window ac unit - how cold?

[fishman]

As I was flipping through my tractor manual /forums/images/graemlins/wink.gif in my tiny office in the garage I couldn't help but notice that it was kind of hot. I had started the window unit about an hour earlier, but it still hadn't cooled the place down.

So I whipped out my trusty thermometer and found that the 6000 btu unit was blowing 64 F air into my 180 square foot office with the compressor running. Ambient air temperature was 84 degrees.

Follow up testing revealed that 64 degrees F was as cold as the output would get. So my question is this: Is that as cold as it's supposed to go? Seems to me I've heard temperatures in the 40's as something to shoot for.

The unit was purchased in about 1995 and it's a good one. But like-sized units are selling for around $120 now. Just looking for a little advice here.

 

[Bird]

John, I can't say for sure, but that sounds to me as if it's low on freon. For the air coming out to be 20 degrees cooler than the return air is usually considered "normal", but as that 64 degree air cooled the 84 degree air; i.e., the return air should have been gradually getting cooler, then the output should have been getting cooler also. I don't know about getting down into the 40s, but I sure would expect it to get down into the 50s at least.

 

[BillyP]

I agree with Bird, it does sound like it's a little low on freon. Another thing to check is the condenser coils. If they haven't been cleaned in a while and air is restricted, it could cause this type of problem.

A poor man's way of checking freon is to feel the condenser coils. They should be hot to the touch. Then check the evaporator coil. They should be sweating. If you have a very low humidity climate, it won't be sweating much though.

 

[Bird]

</font><font color="blue" class="small">( If they haven't been cleaned in a while and air is restricted, it could cause this type of problem.
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Good point. I've seen that happen, too. One nice thing about a window unit is that you can just slide it out, put in the bed of the pickup and go to a coin operated car wash and do a good job of cleaning it.

 

[fishman]

So, assuming it's low on freon (and I still need to check that out using BillyP's suggestion), would it be a good idea to have it recharged? I guess I'm worried that the cost may be excessive and/or the unit may have sprung a leak. I'm going to check locally re: cost, but any thoughts on that from anyone?

 

[BillyP]

If it's low on freon, you'll have to have it recharged. How much the service will cost verses a new 6,000 BTU AC will be the deciding factor. I'm not sure on this but (I think) by law, if it's low on freon and before they will recharge it, the service person is required to check for freon leaks. That can run into quite a bit of cash.

Of course you can always find a refrigeration guy willing to do a cheap quick fix recharge. The thing is, on these small units, they don't have to lose much to not cool right. It could have a fairly slow leak and after a recharge would last several more years.

 

[fishman]

Well, let's hope it's dirty. A recharge will cost $35, but the ac guy told me basically what you already said: It likely just needs cleaned. He said that 90% of the time that's what it is, and most of the ones that need freon have been damaged. I'm putting it on my project list for the weekend and will report back.

 

[Bird]

It's been 30 years since I had to have one cleaned, but that was all it took to fix it. My brothers do quite a bit of RV air-conditioning work and sometimes have to recharge one, but cleaning is the more frequent repair needed.

 

[fishman]

Oh, and Bird, the ac guy also said the same thing you did: The car wash is the place to clean it. Just don't spray any of the fins at an angle and let it dry completely before using.

So although new units are rediculously cheap and have a nifty remote, I'm feeling a lot better about spending $1 and cleaning the one I have. /forums/images/graemlins/smirk.gif

 

[BillyP]

fisherman, Even if it does need a recharge and the unit is still in good working order, I'd be willing to pay 35 bucks. It's a gamble to how long it will last but it could last several more years. Hopefully it's just a dirty condenser coil.