Question on recharging window a/c unit.

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Mar 10, 2013
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So I found a free 8000 btu window a/c on the side of the road today. It looked fairly new so I grabbed it to see what the issue with it is. The unit was made in 2018 per the sticker. I plugged in the unit and all the functions work fine and the compressor kicks on but the evaporator barely gets cold. Like if the ambient temp is 80 the evaporator may drop to 70. The unit takes r410a which i don't have nor do i want to try and bring to someone to recharge. My suspicion is that the unit is low on refrigerant. I have a manifold gauge set and a vacuum pump. I was thinking of buying one of those low side line piercing valves and trying to recharge the unit myself. I am having trouble finding info on the compatibility of r410a and r134a and if the oils are compatible etc. Maybe the charge is fine and there is an issue with the txv or orifice tube? I understand that r134a and r410a are quite different but the unit was free. Maybe we can pretend we are in the remote jungles of south america and i only have r134a. Is it possible to get the evaporator cold and the pump happy with r134a.
 
They don't operate at the same pressures. R-410a would be expensive to buy for this experiment. Like $70-$90 for a 1.4lb can or so. Plus you would have to find the original leak and fix that.
 
I found a post on reddit about the refrigerant pounds per cubic foot and the r134a is significantly less indicating that the r410a pump wouldn't even be big enough for the system to work properly.
 
Do you have an EPA card?

It's illegal to handle 410a if you don't.
It's also illegal to mix freons.
 
I never seen a window unit go low on freon, it's probably worn out. If it's low on refridgerant, toss it out. There's a leak somewhere and putting refridgerant in without out fixing the leak is a band aid fix. Window units are cheap. Buy a newer high seer unit instead of dumping money on that old, low seer unit.
 
I like your experimental nature. I read somewhere (I think on BITOG) that propane can be used as a refrigerant. I think it would be fun to open it up and try diagnosing what caused poor performance and have a crack at repairing it. Maybe a simple cleaning of an expansion valve or orfice tube would do the trick. If you can get to work, think about how fun it would be to try different refrigerants to observe performance changes?

Having grown up in the southwest USA, think Phoenix climate, I really think air conditioning is luxurious in the summer. Even dog houses are air conditioned out there in the summer..
 
These things are as cheap as $125/$150 on clearance at end of season . Do you really want to waste your time on it? Put it back in the trash.
 
Last one that I had that wasn't working I took apart and converted into a vacuum pump for A/C work. Works great for that.

If you do throw it out, save the start/run capacitor!
 
I like your experimental nature. I read somewhere (I think on BITOG) that propane can be used as a refrigerant. I think it would be fun to open it up and try diagnosing what caused poor performance and have a crack at repairing it. Maybe a simple cleaning of an expansion valve or orfice tube would do the trick. If you can get to work, think about how fun it would be to try different refrigerants to observe performance changes?

Having grown up in the southwest USA, think Phoenix climate, I really think air conditioning is luxurious in the summer. Even dog houses are air conditioned out there in the summer..
R-290 is propane
 
It's a 2018 it's hardly old so I don't care about a big faceless corporation getting shafted in return since the guy who bought it got a bad deal. In my best house in mexico I've got a few LG units that all have been going for 13 years straight without issue and I let family and very close friends use it during the year. Even if it was in like new shape I wouldn't return it since I'm satisfied with it lasting so long and I'd buy more. But a 3-4 year old unit I have zero sadness for the corporation. Sure it wasn't me who paid for it but even then I don't care for the corporation. You're not hurting the little guy. People cry for corporations too much when the corporation would take your house and savings if they could legally write their own laws.

Now I'm not scum I won't return used oil at walmart or pull return scams where I put something way cheaper into a box that had a higher price on the receipt but I'd return an identically priced expensive unit that didn't last at all for another. I did that with a mega overpriced kitchenaid microwave that only lasted 19 months and was outside of warranty with no parts were available to fix it while the GE I had before lasted 14 years. I first tried to fix it and buy parts but to no avail. I then returned that junk kitchenaid at best buy and got another. If it breaks again I'll get a GE again, I won't even bother to buy another and swap. I hate junk kitchenaid. The new kitchenaid island range is having issues and the new 6 burner stove is also having issues within the first 3 years after renovating. Spent so much to get shafted. No sadness for bad corporations by me.
 
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Thanks for the input. I already have 5 a/c in the house so i wasnt counting on this free one working nor do i need to buy any. I just thought it would be fun to play with.
 
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