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  1. #1
    Join Date
    Dec 2011
    Location
    British Columbia, Canada
    Posts
    53

    Hmm Only does it when I'm not there...

    So, I was sub-contracted by a guy who installs heat pumps but can't hook them up, set them up, or service them. There's lots of these guys out there. At least they're subbing out rather than attempting themselves.

    I went to a year old install and found that the heat pump ran short cycles, didn't provide heat, and as the homeowner put it,"released condensation from the condensor periodically".

    I found that the wrong piston was installed and that the blower speed was set too high. I also found that their furnace blower was set to run for 3, 30 minute periods in the morning which made them think it was another heat cycle. All is well now except for this "release of condensation" problem. I haven't been there for a few weeks but I was happy with the sc, sh, and delta T. I'm sorry but I don't remember the specifics. I do remember that the return was brought in through the right side of furnace which I don't like, especially since it is trying to move 1600 cfm.

    All I can think of, is that it is a defrost cycle but it was 50 degrees outside. Customer said he was working outside and the unit ran for about 10 minutes, shut off, about 10 seconds later it "released a cloud of condensation" and sounded like it was "bogging" or trying to get going again, and then did start up again for 5 minutes and finished heat cycle.

    Thoughts??????

  2. #2
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    Defrost cycle.
    At 50ºF outdoor temperature, the coil will be operating just below freezing, and well below the dew point if it is humid out.
    If it has time and temperature defrost, the unit will go into the defrost mode every time the timer is up and the defrost thermostat is closed, which typically happens around 27ºF.
    If more government is the answer, then it's a really stupid question.

  3. #3
    Join Date
    Sep 2011
    Location
    Vancouver, WA
    Posts
    252
    10 minutes is generally the default time for most defrost boards. At 50deg, 10 minutes sounds too long for a defrost. The high pressure switch could be opening shutting off the compressor. Check the defrost termination stat. The other possible reason could be the unit has a soft defrost termination, this feature would stop the compressor before shifting the reversing valve. This was to reduce the end of cycle whoosh when the reversing valve shifted.

  4. #4
    Join Date
    Dec 2011
    Location
    British Columbia, Canada
    Posts
    53
    Can you explain why 10 minutes sounds too long for a defrost at 50 degrees? I don't understand.
    It's a goodman 13 SEER. Just deleted my pics of model and serial a couple days ago because I thought all was well after this long without hearing from the customer.
    Mark: time and temp defrost? Do you mean that regardless of the OD ambient, if the unit runs for a certain length of time, it will go into defrost?

  5. #5
    Join Date
    Mar 2007
    Location
    Myrtle Beach, SC
    Posts
    2,919
    Sounds like a shorted defrost thermostat. 13 Seer units usually do not run a coil that mmuch colder (20 degrees) than outside.
    Remember, Air Conditioning begins with AIR.

  6. #6
    Join Date
    Jul 2011
    Location
    East coast USA
    Posts
    960
    wait until it early morning when its not looking and sneak up on it. When it does it again. you Jump out and catch it...HA haaa gotcha..

  7. #7
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    Quote Originally Posted by HomesteadHVAC View Post
    Mark: time and temp defrost? Do you mean that regardless of the OD ambient, if the unit runs for a certain length of time, it will go into defrost?
    If the defrost thermostat is closed, yes, it will go into defrost every time the timer is up, usually either 30, 60, or 90 minutes.
    The defrost cycle lasts until the defrost thermostat opens, typically in the 65-70º range, or for 10 minutes, whichever comes first.
    If more government is the answer, then it's a really stupid question.

  8. #8
    Join Date
    Dec 2011
    Location
    British Columbia, Canada
    Posts
    53
    Thanks Mark, I'll have a look at the board. I haven't looked at this one yet. The heat pump may be working just fine. It's worth one more look to satisfy the customer and to educate myself more.

  9. #9
    Join Date
    Jun 2012
    Posts
    14
    sounds like its working normally...does it have a quiet shift dip switch or dip pin which stops the compressor when shifting the rev valve during defrost

  10. #10
    Join Date
    Nov 2001
    Location
    east kansas
    Posts
    8,024
    At least they didn't call and say it was on fire when the steam raised from the unit.
    Beware of advice given by some guy on the Internet.

  11. #11
    Join Date
    Dec 2011
    Location
    British Columbia, Canada
    Posts
    53
    I'll look for the dip switch this week.
    Milk Man-haha, yeah, it could have gone that way I guess.

  12. #12
    Join Date
    Jun 2012
    Posts
    14
    on carriers it says quiet shift on armstrong air it is a pin you take off that says delay...

  13. #13
    Join Date
    Dec 2011
    Location
    British Columbia, Canada
    Posts
    53
    And on Goodman?

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