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  1. #14
    Join Date
    Mar 2007
    Location
    Myrtle Beach, SC
    Posts
    2,919
    Quote Originally Posted by thorton View Post
    Yes, great info Kevin O'neill and Waterloo!!!! Kevin would you be able to tell me, if a heat pump has a timed defrost to initilize the start of a defrost cycle, what signals the end of the defrost cycle? Is it a preset time or another condition that ends the defrost. I'm just wondering. Lately, my heat pump seems to defrost quicker then other times.

    thorton
    ____________________
    Common sense isn't that common
    Thorton,

    It depends. Most terminate after 10 to 11 minutes max, regardless of coil conditions, but usually there is another way to terminate as well.

    Most (Time/Temperature Defrost) also have a coil thermostat that terminates after the coil warms up to between 60 and 75 degrees.

    Some (with demand defrost) have a coil thermistor that electronically senses the coil and outdoor air, then terminates after the coil warms a certain amount above the outdoor air temperature.

    Trane & York use mostly demand defrost.

    Lennox and Carrier use some time/temperature & some demand.

    Most other brands that I am familiar with use time/temperature terminate.
    Remember, Air Conditioning begins with AIR.

  2. #15
    Join Date
    Apr 2005
    Location
    Kingston Ontario Canada
    Posts
    1,210
    Quote Originally Posted by Kevin O'Neill View Post
    Thorton,

    It depends. Most terminate after 10 to 11 minutes max, regardless of coil conditions, but usually there is another way to terminate as well.

    Most (Time/Temperature Defrost) also have a coil thermostat that terminates after the coil warms up to between 60 and 75 degrees.

    Some (with demand defrost) have a coil thermistor that electronically senses the coil and outdoor air, then terminates after the coil warms a certain amount above the outdoor air temperature.

    Trane & York use mostly demand defrost.

    Lennox and Carrier use some time/temperature & some demand.

    Most other brands that I am familiar with use time/temperature terminate.
    Thank-you, sir!!! Yes, my heat pump is a Carrier 38YZA which is a 410A unit. I knew the defrost initialization was a pre-selected time. I have mine set to defrost every 50 mins. But I didn't know what terminated the defrost. It must be a time/temperature and demand that does it, as you suggested. This particular heat pump seems to be behaving diferently this heating season. My local refridgeration mechanic checked the sub-cooling about a month ago and he added some 410A refridgerant. The heat pump seems to be working really, really great. Better then other years. The condenser is quieter, even less noise in the linesets and like I said seems to be defrosting quicker. This is the first time the heat pump sub-cooling was checked since initial install. Every time previously, it was serviced in cool or cold weather and you know as well as I do that pressures are the only way you can check refridgerant charge in cold weather. So I'm begining to believe that the charge has been incorrect since day one. It's probably my fault, as I never had the heat pump serviced the first 5 years in the warm months. The reason for this is it always worked awesome in cooling mode. All the problams I have had has been when it was in heating.

    Thanks again for taking the time to give me a very good explanation.

    thorton
    _____________________
    My wife always gives sound advice
    99% sound… 1% advice

  3. #16
    Join Date
    Feb 2007
    Posts
    18
    UPDATE

    Just heard back from the contractor, they said my unit needs a muffler that is installed on newer models after Feb '07 (mine was from Jan.) go figure.

    They also said repair has to be done in weather above 60 degrees. I wonder why?

  4. #17
    Join Date
    Jun 2007
    Location
    Metro St. Louis
    Posts
    181
    Quote Originally Posted by kccustom View Post
    UPDATE

    Just heard back from the contractor, they said my unit needs a muffler that is installed on newer models after Feb '07 (mine was from Jan.) go figure.

    They also said repair has to be done in weather above 60 degrees. I wonder why?
    I believe the answer is related to being able to check subcooling and superheat. Both are done in A/C mode, and would have to be done above 60*.

    Pros - What is this "muffler"?

  5. #18
    Join Date
    Feb 2007
    Posts
    18
    Last Update:

    Muffler installed, I can barely hear it running.

    Guy came by and hooked it up while I was at work and had it ready to turn on when I pulled up.

  6. #19
    Join Date
    Jun 2007
    Location
    Metro St. Louis
    Posts
    181
    Quote Originally Posted by kccustom View Post
    Last Update:

    Muffler installed, I can barely hear it running.

    Guy came by and hooked it up while I was at work and had it ready to turn on when I pulled up.
    Is it anything more than a tightly wrapped foam wrapper on the suction line?

    I had my installer out yesterday to finish up some stuff. Found that the unit was overcharged and removed some refrigerant. But, with the temps at 70 yesterday, I was unable to check. It seemed to also help.

  7. #20
    Join Date
    Feb 2007
    Posts
    18
    I will do one better with some picture goodness!

  8. #21
    Join Date
    Jun 2007
    Location
    The Twilight Zone
    Posts
    2,964
    Quote Originally Posted by thorton View Post
    I have mine set to defrost every 50 mins.
    My new Goodman heat pump condenser was set at 60 minutes defrost time. I changed it to 90 minutes.

  9. #22
    Join Date
    Dec 2006
    Location
    Middle Tennessee
    Posts
    11,347

    *

    Quote Originally Posted by gary_g View Post
    My new Goodman heat pump condenser was set at 60 minutes defrost time. I changed it to 90 minutes.
    that was pretty ballsy!



    .

  10. #23
    Join Date
    Jun 2001
    Location
    Louisville, KY
    Posts
    12,189
    Quote Originally Posted by Airmechanical View Post
    that was pretty ballsy!



    .
    Really? I have mine set for two hours.
    Perhaps you should have read the instructions before calling.

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