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Question on ac cutoff switch

oldpops

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Feb 23, 2018
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303
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Southern California
Hello! We're in the middle of another heat wave here in Southern California - and where I live it's 102 degrees right now as I type this. Anyway, our AC stopped working (2-1/2 ton. Blowing warm air). Went out side and neither the compressor or the fan were working. Checked the AC breaker and it had not been tripped. This has happened before and it turned out to be the run capacitor.

Got a replacement capacitor and turned off the AC breaker at the panel, and then went to out the AC disconnect ( Model #: Cutler Hammer DP222R service disconnect) to pull out the disconnect. It would NOT budge. I could not get the thing to to pull out, no matter how hard I tried. I tried tapping, smacking, wiggling, pushing/pulling, side to side motion, up and down, etc. ) - nothing would make this thing budge. Did some more investigation and found all the condenser coil fins almost completely blocked.

Since the AC breaker at the main panel didn't trip/go off, then my guess is that the capacitor blew when it got too hot, which didn't take long since the ac condenser coils were pretty much completely clogged. Then maybe a backward surge welded the ac cut-off pull out to the contacts inside the box??. **Note: The power still goes through the ac cutoff switch to the compressor - I just can't get the ac cutoff to come out of the box on the wall.

Long story short, #1) we killed the power to the ac at the breaker panel . #2) we thoroughly cleaned the condenser coil and all the fins are clear. #3) I verified no power at the capacitor(several times) then swapped the blown capacitor for a new one, making sure all the connections were tight. I turned the AC breaker back on and turned on the ac in the house on the thermostat. AC comes on and off like it's supposed to!

My guess is that I will need to remove & replace the cut-off switch. Any other suggestions from folks here? As always, thanks in advance for all who offer suggestions and advice!!
 
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rlitman

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Oct 18, 2010
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Long Island
The disconnect should fit tightly enough that it shouldn't experience arcing, since you're not typically disconnecting it under load. My guess is that it corroded badly to get to the point that it could arc and weld. Regardless, it's time to replace it.
 

PoorUB

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Fargo, ND
My guess is that I will need to remove & replace the cut-off switch. Any other suggestions from folks here? As always, thanks in advance for all who offer suggestions and advice!!
Seems like a correct plan to me. Usually those pull out disconnects fry open and you lose power. I don't think I ever saw one fry shut.
 
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oldpops

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Feb 23, 2018
Messages
303
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Southern California
Thanks I saw a video on YouTube where an HVAC guy said he had the same problem (really hard to get the pull out to come out - so he was replacing the whole disconnect box
 

fitter30

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Jun 23, 2019
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Peace Valley,mo
Some condenser coils are double row. Look through the top unit off ( !ight have to pull the top) look at the opposite end of where the piping enters see if there's two rows of coils it there is top has to come all the off coils get split inner coil is dirty only about 70 -80% can be split. By turning cycling power if unit went out on a high pressure safety will reset control might take 5 minutes to start.
 

fitter30

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Peace Valley,mo
With power off the inside cover sometimes can be remove with pull out still in. Spray the pull out with wd40 or penetrating fluid. Can power it back up. Come back the next day try it again. Kill the power try pulling it. Pull to hard might come off the wall. Might try prying off the box itself. Comes out use Dielectric Connector Grease. Can get a little tube auto parts for spark plug boots.
 

brewchief

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Sep 20, 2008
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Michigan
I've seen more then a few disconnects stuck like that, if you pull hard enough you can sometimes get the entire interior plastic to break apart. Replacement of the disconnect is the easy fix. If you really want to make it easy buy the same model and just swap the guts.
 
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oldpops

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Feb 23, 2018
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303
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Southern California
Thanks everyone! I didn't take the top off the condenser this time (I have in the past) because it quite a pain to hold the top up to clean from the inside. The fam wires are so short that there is no way to set the top to the side. I wish they had put a plastic connector of some sort on the fan wires so that the fan wires could be unplugged. This would allow easy access to the inside. Does anyone know here of any kind of easy wiring plug kit to put on the fan wires so that it can easily be disconnected and then the entire top can be removed and set aside. Right now I'm just thinking of using a WAGO connector. Thoughts?
 

rlitman

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I wouldn't use a WAGO exposed to the elements like that. A Deutsch connector should work.

Use the male end (more exposed pins) on the fan side, so it's more finger safe (though removing the fan with the power on isn't all that smart anyway...)
 
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oldpops

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Feb 23, 2018
Messages
303
Location
Southern California
Thanks! I like the idea of being able to disconnect the fan in order to remove the top. Then clean the coils, then reconnect the fan and put the top back on! Do you folks think I should switch to a fused service disconnect switch?
 
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