Results 1 to 6 of 6
  1. #1

    HEAT PUMP DEFROST CYLING TIME

    Have a Frigidaire HP (Nordyne) FT4BE-042K with B5BM-x42K-B indoor unit. Anything below about 40 it goes into defrost every 30 minutes like clockwork. Auxiluary heat (electric) doesn't kick in till after defrost is terminated and stays on till house reaches thermostat set temp. Unit then runs perhaps 10 more min. and shuts off. Thermostat is WR 1F82-261. Am using setback at night, is this wise. Am in Austin, Tx. area. Lot colder than usual. Unit installed 08' new house.
    Is this normal operation? Electric bill last month 194.00. 1800 SF, quite a few windows.

  2. #2
    Join Date
    Oct 2008
    Location
    OFFICES IN : ARIZONA - NEVADA - TEXAS
    Posts
    258
    You've gotta very good system, that will work great whenever the cycle is correct..I've installed alot of this model some are working today and are 15 years in operation with no problems... Follow these steps and your system will be a good kicker !

    1- (on the Outdoor Section ) , make sure coil cleaned well with water only, locate your solid state control board, next to your main line contactor place the defrost sequence to 90 min.

    2- check your thermostat and make sure it is a two stage heat.. Then wire your auxilary heat ( stage 2 ) to your furnace ( Heat strips...)

    Your heat strips are currently cycling your system into a high pressure state and making the system cycle on a high pressure safety overload .. Make sure your indoor air filter and indoor are clean... Your refrigerant gas charge can be checked in cooling cycle once the home has warmed up some.
    "Rock-n-Roll " Ain't noise pollution..

  3. #3
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    33,399
    Yes, the joy of a heat pump with timer defrost. They come factory at 30 minutes but 60 minutes is probably more practical. I have mine on 90 and an doing fine. Got a bit frosty during last weeks near blizzard but still heated fine. Setback at night when below say 40 may cost more than it saves.

  4. #4
    Join Date
    Jul 2008
    Posts
    551
    When is it desirable to change the defrost timer from 30min to 60 or 90? Do you just check it and if it is defrosting w/out ice you lengthen the timer?

  5. #5
    Thanks for reply's. Changed defrost times, no problem. I do not have schematic or diagram for unit. W2 on thermo wired to W1 on air handler and then on to W1 on condenser unit. Have to assume this is correct!? Appreciate your help. A lot more than I got from installer..

  6. #6
    Join Date
    Jun 2007
    Location
    The Twilight Zone
    Posts
    2,964
    Quote Originally Posted by BaldLoonie View Post
    Yes, the joy of a heat pump with timer defrost. They come factory at 30 minutes but 60 minutes is probably more practical. I have mine on 90 and an doing fine. Got a bit frosty during last weeks near blizzard but still heated fine. Setback at night when below say 40 may cost more than it saves.
    I also have mine set to defrost at 90 minutes.

    Never had an issue except for the blizzard of 2/10/10. Noticed the air temp from the registers wasn't normal, so went out and checked the condenser. Found 2/3 of it covered in snow, a nice "snow hat" on the top, and 4 foot drifts around 3 sides. Dug it out and cleaned it off. The entire condenser was frosted over.

    With the frost covering, I was only getting 79F degree air on a 28F day. Normally I would get 90F on a 28F day. Big difference.

    I was thinking about setting the defrost time to 30 minutes during the snowstorm, but I didn't want to fight the drifts and go back out to the condenser again

    Take care.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event