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-   -   So I want to replace the contactor in my outside unit (http://www.diychatroom.com/f17/so-i-want-replace-contactor-my-outside-unit-151590/)

sarahWW 07-26-2012 09:37 AM

So I want to replace the contactor in my outside unit
 
I ordered a replacement contactor for about 20 bucks. The new part was the same manufacturer, but was the suggested "replacement" for the original part (which was a Honeywell R8242A 1271). The part that arrived is not the same though. It's a "mirror twin". So obviously I can't just swap out the wires one by one and be done.

What is the best way to manage the new wiring? Should I install the new contactor upside down so that all the wires reach? Attempt to drag wires to the opposite side of their former positon? Try to find old stock of the part?

Here is the new part

I will try to attach a pic of the old one, still wired up: (well shoot, it wont let me upload a file) Since I cant do that, just imagine the one above in mirror image.

scottmcd9999 07-26-2012 10:37 AM

First: Why do you want to replace your contactor? They don't typically wear out ...

Yes, you can just turn the contactor upside down. They are not position sensitive.

sarahWW 07-26-2012 11:30 AM

I want to replace the contractor, because the contacts are burned on one side, and when the condenser gets the signal to turn on, the contractor rapidly opens and closes; rather "chatters" - Ka thunk Ka thunk Ka thunks Ka thunk.

biggles 07-26-2012 11:56 AM

might of been a weak coil or the 24V out from the furnace/stat.don't know what a mirror twin is?the one you show is a single pole contactor can't get any smaller.shut the disconnect off mount the wires exactly one at a time NOTE T side is load fan/comp...L side is disconnect into the contact...all the wires connected mount the contactor in the middle of the wires so none pull from either side...do the line wires first both sides...then the 24V pair

ben's plumbing 07-26-2012 12:45 PM

Quote:

Originally Posted by sarahWW (Post 974765)
I want to replace the contractor, because the contacts are burned on one side, and when the condenser gets the signal to turn on, the contractor rapidly opens and closes; rather "chatters" - Ka thunk Ka thunk Ka thunks Ka thunk.

you could try filing it down 1st....shut off power to unit and file down burnt contact as good as you can then try it..worked for me many times....:yes:

sarahWW 07-26-2012 12:50 PM

The link above, in my top post, is to a picture of the replacement contactor on the vendor's page.

I am trying again to attach a photo of the current (0ld) contactor as it was wired into my unit, but the pic is too big. I have to tweak it, will be back in a few

sarahWW 07-26-2012 12:54 PM

1 Attachment(s)
Here is a pic of the old contactor, with all the old connections.

scottmcd9999 07-26-2012 01:00 PM

That's not a mirror twin, it's an exact replacement. It mounts the same way, has the same terminal layout, and should cross over exactly. Don't be concerned with the terminal "designations" - i.e. the L and T designations - just match up the contactor in the same orientation as the original and swap it wire for wire.

I too have fixed some contactors by removing the contacts and filing them down, but it's tricky to do (that #$@% little spring is tough to catch sometimes) - and for 20 bucks it's not worth the hassle!

sarahWW 07-26-2012 01:05 PM

At the vendors page, you can see the part I bought to replace it, per the site's recommendation that this one is a replacement for the one in my unit. All the wiring on the left side of the image of my original contactor, would have to be hooked up to the right side of the new part, if the contactors are oriented the same way. My plan was to get an identical part, and reproduce the positions of the wires exactly.

I can't read electrical diagrams in a way that would help me place the wires, but can only copy what was there before. Which is the "T" side? In my picture of my old contactor, I am guessing it is the right side of the picture, and The black and red are the 24v pair.

sarahWW 07-26-2012 01:08 PM

Scott, pardon my confusion, but on the old contactor, the two screws with little plates that hold down the black and red wires, and have screws of a different color are on the left side of the picture. If I orient the new contactor the same way, the two screws with little plates that are a different color would be on the right. They don't match in appearance, but if I held the old one up to a mirror it would look the same as the new one.

Are you saying it doesn't matter which side has the coppery looking screws with the little plates?

scottmcd9999 07-26-2012 01:14 PM

Quote:

All the wiring on the left side of the image of my original contactor, would have to be hooked up to the right side of the new part
No, you shouldn't do that. The terminal designations on the contactor are meaningless (the original contactor looks to have OEM markings on it, which would not be reproduced on the Honeywell version).

Looking at your two images, with the terminals from the OLD contactor noted first:

11 >> T1
12??) >> L1
23 (L) >> T2
23 (R) >> L2

I can't really read the number on the original image, on the top right side, so just assume it said 12.

scottmcd9999 07-26-2012 01:15 PM

Quote:

Are you saying it doesn't matter which side has the coppery looking screws with the little plates?
Yes, exactly - and in fact, you can swap the those hold-down plates to either end. Just back them out (the screw and all) and swap them with the screws on the other end.

sarahWW 07-26-2012 02:59 PM

Hurray! Since I was relying on copying the placement of the wires and everything looking exactly the same, I did not want to take chances with the swap. Thank you for cluing me in.

Biggles, I was wondering if the transformer might be the root of my troubles. FWIW the AC in my house is in the attic, the boiler for my hot-water baseboard heat in the basement. The thermostat, however is wired so that it controls both cooling and heating, and allows me to run the continuous fan in the attic air handler in either mode.

turnermech 07-26-2012 03:20 PM

Quote:

Originally Posted by sarahWW (Post 974904)
Hurray! Since I was relying on copying the placement of the wires and everything looking exactly the same, I did not want to take chances with the swap. Thank you for cluing me in.

Biggles, I was wondering if the transformer might be the root of my troubles. FWIW the AC in my house is in the attic, the boiler for my hot-water baseboard heat in the basement. The thermostat, however is wired so that it controls both cooling and heating, and allows me to run the continuous fan in the attic air handler in either mode.

your tstat uses isolated subase with a RC and RH terminals. This is the norm for your application. Fan control will come from the RC which is cooling transfromer in either mode (heating or cooling)

Yoyizit 07-26-2012 03:24 PM

Quote:

Originally Posted by sarahWW (Post 974765)
the contractor rapidly opens and closes

This oscillation almost certainly is caused by a high resistance (say, 0.1 ohm) at the contacts or in the supply lines or in the ground wiring for the controls.
The high line resistance could have caused the burned contacts but not the other way around.
Good luck.


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