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I recently asked a question about my AC unit not working properly, and I determined it's a faulty contactor.

However, I cannot figure out what replacement contactor to get.

  • The unit is 30 years old, so...

    • I do not have a manual (we just moved here 3 years ago)
    • the specs sticker on the contactor is worn away/gone
    • the company (Ruud/Rheem) has not been helpful

MY QUESTION: How can I determine the correct part?

  • Preferably, a model number or suggested replacement part would be appreciated. If not possible, knowing the specs (current, power, voltage, poles, etc.) would also be helpful -- can I determine any of this otherwise?

    • Note: My assumed knowledge: it's a single-pole 110v (as I can see "110" on the side.

    • Note: I did find Contactor 42-25101-01 on RepairClinic that claims it fits a Rheem RAKA-030JAZ 5339 unit (but Rheem RAKA is different from RUUD UAKA, so I'm assuming this is not necessarily compatible.

Details:

  • AC model: RUUD model# UAKA-030JAZ (serial# 5339 M1495 7649) [mfd: 04/95]

  • Photos of current contactor:

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  • Photo of wiring diagram:

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  • Photo of sticker on pull-out / disconnect box.

    enter image description here

    • are these max specs or the actual specs of my machine (i.e., the specs I could use to order a new part?)
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  • is there a data plate on the compressor?
    – ratchet freak
    Commented Jun 5 at 14:38
  • Most AC stuff is 240V, not 120V, but the picture of the wiring diagram is too small to actually read.
    – Ecnerwal
    Commented Jun 5 at 15:02
  • @ratchetfreak I'll take a look when I get home -- will update once I get a chance. Would that data plate provide adequate/complete info relevant for me, then?
    – theforestecologist
    Commented Jun 5 at 15:22
  • @Ecnerwal yes I know that. I was just going with the 110 on the side of the contactor. I've also edited/updated my post with HQ wiring diagram.
    – theforestecologist
    Commented Jun 5 at 15:25
  • related: diy.stackexchange.com/questions/169970/ac-contactor-1-pole-or-2
    – theforestecologist
    Commented Jun 7 at 5:16

2 Answers 2

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I found a Ruud specification sheet there which includes performance, electrical, and physical data. The electrical data for your model is on the bottom line of the screen shot below. It should be the same information as that shown on the nameplate of the actual unit.

Ruud AC electrical data

Based on this you'll need a contactor with a 24 volt AC coil, two pole, 240 volt, at least 30 amps capacity (eg if for some reason a 40 amp unit were easier to get, that would be fine).

If the one you find isn't an exact match physically that's not a big deal. You can use a few sheet metal screws to hold the new part down in roughly the same area and it's fine.

While you're in there have a look at the capacitor. If you see any signs of oily leakage, or the ends of the cylinder are bulged or domed at all, or it just plain looks old, consider replacing that too. They're cheap.

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  • 1) I don't know how you found this, but well done! (But, how did you find this?)... I just got off a 30min phone call with their manufacturer customer service line (479-648-4900), and they actually just emailed me the same form that you link to. 2) I understand where you got the 30 amps suggestion from, but can you explain how your image led you to know I need the remaining specs you cite ("24 volt AC coil, two pole, 240 volt,")? Thanks!
    – theforestecologist
    Commented Jun 5 at 20:08
  • 1
    @theforestecologist I just searched the bare model number, skipped the results from justanswer, repairclinic, and amazon, and this one jumped out at me. Trained eye, I guess? The rest is mostly experience: a US residential split air con is virtually always 240 volt (which means 2 poles switched) and uses a 24 volt coil. But the sheet does say phase/hertz/volts is 1/60/208-230. Range 208-230 means really we're looking for a 240-volt-rated contactor because that's just how they're offered, and 1-phase 208-230 (or 240) in the US also means 2 hots and no neutral, thus 2 poles.
    – Greg Hill
    Commented Jun 5 at 21:22
  • Even without looking at the spec sheet, I saw 030 in the model number and thought "It's a 30,000 Btu/2.5 ton unit, so 240 volt, 30 amps or less." Then I decided I'd better find an actual source to validate the intuition.
    – Greg Hill
    Commented Jun 5 at 21:27
  • Thanks for all the info. Interestingly, after more than a week of trying, I got a message back from Rheem. They actually suggested the following part: "42-25101-01 PROTECH Contactor - 30A 1-Pole (24V coil)" -- this contradicts your suggestion. Does theirs seem reasonable? (I'm also going to add this as an answer to enable more eyes/comments
    – theforestecologist
    Commented Jun 6 at 22:11
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After more than a week of trying, I got a message back from Rheem. They actually suggested the following part: "42-25101-01 PROTECH Contactor - 30A 1-Pole (24V coil)"

  • This is the same part I had stumbled across online myself (and is linked in my Q)
  • This response from Rheem contradicts Greg Hill's useful answer, in which he suggests I need a two-pole contactor. I'm not sure how to rectify these differences...?
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6
  • The contactor in an AC is not serving as a disconnecting means, only a control means, so it just needs to break the circuit somewhere, not isolate the compressor well enough so that you can poke it without getting zapped
    – ThreePhaseEel
    Commented Jun 7 at 4:15
  • @ThreePhaseEel thanks for the comment -- could you explain how it relates to my post? Are you suggesting the 1-pole or 2-pole is more likely?
    – theforestecologist
    Commented Jun 7 at 4:17
  • I'm saying that the manufacturer only needs it to be a one-pole contactor, at least in your unit. That doesn't mean that a two-pole unit won't work though.
    – ThreePhaseEel
    Commented Jun 7 at 4:18
  • @ThreePhaseEel Ah, got it. any benefit or risk associated with using 2 vs 1?
    – theforestecologist
    Commented Jun 7 at 4:20
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    There's a wiring diagram on the side of the contactor case. It illustrates that this contactor has a switch on one side and is wired straight through on the other side. My mistake: I think of these as 2-pole, and some actually are, but this is a good reminder that others are technically 1 pole because they switch only one side.
    – Greg Hill
    Commented Jun 7 at 20:53

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