PDA

View Full Version : Air Conditioner Advice



Wes Bischel
09-07-2006, 11:22 PM
OK, early this season I fired up the AC only to have it freeze up. The technician came out checked things out and topped off the freon. He said it wasn't worth it to trace any leak(s) until the unit needs to be recharged a few times a year. Well, I've noticed the unit has been staying on longer and longer, and tonight - frozen solid.
The AC is 11 years old and has performed fine until last year and this year when each time it needed a few pounds of freon.

Question - is it worth the $4-600 (the tech's numbers) to trace the leak and repair it? Or would it be better to bite the bullet and replace it? Naturally I figure we'll wait until next spring - early spring. (heat is hot water baseboard)

Any thoughts and/or things to consider would be appretiated.

Thanks, Wes

Mark Rios
09-07-2006, 11:26 PM
Wes, we obviously live in different climates but over here to me, those numbers would be in the buy a new one range. You will get a MUCH more efficient machine and you won't have the maintenance costs either. If you would like an environmental note, a new machine means that you won't be releasing all the freon into the atmosphere.

Just my thoughts.

Lee DeRaud
09-07-2006, 11:41 PM
I agree with Mark, with the addition that you need to find a competent A/C technician before you make your decision. If it's leaking coolant within the compressor, it needs to be replaced now. But if the leak is elsewhere, replacing the compressor won't fix it. Get it diagnosed properly first.

Wes Bischel
09-08-2006, 8:51 AM
Great points guys, thanks. Mark, the environmental aspect really bothered me, and honestly surprised me considering all the efforts that go into recovery etc. As far as the costs, it sounds like gambling - could be a leaking o-ring, could be a bad coil. One will be cheap, the other half the cost of a brand new system.:rolleyes:
Lee, I was assuming (a dangerous thing I do) that both the compressor and air handling unit would be replaced - as well as the lines. Since the AC is stand alone and seperate system from the heat (hot water). Is this assumption wrong?

Thanks again for your help,

Wes

Al Willits
09-08-2006, 8:59 AM
I'm assuming you meant leaking from the commpressor, not within.

If this thing is leaking several pounds each year it shouldn't be all that difficult to find, even a basic freon detector from like Texas instruments should be able to find it, much less the high buck 110 volt detectors

The repairs can be expensive, depending on where the leak is coming from.
Go to your local supplier and buy a bottle of AC leak detection soap and check all the fittings/solder joints ya can, service ports are a good source of leaks, the caps should have o-rings in them to help seal.

Do the checking on the suction side (large copper tubing) with the system off and probably with the system on for the high side, if the system is up to charge, the pressures will be higher, makes finding the leak easier sometimes.

Also ask the tech for hourly charges and maybe ok a hours worth of searching, in most cases if he can't find a leak that is that bad, he's not looking...
2# in a year is a BIG leak in the AC world.

I wonder if you can rent a electronic leak detector ???

Al

Lee DeRaud
09-08-2006, 11:14 AM
Lee, I was assuming (a dangerous thing I do) that both the compressor and air handling unit would be replaced - as well as the lines. Since the AC is stand alone and seperate system from the heat (hot water). Is this assumption wrong?Not necessarily, depending on the construction of your house. If the lines are embedded in the walls (as is typical here), they don't replace them unless they really have to: it really jacks up the cost. New homes typically have a line set preinstalled, regardless of whether the house comes with A/C standard or not.

I also tend to think of the compressor and air handler as a unit, but I've seen many instances where just one or the other was replaced.

Joe Pelonio
09-08-2006, 11:21 AM
Remember that the tech's $4-600 is more likely than not to be at the high end or more. Last time the one here at the shop went out for the same reason, they quoted me $300 and it was well over $400. I'll also mention that something happens every year on this system which is about 20 years old. Unfortunately for me the lease says I have to pay for repairs.
The techs have recommended replacement but I'm sure not going to pay for a new A/C unit for someone else. Yours is not that old yet but as Mark said they have become more efficient so you'll save in the longrun.

Al Willits
09-08-2006, 12:32 PM
btw, its freon 12 that is worst, 22 isn't quite as harmful.
Also most units installed now are R410a and you don't want to use the original line set if at all possible, 22 and 410a freon and the oils used with them are not compatible, afaik

I'd go price one of the new systems before I'd write the old one off, they ain't cheap, and 410a is not environmentally friendly either.


Another thought is what are they charging you to just come and recharge the unit?
Might be cheap enough to just have that done each year, as of now, the epa allows residential units a certain amount of leakage before repairs have to be made, and 2# each year isn't even close.

Once again, your state may be different.

Personally I'd still have someone spend a hour and find out what is leaking, then go from there, if ya don't trust your tech try another company.

Al

Lee DeRaud
09-08-2006, 2:35 PM
Also most units installed now are R410a and you don't want to use the original line set if at all possible, 22 and 410a freon and the oils used with them are not compatible, afaikWhen I replaced my 26-year-old system in 2002, they power-purged and pressure-tested the lines after they removed the old unit. Those were both sign-off items on the inspection.

Wes Bischel
09-08-2006, 9:24 PM
Thanks for the info everyone.
Al, I didn't even think of the detection soap. I have some we used for the gas lines - would that work? Or is it a specific fluid? Gee, maybe I should ask the neighbor behind us if he can get ahold of the detection equipment - I forgot he works for a HVAC company!:o The tech that came said they use an ultraviolet dye that is put into the system to detect leaks. Also, all the HVAC companies in our area charge at least $80 to pull into the driveway.:rolleyes: :( I'll see what my neighbor says about the cost of new units around here. I do know the techs need to have a license to charge the system (even he can't do it for his own home). When they were out this spring it cost us $180 - wouldn't take too many visits to cover the cost of a new unit.
Lee, our place is over 50 years old (brick and stone Cape Cod) - the AC lines run from the compressor inside a downspout (for protection and disguise;) ) into the eaves - the air handler is in a knee wall area. Replacing the lines is relatively easy - it's getting the air handler etc. in behind the knee wall. I have to remove the ceiling of the kitchen porch - thankfully when it was replaced previously, I designed the whole thing so it would come apart kinda-sorta easily.:rolleyes:
Joe, good point about the offhand estimate - bummer about the lease.
Thanks again, thankfully I've got some time to do my homework.
Wes

Jim Bell
09-09-2006, 12:49 AM
Check your schraser valve caps. There should be 2 of them at the point where the a/c is charged. There may also be one on a drier. If they are plastic and after a few yrs fail. Get the metal replacements with "O" rings. They screw right on just like the cap for the air valve on your car tires. After 15 yrs of a/c service work here in Fl I found doing as I suggest will work over 90% of the time. I had a leak detector. After three or 4 leak calls I threw it in a nearby lake. If you find an area that is oily (on the refrigerant lines) that is where the leak is. Hope this helps,
Jim

Bill Turpin
09-09-2006, 1:01 AM
Freon and refrigeration oil(in the crankcase) both will dissolve the other, just like water and alcohol. There is no attempt to separate them in the compressor. There are no piston rings. If you have a 2# leak, there should be a visible oil slick at the leak, which will attract dust and look dark on the tubing. The oil is pumped thru the system with the freon. Most ref techs weigh the freon added with the swag method. There are about 45 billable pounds in a 30# cylinder. They are not going to sell themselves short. Many techs would rather sell you return trips than fix it right the first time.

Find the leak yourself. Look for the slick, zero in with soap bubbles, household detergent works fine. Have the system off, so that the low side will have positive pressure. Wipe off all the soap off when done. The dehydrated soap will look like an oil slick in the future. Your labor to find the leak should save a lot of money. Check all the access valves first, then the large nuts on the line sets. Line sets are notorious for leaks. Next any field solder joints, then the factory welds on the coil and the outside unit. Check for concrete rubs where tubing goes thru walls. Look for oil on the inside of tubing insulation. Check for dirty spots in the middle of outside coil, where a rock from lawn mower may have hit.

Do not let tech use dye, it is actually a contaminant. Lazy techs, who will not invest in an electronic detector, use it.

I have worked residential, industrial, and institutional refrig and HVAC since 1967 in four different states. Unfortunately 85% of the techs are UNDER-SKILLED and/or UNDER-EDUCATED! Then you have to find an honest person in the remaining 15%. Good luck. I have concentrated in ceramic kiln control for seven years, so I can't quote current prices. Your prices sound high though.

Bill Turpin in WNC mountains
NC Refrigeration License #2821

Al Willits
09-09-2006, 9:57 AM
Wes, reason I suggested the A/C leak soap is one, its made for A/C and mostly because they come with a little dauber (sp?) that makes using easier.
I've had great luck with the battery powered leak detectors, just need a bit of patience and no wind, the 110volt I used was nice, but a pain.

If this thing leaks two pounds a year, the tech doesn't need dye to find it, just a little effort, biggest problem we've seen with the dye is if a customer has three calls on his AC and nobodies paying attention, you can flood a system with dye, very slow leaker's are what I'd use dye on, and only as a last resort.

btw while your checking the service ports I'd pick up a valve stem cover off a bike, one that has the end that you can tighten the shrader valve with, check for leaks at the valve opening too.
If the shrader valve leaks, there is a tool to replace the inner valve while under pressure fwiw.

Sounds like your tech is a bit pricey, we get $85 for the first half hour and $80 a hour after that.
If your neighbor has some of the equipt, see if he'll come over for a few bucks, kinda depends on how neighbors you two are.. :)

Lots of info here, pick out what will work for you and have fun...:)

Al