Too much freon???

[Coyote machine]

That's what I don't understand either.

I bought it with about 250 hours on it and I put another 1000 on it and I don't have any record of any maintenance to the AC, other than the belt about 300 hours back.

So you had someone change the belt for the compressor? Is it possible they also added Freon to the system at the time? IF the system is/was overcharged at some point, causing your no AC condition, someone had to have added Freon to create the problem in the first place....

 

[Complete Turf Care]

So you had someone change the belt for the compressor? Is it possible they also added Freon to the system at the time? IF the system is/was overcharged at some point, causing your no AC condition, someone had to have added Freon to create the problem in the first place....

Yes, someone changed the belt. It was done at the same time we had to do some work on the exhaust manifold. While they had the hood off it was easy to change the belts, and there were about 1000 hours on them. I don't recall adding any Freon at that time, because the AC was working fine.

There was never a time that the AC did not work. I did notice that it did not cool very well at low engine rpm's. The main reason for working on it this time was because the belt would squeal each time the compressor kicked on. This seemed to happen a lot more lately.

I picked it up from the mechanic Friday morning and only had about 10 minutes to run the tractor. I hit the AC on/off button several times and it did not squeal. I know the compressor was kicking off and on because I could hear a change in the engine. Temperature was in the mid 70's but I don't know if that makes any difference.

 

[Coyote machine]

At low engine RPMs, idle or slightly above, the compressor wouldn't be able to output as much cooling as when at operating speed, or workload speed(s).
So is it working flawlessly now?
Are your ambient temps high enough currently to 'test' its function?

 

[Dave M7040]

I googled something like "ac belt squeals when compressor starts" and most of what I found was that belts were loose or worn. I didn't think that was my situation. I found a few discussions that said it could be the clutch.



Yes, the belts were changed about 300 hours back when I had some work done on the exhaust.

This mechanic is about 70 years old and knows his way around tractors. I doubt he has had any formal AC training, but he has been around. He said he checked the pressure and it was too high, so he let a little 'refridgerant' out and it seemed to solve the problem.

I guess I will find out when I get on a job with it........

I am 72 and my AC experience was gained when refrigerants were a single gas. R12, R22, R11.

Now the modern gases are mixtures of two or more gases each behaving a little differently.

A refrigerant may be either a pure compound or a mixture (blend) of two or more refrigerants. ... Examples of mixtures are R502, R404A and R407C. A mixture can behave either as a pure refrigerant (azeotropic mixtures), or differently (non-azeotropic, or zeotropic, mixtures).

I am not up to date with refrigeration but know enough that just adding or removing gas from the system is the wrong way to do servicing. As someone else mentioned, evacuating and then recharging with the proper amount is the only way to do the job.

If I was in your shoes, I would search out a highly respected AC technician. Have him evacuate and recharge. He will also replace the drier. Your tractor's AC system is an expensive one and you don't want to be running it with on not enough refrigerant or with some Walmart refrigerant in a can solution.


Dave M70470

 

[Complete Turf Care]

At low engine RPMs, idle or slightly above, the compressor wouldn't be able to output as much cooling as when at operating speed, or workload speed(s).
So is it working flawlessly now?
Are your ambient temps high enough currently to 'test' its function?

I have not had a chance to use it yet. Our temps are still in the mid 90's and will be for some time. As soon as I get to use it, I'll post my observations. Thanks for your replies.

If I was in your shoes, I would search out a highly respected AC technician. Have him evacuate and recharge. He will also replace the drier. Your tractor's AC system is an expensive one and you don't want to be running it with on not enough refrigerant or with some Walmart refrigerant in a can solution.


Dave M70470

I believe this is good advice. I have learned a lot about AC's in this thread. And that is why I started this thread. I'm just not sure where to find a trustworthy AC technician. But I will look. Thanks!

 

[TractorGuy]

Are sight glasses still used for auto AC systems? How about on tractor AC? Back when I had my shop we had a Snap-On AC station that included a vacuum system, a charge tank for old style Freon, and gauges to read pressures in the lines, etc., and an in-line sight glass where one could see flow of Freon through the glass. One could see if there were too many bubbles in the flow - and indicator of not enough Freon charge in the lines.

My backhoe drier has a sight glass but it's a waste of time to look at it. It only calls for a charge of 1.65 lbs and at that the sight glass is full foam. Trying to put any more refrigerant in results in the system not cooling as it should and engine running warmer from elevated condenser temperatures and the sight glass remains full foam. I put 3 cans in one time trying to clear up the glass and it didn't change other than I had to evacuate and start over.

Seems like a very low capacity for such a large looking system but it is what it is. If I have to have it open to repair a leak (which I have) I just put it under a vacuum for an hour or so and charge it with 2, 12oz cans and call it good. I would rather run it 2 oz low than crack a third can to leave on the gauges.

 

[gimmodog]

a dirty condenser not getting enough air flow to take the heat out of the refrigerant will cause you to get a high pressure reading. this could have been the problem and he didn't think of it just thought too much refrigerant. cleaning the condenser should be done as a regular maintenance routine just like cleaning the evaporator filter. the fan blade is drawing all kinds of debris into the condenser, it must be cleaned occasionally. before you run it again make sure your condenser is clean.

 

[TractorGuy]

a dirty condenser not getting enough air flow to take the heat out of the refrigerant will cause you to get a high pressure reading. this could have been the problem and he didn't think of it just thought too much refrigerant. cleaning the condenser should be done as a regular maintenance routine just like cleaning the evaporator filter. the fan blade is drawing all kinds of debris into the condenser, it must be cleaned occasionally. before you run it again make sure your condenser is clean.

Good point.

I made a wand out of some copper tube to wash mine out with. Dirt seems to collect in the radiator behind the condenser.

FYI do NOT use a pressure washer on a radiator or condenser. It will fold the fins over flat.

 

[Complete Turf Care]

a dirty condenser not getting enough air flow to take the heat out of the refrigerant will cause you to get a high pressure reading. this could have been the problem and he didn't think of it just thought too much refrigerant. cleaning the condenser should be done as a regular maintenance routine just like cleaning the evaporator filter. the fan blade is drawing all kinds of debris into the condenser, it must be cleaned occasionally. before you run it again make sure your condenser is clean.

What is the best way to clean the condenser? Should I spray some cleaner on it and wash it out with the water hose?

 

[TractorGuy]

What is the best way to clean the condenser? Should I spray some cleaner on it and wash it out with the water hose?

Best to back wash it. If it's a typical fan sucking air through the radiator you would wash it from the fan side. If it's a blow through you would want to wash from outside. I just use water. Recently bought a pneumatic engine cleaning gun from HF that has a suction hose for soap I might try next time. If you use any kind of cleaner make sure it won't damage the metal in the radiator. Regular dish soap and water should be safe.