Noisy contactor - replace?


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Old 05-22-13, 06:39 PM
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Noisy contactor - replace?

I have a Carrier 38XD136300 AC unit. The contactor is really loud. If I push it down a little it's nice and quiet. When it's loud, I don't see it moving, but there has to be some mechanical action causing all that noise. I have 2 of these and they are both doing it.

If this noise is the contacts opening and closing I suspect it's not a good for the rest of the components. I'm assuming it's better to keep things off until this is resolved.

Can this behavior typically be resolved by sanding the contacts with emery paper or am I better off looking for new contactors (I don't want to spend an hour on the existing one just to have the problem come back in a month....)?

If new is better would a local electrical supply house have them - or do I have to go online?

There's no part number on the unit but I've found these descriptions based on the AC unit part number:

* CTR30242PSD: 25 to 30 Amp 2 Pole Contactor 24 Volt Coil Standard Duty
* HN52KD020 2 pole 40Amp, 50 Amp resistive 24 Volt

That carrier part number was associated with a Google search, but I can't verify it actually matches my unit.

Here's a photo of the contactor:
 
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Old 05-22-13, 07:07 PM
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Welcome to the forums.

You can mess with that for hours and it could still hum/buzz.
That contactor looks fairly old.....better to just replace it.

You can use any two pole 30amp 208-240vac 24 vac coil contactor.

The top number you had in your post would work but pretty expensive.

In the link below is just one place that sells several different versions of the same contactor.
Contactors


Electrical supply stores don't carry them. You would need to go to an HVAC supply center.
In NJ I use Universal Supply. They have many branches and will sell to the public
Universal Supply Group, Inc.: Locations
 
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Old 05-22-13, 07:13 PM
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Packard C240A 2 Pole 40 Amp Contactor 24 Volt Coil Contactor: Amazon.com: Industrial & Scientific

I prefer Mars 40 amp 2 pole 24VAC contactors but this one will work...
 
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Old 05-22-13, 07:15 PM
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PJ you are too fast for me
You must type with more than 2 fingers.
 
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Old 05-22-13, 07:50 PM
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Yeah.....I use all three of mine


Good choices on contactors. Always nice to see what the pro's prefer.
 
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Old 05-22-13, 07:56 PM
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Wow that Packard seems a little too good to be true on the price!

I'll try calling around to some local supply houses and see what I can find.

I see the Mars for $15-$25. Is that a price range I should shoot for. What other names should I look for or avoid?
 
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Old 05-22-13, 08:04 PM
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I agree....that Packard does seem a little inexpensive.

I would have said $20-$30 for a price range.

Call over to Universal. They carry good products.
 
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Old 05-22-13, 08:31 PM
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White Rodgers and Honeywell are some good choices.

I usually stock Mars.
I have some Packard capacitors on my shelves. Can't say I've tried their contactors.

12 to 20 bucks online or 50% more in a brick and mortar store would be some good prices.

I avoid Large contactors that might short to the panel unless I need a 50 amp model.
 
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Old 05-23-13, 07:07 AM
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I called a local supply house and they said they had 2 Honeywell for $25 each. So I go down and they can't find any, but it turns out they had the Mars for $17, so that worked out.

Holy cow, HUGE difference between the noisy chatter of the old one and the simple click and then silence with the new one.
 
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Old 05-23-13, 07:10 AM
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A good solid electrical connection is better for the equipment too.
 
 

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