Heat Pump issues

Discussion in 'HVAC Heating & Cooling' started by mlblevins, Mar 7, 2007.

  1. mlblevins

    mlblevins New Member

    Dec 9, 2006
    Hi all - I'm in a house that I've owned for about a year now and went through last winter without a hitch with the heat pump, which is about 5 years old. This winter, starting in late December or early January, I started having problems. It's a Carrier heat pump, with the air handler inside and condenser unit (or whatever it's called) outside. I've always had natural gas forced-air and this is my first heat pump (side note - no matter how "good" they're supposed to be, heat pumps are absolute crap compared to gas forced-air systems).

    Anyway, I noticed odd sounds one night and realized the next day that the fan motor (outside) was shutting off and then coming back on before the fan blade had even stopped spinning. Sometimes this will happen only occasionally, but at other times it will cycle on and off every few seconds, repeatedly. It's annoying, sure to damage the fan motor (if it's not already shot) and highly inefficient. It is a struggle to keep the inside temperature at 64 degrees now.

    In briefly talking with an HVAC guy, he noted that heat pumps go into a defrost mode. That brings me to another important point - back in the Fall, when the thing was actually working properly, I could see that the outside unit was frosting up - it would then stop and defrost and re-start. Now, in the dead of winter, there is NEVER any frost on the outside of the unit. I mean not even the slightest hint. I've also noticed that the green light on the thermostat (indicating that electric heating elements are "on") is on much more often and almost constantly if I want to keep the temperature at what I now consider a "balmy" 66 degrees.

    I'm going to call an HVAC tech. of course, but was wondering if anyone has encountered this problem or perhaps knows what it could be. Any advice or input is most welcome.

  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    You might have lost some refrigerant. A heat pump basically becomes very inefficient (assuming an air source version) as the temperature drops, getting to the point where it can't efficiently pull much of any heat from the outside air. That is when the resistance heat gets turned on.

    I prefer the higher outlet temp of a normal furnace. Actually, I really like in-floor radiant heat. One thing you may be able to do is reset the air handler fan speed slower in the winter. That gives the air a chance to heat up a little more on the pass, and you don't feel as cold from the breeze.
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  4. jimbo

    jimbo Plumber

    Aug 31, 2004
    San Diego, CA
    As the outside temp falls towards 30, heat pumps start losing the ability to work, and I believe most are not working at all below 25º.

    It does not sound like you have any problems with your unit. This is a good thing, because assuming your outdoor unit is 10 SEER, when it has to be replaced you will also have to install a complete new indoor air handler. It is not possible to put a 13 SEER heat pump on an older coil.
  5. Rancher

    Rancher Guest

    Also during the winter months it tends to be colder, which means drier air, so not as much frost, or freezing up.

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