Trying to find a replacement relay for a 220v window ac unit.

Discussion in 'General Electronics Chat' started by Stainless, Jul 18, 2014.

  1. Stainless

    Thread Starter New Member

    Jul 18, 2014
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    Hey guys.. I've got an ac that the compressor relay is hanging up on. I got the relay out and am trying to locate a replacement. It seems like everything I find that matches this one.. comes out of China. I don't know enough about this stuff to match one up and I don't want to buy replacements only to find out they won't work when they show up. I checked around town and that's a no deal.

    Can anyone help me in locating this in the states or a replacement that will fit back in the circuit board?
     
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    If it were me I'd try to find a relay with greater current-handling ability. The present one was clearly stressed :(. But I'd think you could source an equivalent in the US. Have you done a parametric search on the web-sites of major manufacturers/stockists?
     
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  3. snav

    Active Member

    Aug 1, 2011
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  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I think the original is a D.P.?
    The link is to a SPDT.
    I would also not only look at a higher rating, but if there is room, fit one off board.
    From personal experience, the PCCT type relays do not have the suitable capacity for the loads they are switching, also it is easier to replace in the future.
    Looking at the Omron G4A sheet, it looks like it could be a sub?
    Max.
     
    Last edited: Jul 18, 2014
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  5. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    original is SPST 12V coil

    Omron part number is G4A-1A-E-DC12
    available at all electronic suppliers.. mouser link here
    http://www.mouser.com/ProductDetail...GAEpiMZZMtSzCF3XBhmW15747hehDm95WUT%2bH7VO8Y=

    No need to find a stronger one.. Omrons don't fail :)
    We use thousands of relays a week and NEVER had an Omron fail in 10+ years..
    Recently switched to Hasco Relays and get a .1% failure rate or so..

    oh and I'd stay away from that Ebay link too.. I'd bet it is fake.. Ormon is knocked off ALL the time.. Buy from a company like Mouser,etc.. thats got a strict counterfeit policy..
     
    Last edited: Jul 18, 2014
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  6. snav

    Active Member

    Aug 1, 2011
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    Third pic from OP shows SPNO on base diagram, Assuming tabs and PC pins are common tie points. I know, never assume, Should meter those.

    I agree, knockoffs are real problem. Motor caps are horrendous these days.
     
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  7. Stainless

    Thread Starter New Member

    Jul 18, 2014
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    Thanks guys. I'm kind of a do it yourself around the house but this is out of my league. I don't have any background in electronics repair and I wouldn't have known where to look to find this part.

    I ordered the one that mcgyvr listed.. I'll update once it shows and is installed. Hopefully that is my problem with the ac unit.
     
  8. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Just a FYI.. another common problem with AC unit motors/compressors is the capacitor..
    Typically if it doesn't start on its own (just sitting there buzzing/humming) and needs a "hand spin" to get started its just the capacitor..
     
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  9. Stainless

    Thread Starter New Member

    Jul 18, 2014
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    The problem with this ac is that when I turn the power off, the compressor still runs. The only way to turn it off was to unplug the unit. I tapped the relay in question and it went off. I thought to myself that maybe this wouldn't be an issue since the ac had been sitting unused since last year and things tend to get stuck in place while sitting. I tried to run it again and it did the same thing. This time, I couldn't get the relay to open back up.. whether it be unplugging the unit or tapping on the relay. I'm pretty certain that this part is the problem.

    The sad thing is.. this ac was purchased brand new and was only used a few months last summer. That's pretty bad since it cost $550.
     
  10. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I just repaired a card from a stove for a friend, the replacement cost was quoted as $200.00, it turned out to be a fairly wimpy PCCT control relay, I just upped the capacity and modified the board to take the new one so it may last a bit longer.
    They are made for economy and compactness!
    Max.
     
  11. inwo

    Well-Known Member

    Nov 7, 2013
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    Good chance that it's the relay. It could also be a leaky driver circuit.

    Check coil voltage when off. It should drop to near zero.
     
  12. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Sticky contacts. Sometimes caused by a cap going open circuit if there is a motor cap.
     
  13. Stainless

    Thread Starter New Member

    Jul 18, 2014
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    Well.. I screwed it up good now. I replaced the relay and was testing the ac out. The compressor came on when I powered it up but then it wouldn't come on after that. Before replacing this relay.. the problem was that I couldn't get the compressor to go off with out unplugging it.

    I wasn't getting 12v to the relay so I got the "bright" idea to use a 12v power supply to manually engage the relay. It was working fine until my jumper slipped off of the prong and shorted out on the board.

    Can this possibly be filled with solder to fix it? I found a replacement board on the net for 50 bucks but am hesitant to buy it because I don't know if something else may be wrong too. I'm assuming the little transformer converts 110v to 12v for the board?
     
  14. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Wow what type of "12v" were you using?? A car battery? :eek:

    The PCB can be repaired easy enough, assuming you didn't kill any components.

    We really need a better (closeup) photo though, under very bright light. :)

    And photos of both sides of the full PCB will help a lot too.
     
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