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delayed start on compressor


a customer has a 5 ton rheem (corsaire) unit. I think the unit is somewhat over sized for the house. a couple or 3 years back I changed the compressor, I forgot why.

       anyway current problem is, every 5 or six times the contactor pulls in there is a delayed start (about 15 seconds) of the compressor. I didn't have an ammeter on it when it happened. my first thought was the compressor may be getting tight but I realized if it had been stuck for 15 seconds it would have tripped the breaker or opened on internal overload. but it runs fine otherwise the entire summer. the homeowner was the one who noticed the condenser fan going on but sometimes the compressor had a long delayed start.

       I noticed the contactor looked pretty burnt up so I changed that and thought that fixed the problem. the first 5 times I pushed the contactor in both the condenser fan and compressor started right up, the 6th time only the condenser fan came on, the compressor came on 10 or 15 seconds later. I made sure the pressures equalized in between my pushing the contactor in (with a screwdriver).

       I'm going to change the 45 / 5 run capacitor even though there seems to be nothing wrong with it. I checked each side with an analog ohm meter set on the highest scale and both the fan side and the herm side get that little quick  deflection of the meter needle then goes slowly back to the left (infinity.)

       forgot to mention, the voltage is about 240 so I ruled out a low voltage problem.

       got any ideas what else could be wrong if the run capacitor change doesn't work? 


  • Empire_2
    Empire_2 Member Posts: 2,343
    Rheen Cond.


         Have you had a chance to ohm out the compressor?  Get yourself a capacitor checker.  they are relatively inexpensive.  I would check running amps if you can get it to run.  Rheems are notorious for winding compromise especially when corroded contactor has been is the system for a while.  Your amp probe will tell what's going on. Other than that, a mege-ohmmeter would be ideal to check each winding.

    Keep us posted.

    Mike T.
  • Techman
    Techman Member Posts: 2,144
    Delay start

    How about a mn# of the comp because the cap mfd doesn't seem quite right.And a amp reading would help a lot.
  • Empire_2
    Empire_2 Member Posts: 2,343

    I think the dang thing must have fixed itself...........lol

    Mike T.
  • don_9
    don_9 Member Posts: 395
    edited September 2012

    I remember many years ago when i worked for a lennox dealer they were installing equipment with non-equalizing txv valves and we would have problem with the compressor trying to start under a load.Of course a hard start kit was the fixed.

    Have any of you guys ever gone to a comp that was cold and w start up and after a few minutes of running it would trip the breaker? That when you know that the insulation on the windings are shot.That is after you spend some time looking for a external short every where else that don't exist.lol

    Once the winding and oil start getting warm the arcing began.

    I hope you all have a great fall and winter me myself i am going back to listening to some James Taylor live while i look at the weights that i was supposed to lift.
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