A/C help

[97sx]

Just had my AC recharged. Took nearly 3 pounds of r12. Seems like a lot to me and not have a leak. The AC test didn't reveal any leaks.

Turned it on. Blows cold briefly then it gets warm.

Where do I turn next?

[Silver Goose]

3# is a lot, if it really took that much, there's a significant leak. How old is this A/C? Did you mean to say R12? Are you asking about a rooftop trailer A/C or a vehicle A/C? It's been awhile since R12 was available and I think it was primarily used in automotive A/C.

In either case, there could be a problem with the expansion valve and that can be diagnosed with gauges.

[mopariac]

Originally Posted by 97sx

Just had my AC recharged. Took nearly 3 pounds of r12. Seems like a lot to me and not have a leak. The AC test didn't reveal any leaks.

Turned it on. Blows cold briefly then it gets warm.

Where do I turn next?

Sounds like it is overfilled and liquid is getting to the compressor. It should be R-22 for RV air. R-12 is for Auto use.

My compressor is a Bay Breeze by Armstrong and if it is completely evacuated, it requires 19 ounces to fully charge it.

What brand AC is it? Hope you can get it fixed...

Tharon

[97sx]

Should have specified. It is for my 84 motorhome. It is the the auto AC not the rooftop unit. I know it is R12 and it has not been converted to the new refrigerant.

Clutch engages and everything seems to be working.

When they recharged it today I was very specific that it needed tested for leaks. They said they did not find any.

This motorhome has sat unused for over 10 years.

[Silver Goose]

I don't know what a full fill on that system would be. I guess they didn't say if it was low or out of freon. If it hadn't been in use that long, you may have lost most through a small otherwise undetectable leak over that period of time. If it was out, they should have replaced the dryer and then pulled a vacuum on it before filling it. How much does a # of R12 go for these days? Maybe I don't really want to know. I didn't think it was legally available anymore.

[97sx]

Originally Posted by YankeeDoodle

I don't know what a full fill on that system would be. I guess they didn't say if it was low or out of freon. If it hadn't been in use that long, you may have lost most through a small otherwise undetectable leak over that period of time. If it was out, they should have replaced the dryer and then pulled a vacuum on it before filling it. How much does a # of R12 go for these days? Maybe I don't really want to know. I didn't think it was legally available anymore.

$70 a pound. It is not easy to find!

[richinny]

some systems had the freon capacity listed on the compressor or on a label under the hood.

[IPM]

Originally Posted by 97sx

Just had my AC recharged. Took nearly 3 pounds of r12. Seems like a lot to me and not have a leak. The AC test didn't reveal any leaks.

Turned it on. Blows cold briefly then it gets warm.

Where do I turn next?

gauges need to go on the high and low sides and diagnose from there.

i've been using envirosafe r12 replacement for nearly a decade now, much much cheaper to use and blows much colder air due to the greater amount of energy required for the phase change.

http://http://autorefrigerants.com/co00033.htm

[Beginner]

I am unfamiliar with the setusp in your motor home however the basics are the same.
1. Get out where you can run and drive at highway speeds for 15 or twenty minutes with the AC on. Pull over, run up front pop the hood and check the accumulator to see if its sweating. If it is sweating and you can touch the accumulator with the engine running and the AC still engaged touch it to see if it feels cold. If not, be standing in front of the vehicle with the hood open and the engine running have your helper turn off the AC then turn off the engine and after everything stops moving quickly touch the accumulator to see if its cold. Next check to see if one of the hoses running to the compressor is sweating (the short metal part that the rubber flex hose is crimped to at the compressor). If you can touch the short metal hose touch it to see if its cold. Again, be safe.
If they are sweating and are cold then...
2. If the AC controls and the heater controls are all on the dash in the same unit (like 1990 Chevys) then first check to be sure that the hot water valve to the heater core is closing and stopping the hot water flow.
The heater core will always overrun the AC evaporator. These valves can stick over the course of the winter then in the summer will not close and make it seem that the AC is not working. I have taken Vise grips and closed them on the heater hose to test this. Do not cut the hose.

Beginner