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AssuredElectrical
AssuredElectrical, Master Electrician
Category: Electrical
Satisfied Customers: 4241
Experience:  Contractor-42+ Years in the ElectricalTrade
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Hey yall, I have a window a/c unit that keeps shutting itself

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Hey ya'll, I have a window a/c unit that keeps shutting itself off completely. LED's on the display and all. breakers are not tripping.
I had moved the unit to another window and a friend hooked up to a 6' extension cord.
After a year, the a/c started shutting off;(it's not in energy saver mode) then restarting about 30 seconds later, and then coming back on. Fan would start, then compressor would kick on; would run fine for 20 minutes or so and do the same thing again. (This usually happens during the hottest part of the day; not at any other time.)
I checked and noticed the extension cord showed signs of arcing at the plugs, or browning, maybe getting hot.
I had an electrician extend my 220 line six feet. he used what he called a block. Put in a box ran a new pipe to another box where he mounted the female plug. so I'm assuming it was done correctly.
That's when I called LG. cause now I think it's all in the a/c. LG sent people out 4 times to fix it, Replaced the electical parts completely> 4 times. each time the 3 different techs said that this brain; as he called it, was the only thing that could cause it to shut off. And it still does it.
LG gave up, and said if I got an electrician to certify my wiring is ok; they would give me a refund. The money to pay for this is on me.
When the electician was here he checked in the breaker box, said size was proper. (I had turned off the power each time for the a/c techs.)

sorry to be so long winded. My question is:
Could it be a stuck breaker or a loose wire at the breaker?? elecrician didn' take the cover off at the breaker box.

I also noticed when he put the wires in the block. the wire was to thick to fit in so, he removed some of the stranding,

Could that be a problem?

thanks for your time. took this 70 year old a while to try to phrase all this. Hope you can help.

AssuredElectrical :

Welcome. My name is XXXXX XXXXX would be glad to assist.

AssuredElectrical :

I have read the posting, and that can certainly be frustrating, having them out so many times and still not right on operation.

AssuredElectrical :

What exactly is this "block" you are referencing? One thing for sure, you never cut and remove strands on a wire. The wire size is what it is and must be used entirely. Removing strands to make them fit is not allowed

AssuredElectrical :

Not to say it is or isn't creating a problem, it is just not allowed.

AssuredElectrical :

If the AC starts and shuts down as you described, can you restart it again? What is the sequence to restart? Unplug and replug?

AssuredElectrical :

Turn it off with the selector and restart?

AssuredElectrical :

What size breaker is the AC on at the panel? Is the AC, the only thing on that breaker?

AssuredElectrical :

Let me know some of the info and we can continue, thanks.

AssuredElectrical :

Just reply.

Customer:

I stated "then restarting about 30 seconds later, and then coming back on. Fan would start, then compressor would kick on; would run fine for 20 minutes or so and do the same thing again. (This usually happens during the hottest part of the day; not at any other time.) This by itself. no unpluging.

Customer:

the electrician called it a block, it's how he attached the wires together. not wire nuts. metal with set screws in it. then taped inside the box he installed.

Customer:

block is what the electrician called it. metal bracket kind of thing. wires go in a holes at each end then a set screw. he did remove strands. the a/c starts again by itself no unpluging or anything. cant turn it off when it's not on. cant turn it on when it's off. breaker is double 40. wire is 6 gage. a 110 wire also 6 gage runs off of one side to a utility room 10 feet away and connects to washing machine and lighting.

Customer:

i want to remove window unit and install a mini split system. but i need to know wiring is ok.

Customer:

a/c man would install system, but i want to make sure the electrical system is right.

AssuredElectrical :

40 amp breaker and #6 wire is very large for a window AC unit. That size is what normally operates a central ac unit for a 2000 sqft home. So it is large enough for a mini splt.

AssuredElectrical :

I would have concerns over any other 120 volt that is being fed from this line. The breaker will not trip before the 120 volt wiring would burn and melt. There should not be any 120 off of the 240 volt wiring without its own breaker.

Customer:

how do i make sure this shut off thing isnt electrical. hate to put new unit in then have it shut off too.

Customer:

guess i need to just call an electrician other than the one who came out. why wouldn't he have told me that? any other suggestions.?

AssuredElectrical :

The unit sounds like it is shutting down on high pressure or the internal controls. from the sequence. If the problem were in the electrical from the house, it would not stop/restart and operate the same way each time. It would be more random when there is aloose connection on the wiring/breaker.

AssuredElectrical :

I do not know why they would drop 120 line from the ac wiring, it is not allowed. The 120 volt in the home is #12 wire at the largest and only rated for 20 amps. That is the most allowed, 20 amp breakers for any lights and receptacles in the home.

Customer:

guess i'll bite the bullit and call a new electrician

AssuredElectrical :

Your #6 is great on the 40 amp breaker, it is actually rated for 50 amps, so that is a plus.

Customer:

ok thanks

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