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  1. #1
    Join Date
    Jul 2004
    Location
    NJ
    Posts
    1,802
    A produs walk-in was down this morning.
    I got very sick to my stomack on the way to that job accompanied with headache.so I decided to go home after checking that unit,I couldn`t spend anytime with detailed readings ,just wanted to find the problem as practically as possible and get outta there.compressor I believe was a 1.5 hp copeland.when I got there nothing was running.so I started with checking power ,LPC was open,no charge in system.Put some 409 jumped LPC.fan runs nice compressor wouldn`t.checked run and start caps,checked pot relay,checked windings ,nothing wrong.manually tried to start comp.and it starts for a couple of seconds.OL opens.
    the run cap of the fan motor read open,very high MF,also high ohm resulting in open line.removed that 5 MF fan run cap everything runs fine..Put a new cap everything runs fine.fixed the leak at the exp.flare nut etc.Job done..
    I couldn`t spend time to see what happened but would you guys think;
    fan motor was drawing too much current because of bad cap
    and comp.couldn`t start because of OL.But when I Jumped out pot relay it started ,couldn`t run...that doesn`t explain it.




  2. #2
    Join Date
    Jul 2004
    Location
    NJ
    Posts
    1,802
    Originally posted by altan
    A produs walk-in was down this morning.
    I got very sick to my stomack on the way to that job accompanied with headache.so I decided to go home after checking that unit,I couldn`t spend anytime with detailed readings ,just wanted to find the problem as practically as possible and get outta there.compressor I believe was a 1.5 hp copeland.when I got there nothing was running.so I started with checking power ,LPC was open,no charge in system.Put some 409 jumped LPC.fan runs nice compressor wouldn`t.checked run and start caps,checked pot relay,checked windings ,nothing wrong.manually tried to start comp.and it starts for a couple of seconds.OL opens.
    the run cap of the fan motor read open,very high MF,also high ohm resulting in open line.removed that 5 MF fan run cap everything runs fine..Put a new cap everything runs fine.fixed the leak at the exp.flare nut etc.Job done..
    I couldn`t spend time to see what happened but would you guys think;
    fan motor was drawing too much current because of bad cap
    and comp.couldn`t start because of OL.But when I Jumped out pot relay it started ,couldn`t run...that doesn`t explain it.



    what?

  3. #3
    Join Date
    Feb 2004
    Location
    Medford Oregon
    Posts
    807
    you say you checked winding resistance
    does that mean you compared readings against specs in Copeland's electrical handbook or just continuity. What you've described is more than likely bad windings, and continuity doesn't show that.

  4. #4
    Join Date
    Jun 2004
    Location
    Long Island, NY
    Posts
    37
    You statement "I jumped out the pot relay, it started but couldn't run"? (not sure what you mean). On the pot relay did you jump accross terminals 1&2 (contacts N/C at startup) If so the pot relay contacts are not closed for start up,is staying open (no start cap in circuit) and relay should be replaced.
    Note: Pot relays are difficult to check. Should always be replaced when a start cap is replaced. Allways replace pot relay w/the exact size for that compressor.
    The cond fan motor having a bad run cap,(you replaced) should have been going off on its own internal mtr overload and should not have an effect on the compressor amps or comp overload.As stated in other reply, Checking a motor windings for resistance while off, does not account for induced voltages (EMF) while mtrs running.

  5. #5
    Join Date
    Jul 2004
    Location
    NJ
    Posts
    1,802
    Originally posted by jackmm1
    You statement "I jumped out the pot relay, it started but couldn't run"? (not sure what you mean). On the pot relay did you jump accross terminals 1&2 (contacts N/C at startup) If so the pot relay contacts are not closed for start up,is staying open (no start cap in circuit) and relay should be replaced.
    I meant I took the wire from #1 terminal touched it on #2.and removed it.
    I was suspecting that for some reason the back emf was not enough to open #1 to #2.As I stated before I wasn`t in good shape at that job and I may be mistakening as to the order of things I did.but the bottom line that I wanna know is removing the open cap of the fan was what allowed the compressor to operate.since compressor was working with the same components its obvious that the pot relay was good anyway.no call-back yet..

  6. #6
    Altan, this happens to the very best of us here.

    Most of us though, wouldnt exactely admit to it though!

    We wait to see some new guy come along and make a relevant post andthen we jump in and make comments.



    (jus kidding) We all do make mistakes.
    As time moves on, we just make bigger ones!

    Hey ... just look at DiceMen. He used to be a pretty straight guy.

    But now that he took up goat herding .... he is all bent outa shape.
    In fact, there is a crooked picture of him on a roof top, bent crooked, and with very hairy legs.


    Just try to remember to keep things simple. Read over the thread on troubleshooting. It is fantastic.



  7. #7
    Join Date
    Jul 2004
    Location
    NJ
    Posts
    1,802
    Originally posted by jackmm1
    Pot relays are difficult to check.
    I would check #1 and #2 if its NC.The wire that comes to #1 from start capacitor I would put my amp probe to it.if compressor starts I should see the amp draw stop after start.also #2 and #5 could be ohmed out to see a high ohm value,which could be compared with a good one`s value.

    thats why I was hoping someone would tell me how an open cap in the circuit did effect the start caps value on the start up.

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