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-   -   Lennox compressor not coming on (https://www.askmehelpdesk.com/showthread.php?t=645311)

  • Mar 22, 2012, 11:23 AM
    accordy2g
    Lennox compressor not coming on
    I have a lennox model 13hpd 036 230 01, S/N 5807m06629 and today I noticed my unit wasn't blowing cold air. The air handler works but the outside compressor doesn't turn on and the fan doesn't spin. I'm not too knowledgeable in A/C but am handy and would like to see if I can diagnose it before having to pay another 200 for a HVAC to come out. Any help with this. Already check both breakers and spun the fan and it moves rather freely.
  • Mar 22, 2012, 12:23 PM
    thermalmedics
    Could be the dual run capacitor. Is it bulged or leaking?

    How about the contactor can you push the button (plunger) and get it to come on at all?

    If it comes on after pushing the contactor than you are looking at the contactor coil or the 24v going to it from the t-stat.

    If no operation at the contactor than check dual run capacitor and make sure you are getting 240 v to the line side of the contactor.

    These image and videos may help
  • Mar 22, 2012, 04:21 PM
    mygirlsdad77
    Also, in addition to therms great advice, check for tripped breaker or blown disconnect fuses to the condenser. Or more clearly, check for 240 power to unit.
  • Mar 22, 2012, 05:28 PM
    jdublon
    The 1st thing to do is to check if you have power coming to the compressor if you have power then it's the compressor and you need to replace it checking capacitor

    look in this web for answer
  • Mar 22, 2012, 08:03 PM
    mygirlsdad77
    Jd. Welcome to AMHD. Why would you suggest checkiing for power to the compressor when you should really start by checking for power to the complete condenser? Neither the fan or compressor is running, which clearly states that there is no power to the unit, or the contactor is bad, or the dual cap is bad. Heck, it could even be as simple as the contactor is not receiving low voltage to pull the contacts closed. Lots of options here, but to suggest checking for power to the compressor, when nothing at all is happening to the condenser, is not good advice. Sorry man, but there are much better trouble shooting methods. You start at the beginning and go from there. You certainly don't jump straight to the compressor in this particular case.
  • Mar 24, 2012, 06:01 PM
    accordy2g
    Thermalmedics:

    I checked the contactor and pushed it in and the fan and compressor didn't kick on.

    The capacitor didn't have a buldge or leaking anything. Think it may be the capacitor?
  • Mar 24, 2012, 08:08 PM
    thermalmedics
    Ok so we are basically down to two items, voltage to the unit or the run cap. Since we are dealing with the compressor and fan motor together and your check at the contactor revealed neither came on then yes:

    Dual run capacitor (I checked out your specs on line here) or power to the contactor itself.

    If I was there I would eliminate the contactor first. If you have access to a voltmeter you should read 240volts to the bottom or line side of the contactor. This is where voltage comes from your breaker box to the disconnect and then into the unit. If you have 240 at the line side then push the plunger while checking the top of the contactor (right at the bolts) you should also have 240volts. Contactors can fail in all sorts of weird ways. I even saw on with a roach stuck under the plunger and it wouldn't close! If all of this checks out then I would swap out the run capacitor. Inspect wiring as well at the contactor etc while you are there for loose wires/contacts etc. (sometimes it is just that simple)

    If you do not have the 240 at the line side of the contactor than you need to back up to the disconnect box and check fuses for continuity (use the ohmmeter)etc. You can check voltage there as well if you pull the cover off the box. No power at the disconnect than you keep backtracking to the circuit breaker box. Now you are at the source.

    A lot of DIY electrical so just be careful use insulated tools.

    BTW, I have found many run capacitors that look fine but go bad as I'm sure others will attest to on here. Testing them is easy if you have a MFD check on your multimeter but I know not everyone does.


    Please give an update on your progress and findings.
  • Mar 25, 2012, 11:11 AM
    mygirlsdad77
    Great advice thermal!
  • Mar 25, 2012, 03:17 PM
    accordy2g
    OK so I tried it out... Tried to check the wires for 240v and got a big pop and flash of light so not being a genuis I'm assuming I crossed the lines. Scary for me but with that I'm assuming I would have power going to the contactor. When I turn on thermostat the contactor pulls in. Im thinking way over my head huh?? I post pics of my unit.
  • Mar 25, 2012, 03:28 PM
    accordy2g
    http://i97.photobucket.com/albums/l2...g/IMAG0733.jpg

    http://i97.photobucket.com/albums/l2...g/IMAG0732.jpg

    http://i97.photobucket.com/albums/l2...g/IMAG0731.jpg
  • Mar 25, 2012, 04:01 PM
    thermalmedics
    Yikes! About the flash/pop. I guess that would verify the 240 going to the contactor!! Also the t-stat signal to the coil (wires on the side of the contactor) are good, so it is doing its job.

    Check main breaker just in case it flipped during the flash/bang.

    Nice pics by the way, swap out that run cap with exactly the same one. It looks a little swollen on top-hard to tell.

    1.pull power to the unit at the disconnect2. holding the insulated handle of a screwdriver touch each of the terminals of the capacitor (to each other) before even thinking of touching a wire.
    3.mark the wires and/or take photos to verify position (youve got that down)
    4. remove wires and replace with new dual run cap with the exact specs (can almost read it 45/5 mfd and 440 VAC maybe? ).

    5.once it is all hooked up - reset disconnect and test it out at the contactor plunger again.

    Should be good, I am thinking. Anyone else?

    Thanks for the kind words mygirlsdad77 - I'll help out where ever I can and I'm always learning too!
  • Mar 26, 2012, 09:32 AM
    accordy2g
    "1.pull power to the unit at the disconnect2. holding the insulated handle of a screwdriver touch each of the terminals of the capacitor (to each other) before even thinking of touching a wire."


    Im going to order the capacitor online today.
    Now to PRETEND I'm a complete moron when discharging this capacitor: I have cut the disconnect power from the unit since yesterday when it popped :) So the unit will be off for a few days by the time the cap gets delivered. So when the capacitor comes in which screwdriver is OK to use. I have the standard rubber screwdriver but will go and buy an insulated screwdriver.

    Also is there any gloves that I can buy to help. Im hesitant now with shock happening yesterday.

    Also when it does discharge will there be a pop or I won't even know when I have done it right? Just trying to not ti kill myself.

    http://i97.photobucket.com/albums/l2...dy2g/18755.jpg

    http://i97.photobucket.com/albums/l2...1010045Q32.jpg
  • Mar 26, 2012, 09:46 AM
    thermalmedics
    Those are way good for it.

    Hey after a couple of days don't worry about the stored charge in the cap. I mean still discharge it for habit sake but they hold that gnarly charge right after having power applied to them

    Here's a video of me giving the scoop:

    http://www.youtube.com/watch?v=_hnVcfXqjnY

    Last thing: It is just me and I don't pump any product but there are some good and bad caps out there brand wise. There were just a ton of chinese made junk around and a lot have been swapped out.

    I use mars brand made in mexico but that's me.
  • Mar 26, 2012, 03:43 PM
    mygirlsdad77
    Great video. Is that a black mouth cur (the dog)?

    Accord, follow thermals advice. The top of the dual run cap is definitely bulged. Please let us know how it all turns out.
  • Mar 27, 2012, 08:31 AM
    accordy2g
    Thanks ordered the capacitor yesterday should be a few days before it coes in. I get back into town Monday night so Tuesday ill install it. Should I use any rubber gloves or anything when discharging it??

    Will any sparks occur when I touch all three?
  • Mar 27, 2012, 03:13 PM
    thermalmedics
    Quote:

    Originally Posted by mygirlsdad77 View Post
    Great video. Is that a black mouth cur (the dog)?
    .


    Man somebody tell me. I found Hondo under a bush in July 08 in Phx. I think he was a victim of the housing crash and someone mistreated him. Anyway he hit the dog equivalent to powerball and I don't have a clue what is in him but he is a cool dude.


    About the run cap. No more sparks. Just pull out that disconnect, touch the three terminals (so the screwdriver is touching two at once - shorting it to itself) again for good habit.

    Label, photo and pull leads. (about pulling the leads - just like your mom said about pulling the vacuum cleaner out of the socket by the cord - pull the metal fitting - use needle nose pliers if stiff)

    Re attach and put disconnect back in
  • Mar 27, 2012, 03:45 PM
    mygirlsdad77
    [QUOTE=thermalmedics;3067296]man somebody tell me. I found Hondo under a bush in July 08 in Phx. I think he was a victim of the housing crash and someone mistreated him. Anyway he hit the dog equivalent to powerball and I don't have a clue what is in him but he is a cool dude.


    I just got a mix between a black mouth cur and a boxer, and I got to say, it looks an aweful lot like yours. Awesome dog either way.
  • Mar 31, 2012, 02:22 PM
    accordy2g
    Thermal: got it in and a quick five minutes swap and it turned on immediately.
    Thanks so much got the mars brand capacitor and for 17 bucks I fixed it. I really appreciate it.
  • Apr 1, 2012, 08:08 PM
    thermalmedics
    Nice job and you probably learned a ton. Pass it on
  • Apr 3, 2012, 01:15 PM
    accordy2g
    Learned a lot your right!! Thanks again!

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