PDA

View Full Version : Window AC evaporator freeze (low charge?)



ziddey
21-07-2007, 03:14 PM
I was referred to this forum for this question. I imagine it's extremely simple for you guys. Basically, I picked up an AC from someone who dropped it out a second story window. The chassis is extremely banged up, and everything is shifted slightly in a different direction. But I managed to work with the electronics and get it started. The unit does work for the most part.

However, the problem I'm having is that the evaporator will eventually freeze over. I noticed it was missing a vital piece of styrofoam, and it was drafting a large amount of outside air, instead of only inside air across the evaporator. I cut up a pizza box and used it to temporarily fill up as much of the gap as I could. That more than doubled my running time before a full on freezeover, but it still happens.

For what it's worth, the outside temp at the time of testing was around 65'f, and room temps were around 75'f. I noticed that after the evap froze, I was still getting a decent amount of airflow (although substantially less). Given the temperatures, I was wondering if it's simply that I haven't isolated the airflow to only come through the evaporator, or would I most likely be low on ***** due to a leak from the drop.

I know very very little about air conditioners, and am intending on giving this ac to a friend once I restore it a little cosmetically.

That said, there's no ***** scent emitted during operation. After creating a makeshift duct, the time for total freezeover was around 15-20 minutes. The elbows started developing a little frost after about 1.5-2 minutes.

I know that inside/outside temps weren't that high during testing, and I'm waiting for it to get hotter to give it more official testing. Also, I'm intending on creating a more proper duct as well, but figure I'd post here and see where it goes.

The unit is 9800btu, if that helps any, given the temperature conditions of the test.

edit: Also, the unit is a whirlpool, using r-22

The Viking
21-07-2007, 03:29 PM
1. Call an A/C engineer.


If you decide against this advice.......

Is the fan(s) working properly and the blades undamaged?
A "window rattler" will not operate well with any type of duct attached, their fans are not designed to cope with the resistance a duct will add.

If the fans are operating, the coils/filters are clean and you sealed all air leaks but you still got the same problem, then see 1 above.

paul_h
21-07-2007, 03:49 PM
If you have a leak, you might see minute traces of oil. Its not a sure thing, but it is usually there. If there is, you'll need someone with full HVAC gear to reclaim, repair and recharge as there's no factory access valve on those things. If it's a leak, then it's usually not worth repairing these things, especially in banged up condition. The cost is close to a new one or more than a second hand working one, and no fridgey would guarantee a system thats been dropped as the compressors don't like that.

If there's no leak, then it could be damage to pipework like kinks and bends caused by the drop, again, you'll need a fridgey to reclaim, replace pipework and re-gass, it's not worth repairing due to cost and there'd be no guarantees on the work. Being a window unit, you could take it to a workshop for repairs which may make it cheap enough to consider, but I wouldn't due to the damage from dropping and missing insulation.

ziddey
21-07-2007, 04:01 PM
Thanks for the posts.

There appears to be no oil residue anywhere.

As for duct, I was using the wrong word. I meant the styrofoam shroud that makes it so the fan draws air from inside the room, through the evaporator, up and out the vents. The critical piece shielding the condenser/outside was missing.

Thanks for confirming that there's no user accessible service valve. I thought my brain was failing.

Here's to hoping that a new shroud would fix things :). Anyone have any ideas for how to create one easily? I'm thinking of using some styrofoam, and that spray foam sealant

paul_h
21-07-2007, 04:25 PM
I dunno, maybe make the shape out of thick cardboard and cover it styrofoam from old tv boxes or with foam (the packing type) or bubble wrap? I'd be raiding my cardboard boxes and other parcel/packaging type things for a quick fix.

Gary
21-07-2007, 04:58 PM
You can get a brand new one at Lowes/Home Depot, et al, for less than $100.00

Lowrider
21-07-2007, 09:51 PM
Perhaps the former owner was fed up with the unit freezing up and tossed it out the window! Perhaps he had the bucks for a new one!?