OT need advice: shop ac possible contactor welded 'on'

230v 24k btu frigidaire window unit.
only about 3 years old.
my understanding of these units, having been through three of them in ten years..
is that they really aren't 'servicable'
(i know, should've just bought a mini split)

seems like a welded shut contactor or possible bad relay as board controls will not turn compressor off. literally have to flip the 220 breaker.
otherwise all board controls work, fan speed controls, power saving mode, etc.
my question is how quickly am i gonna burn this thing up just running it as is; powering on/off via breaker with compressor always on while running.

i dont give a care if it dies in a few months, i'll work on a replacement this fall when they go on sale.. but the next few months in the southeast are BRUTAL and i'm insanely heat intolerant.

i could theoretically turn the breaker off every now and again throughout the day, to give it a break and not freeze up. then of course turn it off at night, like i always have.

so what say you brilliant minds of PM.. is this a dumb idea?

just taking this thing out of the window requires moving a mill and surface grinder so i'm just trying to get back to making chips asap.

thanks gang


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It is insanely hot in central Virginia these days. We ordered these to try to make everyone a little more comfortable. Oddly enough, it doesn't seem to be working out.

If the controls don't work you might get away with interrupting power but breakers aren't meant to be used frequently as switches. The main thing is to allow enough time after running for pressure to "bleed down" before reapplying power. You absolutely don't want to power up a motor into a pressurized system. The effect is like a locked rotor. All A/C systems have a lockout function to prevent powering up under pressure and if the controls aren't working you need to allow sufficient time.

It shouldn't freeze up unless you restrict the air over the indoor coils and they work better the less they cycle, when sizing a heat pump you round down in size not up. If a new relay is too much to try then it sounds like you should just run it till it dies considering how much work is involved in replacing it. I say turn it on when you need it and run it till it gets too cold or it's the end of the day.

I know mini splits are all the rage but a 1 or 1-1/2 ton heat pump is about the same price but runs on 240 so less amperage draw.

I have 3 32K window units that we turn on and off with the breakers, and once started they run continuously until we shut them off at night, the thermostats never open. They don't freeze up unless I leave them on overnight and the outside temp gets low. I think you'll be fine.

You could install a remote thermostat to run a relay that supplies power to the ac unit. Put a "delay on" feature so it will take 5+ minutes until it switches on the power. that way it will not start under load.
Bill D

Mud said:

I have 3 32K window units that we turn on and off with the breakers, and once started they run continuously until we shut them off at night, the thermostats never open. They don't freeze up unless I leave them on overnight and the outside temp gets low. I think you'll be fine.

Click to expand...

any particular reason why you use breakers as on/off or are you just in the same boat as me?


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Vanguard...I don't think it is a good idea to use the breaker as an on off switch. I have no personal experience with this but I have heard/read that you can "wear out" a breaker by using it as an on off switch. It kind of makes sense because there is a spring action going on in the breaker and perhaps the spring wears out and causes the breaker to trip when it shouldn't. Maybe someone else has some practical knowledge on that. Perhaps you could use a line voltage thermostat to control the power to the AC and just turn it down at night. I have some of those sprinkled here and there (greenhouse, attic fan etc.) and they work quite well.

vanguard machine said:

any particular reason why you use breakers as on/off or are you just in the same boat as me?


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Click to expand...

Yes, they are too high to reach. I know it's a bad idea, but sometimes you gotta do it. I'm working on one right now, the fan motor bearings wore enough to let the armature rub in the fields. Needed a Big Joe lift and 2 stepladders to get it out. The other 2 go in from outside, they'd be easier. There's no contactor in this one, just a mechanical switch, I'm considering hotwiring it if the switch gives trouble. Looked for new 32K window units, they seem hard to find, fedders doesn't make these any more.

I used to do maintenance for a friend who ran an auction house. He would get good deals on big used window ACs, I would mount them through the wall and bypass the thermostats. Auction day they were all turned on at 8 AM and ran wide assed open until 10 - 11 PM. North Carolina in summer, tin tobacco barn with minimal insulation, 200 people inside.

They ran for years and years.

Paul

Mud said:

Yes, they are too high to reach. I know it's a bad idea, but sometimes you gotta do it. I'm working on one right now, the fan motor bearings wore enough to let the armature rub in the fields. Needed a Big Joe lift and 2 stepladders to get it out. The other 2 go in from outside, they'd be easier. There's no contactor in this one, just a mechanical switch, I'm considering hotwiring it if the switch gives trouble. Looked for new 32K window units, they seem hard to find, fedders doesn't make these any more.

Click to expand...

yeah, didn't even know they existed. i've only ever had the 24k ones.


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crossthread said:

Vanguard...I don't think it is a good idea to use the breaker as an on off switch. I have no personal experience with this but I have heard/read that you can "wear out" a breaker by using it as an on off switch. It kind of makes sense because there is a spring action going on in the breaker and perhaps the spring wears out and causes the breaker to trip when it shouldn't. Maybe someone else has some practical knowledge on that. Perhaps you could use a line voltage thermostat to control the power to the AC and just turn it down at night. I have some of those sprinkled here and there (greenhouse, attic fan etc.) and they work quite well.

Click to expand...

i hear you but 1) buy new ac unit (that i can't even afford right now) move 10k lbs of machines and replace or service the unit or 2) worst case replace a panel breaker that i have plenty of extras of.
probably not the safest option but i gotta do what i gotta do right now to just get through this awful year


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I understand completely. I would do the same thing. Sounds like a heck of a lot easier to change the breaker if it should wear out then the alternative.

If a breaker is switch duty rated (usually for lighting) does that rating also 'count' for loads such as the AC units mentioned? (SWD and HID breakers for example. HID=High Intensity Discharge, I believe.)

Is it merely frequency of use, or are there other qualifications for the rating?

Which Square D or Schneider Electric circuit breakers have SWD (Switch-Duty) ratings?

Get rid of shop dog and get a penguin or polar bear. Other then that enjoy the cool air
Don


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