Ask Me Help Desk

Ask Me Help Desk (https://www.askmehelpdesk.com/forum.php)
-   Heating & Air Conditioning (https://www.askmehelpdesk.com/forumdisplay.php?f=150)
-   -   Heat Pump will not shut off (https://www.askmehelpdesk.com/showthread.php?t=103418)

  • Jun 22, 2007, 08:28 AM
    shoe
    Heat Pump will not shut off
    I have a Bryant heat pump that was used very little over the winter. When I went to turn on the air conditioning a few days ago, the outdoor unit would not come on, but the indoor fan and thermostat appeared to be working fine.

    I checked the contactor and it was not pulling in, when I pushed it in, the unit kicked on, but would not shut off when I turned it off at the thermostat. I had to cut the power to turn it off as to not damage the compressor.

    I replaced the contactor with an identical contactor from the Bryant dealer. It was definitely bad. When I turned the power back on to the outdoor unit, it would not shut off, even when the contactor is not pulled in and the thermostat is off. I had to cut the power again.

    I am 100% sure that I replced the wires correctly on the new contactor. What is the next logical thing to check?

    Thanks,

    Scott:confused:
  • Jun 22, 2007, 08:43 AM
    esquire1
    What continues to run? The compressor and the fan or both? If only the fan, it could be the defrost relay. Just ran into this problem recently.You are sure it's wired correctly? Just verifing
  • Jun 22, 2007, 09:14 AM
    shoe
    Quote:

    Originally Posted by esquire1
    What continues to run? The compressor and the fan or both? If only the fan, it could be the defrost relay. Just ran into this problem recently.You are sure it's wired correctly? Just verifing

    Thanks for the response.

    It is the outdoor compressor and the outdoor fan that continue to run even when the thermostat is not on. I cannot turn off the outdoor unit off unless I trip the breaker. The outside contactor is not pulled in while it is running.

    I can turn the inside fan off by turning off the thermostat, but the outside unit continues to run. If I turn the breaker back on outside, the outdoor unit will still start up immediately even when the thermostat is off and the contactor is out. Very strange!

    I wired the new contactor the same way the old one was wired. I moved the wires one at a time to be safe. I even snapped a picture before I switched it. This unit was operational last year, and nothing else has changed.

    Scott
  • Jun 22, 2007, 09:42 AM
    esquire1
    You are sure that the compressor is also running? You hear it run? You put your hand on it and it's hot and you feel it running? Not trying to be rude but just trying to help you get it going.
  • Jun 22, 2007, 11:06 AM
    shoe
    Quote:

    Originally Posted by esquire1
    You are sure that the compressor is also running? You hear it run? You put your hand on it and it's hot and you feel it running? Not trying to be rude but just trying to help you get it going.

    I will double check when I get home tonight. It sounded like it was running. I will have to pull back the cover on it when I get home in a few hours and see if I feel it running and it is warm.

    I do know that more than just the fan was running. I assumed that the other louder noise coming from the unit was the compressor. It sounded like it did when it worked last year and I listened to the neighbors unit and it sounded the same.

    Thanks,

    Scott
  • Jun 22, 2007, 11:59 AM
    esquire1
    When you have the cover off, also look at the wiring coming from the compressor and fan and double check them. Be sure they are connected to contactor opposite end as the 220 volts coming from the disconnect. In other words. You will have 220 volts at the bottom of the contactor and 0 volts at other end with contacts open. When 24 volts pull the contactor in, 220 volts at both ends. It is this end where power should be delivered to compressor and fan. I hope I have not confused you now.
  • Jun 22, 2007, 12:26 PM
    shoe
    Not confused at all. I have the fan and the compressor cables plugged into the opposite end of the source as they were. Here are some pictures (with old contactor). I have it hooked up exactly the same as the new one though.

    http://www.shoemaker.us/temp/panel1.jpg
    http://www.shoemaker.us/temp/panel.jpg

    I will retrace all of these cables to see if I can figure how this fits together. When I get home. I will check the voltage at the top with the contacts open.

    Thanks,

    Scott
  • Jun 22, 2007, 03:19 PM
    hvacservicetech_07
    That is a single pole contactor, so you will have 120 volts at the top all of the time, the contactor only breaks one leg. Take a picture of the schematic and post it if you can.
  • Jun 22, 2007, 04:42 PM
    shoe
    Quote:

    Originally Posted by hvacservicetech_07
    Take a picture of the schematic and post it if you can.

    Yes, it is a single pole contactor. Here is the schematic picture.

    http://www.shoemaker.us/temp/schematic.jpg

    Also, I have again verified that the compressor and fan are both running with the thermostat off and the contactor open.

    Thanks again for the help!

    Scott
  • Jun 22, 2007, 06:21 PM
    T-Top
    You may have a bad crank case heater on the compressor. Undo the wires that go to it.the two black wires that go to the bottom of the compressor.One goes to L1 and the other to 21 on the contactor. If the compressor heater goes bad it can keep 240 volts on the 21 and 22 side of the contactor. It turns into a jumper wire from L1 to 22 and makes the unit run all the time.
  • Jun 22, 2007, 08:33 PM
    shoe
    Quote:

    Originally Posted by T-Top
    If the compressor heater goes bad it can keep 240 volts on the 21 and 22 side of the contactor. It turns into a jumper wire from L1 to 21 and makes the unit run all the time.

    From looking at the diagram, this makes sense. Interesting. I will go out and try it when it is daylight. If this is the problem, what is the approximate cost of replacement, and is it easy to change out?

    After I unplug the heater, and if the unit is off when I turn on the breaker (as it should be with the T-stat off and the contactor open), should I try to kick it on at the T-stat to see if the contactor pulls in and it turns on?

    Thanks a lot!

    Scott
  • Jun 22, 2007, 08:51 PM
    T-Top
    You got it right my man. But remember this is a test(trial and error). Yes you can get a wrap around compressor heater from any hvac supplier and wire it back in the same way. Good luck.
  • Jun 22, 2007, 08:54 PM
    hvacservicetech_07
    Did you by chance test any voltages yet?
  • Jun 22, 2007, 09:02 PM
    T-Top
    The voltage at 21 and 22 has to be 240 volts or it would not be running. The question is why is it with out the contactor closed.
  • Jun 22, 2007, 09:05 PM
    hvacservicetech_07
    I see your point, but aren't crankcase heaters usually wired to L1 and L2, otherwise, what would be the point? It almost sounds like the contactor is shorted, Ive looked at the pictures, everything looks right...
  • Jun 22, 2007, 09:23 PM
    hvacservicetech_07
    Ok, I'm looking at the contactor right now, there is nothing on L1 and L2 besides line voltage, so there doesn't seem to be any way for a crankcase heater to be feeding voltage through, in my opinion the only way it's getting power is a shorted contactor, how else could it be getting 240 volts at 21 and 22?
  • Jun 22, 2007, 09:25 PM
    T-Top
    If the crankcase heater was on L1 and L2 they would be on all the time no need to be heating and adding extra amps after the compressor is running.
  • Jun 22, 2007, 09:29 PM
    hvacservicetech_07
    T-Top, am I looking at this wrong though? Do you see anything else on L1 or L2? I must be over looking something, unless the contactor is really pulling in...
  • Jun 22, 2007, 09:30 PM
    T-Top
    Keep looking check out the wire schematic he sent.
  • Jun 22, 2007, 09:31 PM
    hvacservicetech_07
    Any time I add an after market CCH ,I always install it on L1 and L2 exspecially if it's just air conditioning running all winter, otherwise you'd have a compressor trying to start with cold oil?

  • All times are GMT -7. The time now is 03:52 AM.