the outside fan will shutdown and the electric strip heat will come on. The outdoor compressor will continue to run in cooling mode to melt ice off outdoor coil. Should not stay in defrost over five minutes .
 
mine also works this way; fan kicks on 2 minutes before the heat, stops 2 minutes after heat goes off.
 
Thanks for all the replies, HVAC tech coming tomorrow with new board for compressor problem. It seems like air handler fan comes on in emergency heat mode but electric strips do not come on and fan keeps running blowing room air around(like heat pump is in loop) .
Example if room air and set point are same 66 degrees the heat on indicator comes on (like when heat pump should start but it is in emergency mode) and fan blows and blows. If I raise set point aux will kick on and heat rooms. When temp gets to new set point aux goes off but fan keeps running It seems like system still thinks heat pump is in loop and continues running (but no heat) I don't it should, not if in emergency mode. Will check with tech tomorrow. Thanks again for all replies
 
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