AC Tuneup questions

[Russianwolf]

Okay, So I called a couple places to find out how much a AC checkup will cost. I'm getting told $75 flat or $60/hr just for checking it, not to mention if something needs to be done. So I go and do alittle looking. Seems that the only thing that you can't do yourself in 5 minutes is checking the freon level.


So does someone know if we can check the freon ourselves without paying excessive prices? I'm fairly sure I will need to have some added, as those couple hot days last week were straining our unit.

The other things listed were:

Cleaning coils on the evaporator
Changing filters
Checking draw on the compressor

[skruffy]

You need a manifold gauge set and hoses to check the refrigerant pressure, and that's going to cost you more than $75. Considering the time to drive to your house, the cost of equipment and the cost of training, I think the price you got is reasonable. And since you think you need work anyway, I'd imagine that the $60/hr comes into play and the actual cost of the check is very little.

[WayneJ]

A real quick check that you can do is look at the sight glass.Its an eye in one of the lines going to the compressor that you can watch the freon in the line. If its clear fluid going by with a couple of bubbles its o.k. If you see foam it means you need freon. If you don't see any circulation, thats a whole other ball game. One of the lines should be hot and one cold
going to the compressor.
Wayne

[Russianwolf]

A real quick check that you can do is look at the sight glass.Its an eye in one of the lines going to the compressor that you can watch the freon in the line. If its clear fluid going by with a couple of bubbles its o.k. If you see foam it means you need freon. If you don't see any circulation, thats a whole other ball game. One of the lines should be hot and one cold
going to the compressor.
Wayne

They put sight glasses on house AC units? I knew they had them in cars, but not houses.

[WayneJ]

You won't find them on a window unit . Central air yes, they would have one close to the compressor,
Wayne

[Hellrazor]

I'll tell you what the recommendation a friend of mine gives. If one line is cold and the other is warm/hot and the AC is working, its fine. Before anyone has a fit, he is a HVAC tech for Honeywell.

[LCHIEN]

Another way is to check the air blowing from your vents.
If its running sixtysome degrees you're OK. Should be some relative amount compared to the air intakes (return air vent).
Those handheld infrared themometers work great for that. I just point them at the plastic or metal vent - they should pretty much be at the temp of the air blowing thru.
I think you can also tell by checking the air temp coming off the compressor. - some differential over ambient.

I notice HF has a non-contact IR thermometer now for $40. Love mine.

[Russianwolf]

okay, condensor assembly is outside. Everything else is in the attic. Any tests I can run without crawling in the attic. I'll keep the vent temp in mind, I don't have a temp guage right now, but I can buy one.

Just checked. It seems to have one 1 inch copper pipe running to the attic. It is insulated and cool to the touch, fairly cold in some thin spots. Didn't notice any ice on the pipes once in the condenser so it isn't frozen up (had that happen before).

[Hellrazor]

Constant freezing of the coils can be a sign the system is low and needs to be rechaged.