AC Conversion problem in 4455

So we just converted our 4455 from R12 to R134, and a whole crap ton of nothing..
To be clear, I will go over every little thing we did to it:
All new lines, High side, Low side, and the one going to the condesor, all new o-rings, low pressure switch works properly, New air dryer, updated fittings, the low side peice on the pump was replaced cause the threads fell apart, internals looked okay, 3 ounces of pag oil chased by 6 cans R134.Gauge was going up and down like the compressor was working, we were reading kinda high on the low side pressure.
The only thing we didn't do that I think might be screwing us up is evacuating the system, but the system had no R12 left in it, due to the changing of the hoses and air dryer.
To say the least, I am kinda stumped. What else could be going on?

If you didn't vacuum it out so as to put a vacuum in the system before you started that could well be where your problem is. I was going to switch my car out to 134A and was told I would need to have the system vacuumed out so that it would take a charge like it should. I lucked out and a friend who I give veggies to had a can or R-12 and not I call my car the freezer

It is always absolutlely essential to thoroughly evacuate any AC system of all air and moisture before a new charge is introduced. Failure to do so can lead to failure or an inoperative system. If one has the tools, a vacuum should be drawn for at least an hour.

With all that apart I would have had a vacuum pump on it for probably a couple hours. I got no idea of what the capacity of a tractor is, 6 cans sounds high to me. Must be a decal somewhere with r12 capacity, think 134 conversions are 85% of r12 cap.

It is way overcharged. Take out 3 cans, well, pull it all out and evacuate it unless you live in the high and dry desert. Change the condenser to one that will work with 134 and you may have to change the compressor just to have a nice new one. 72 ounces is way to much 134(6 cans). If it has an expansion valve instead of a tube it may not like 134 either.

Start over with an evacuation and then charge it to 36 to 40 oz of 134 and see what happens.

I'm thinking your expansion valve is clogged,, I would drop it all out,,change the expansion valve and then draw vacuum on it for a couple hours then add 4-5 cans of 134 into it. 6 is too much, and I think 3 is a bit light,, I have been doing 5 with good results..4 may be closer to being exact..I have not changed a condenser for years, and that was because a stick ran through it...

I guess its only money, whats another hundred bucks? Alright, I will get a pump and evacuate it. Hopefully we didn't screw anything up. My dad and I both kinda thought that was the problem. Our neighbor, who works at Wagner in the shop, said nothing about evacuating it. We figured he must know what he's talking bout but guess not. It is hot here on the Colorado/ Utah boarder. Bout 101 today. One other detail I didn't mention is the pump has not been charged in probably 5-8 years. Thanks for all the help.

Where is the expansion valve? It is on the compressor correct?

It's up on top under the inner roof, be careful when you take the lines loose and extra careful on the little one the metal nut will want to hang onto the aluminum threads...

You don't have to evacuate it; depends on where you live. I haven't sucked one down in thirty years. Mix R12 and 134 all the time.

You are WAY overcharged by at least 2 to 3 cans.

Allan

I agree with evacuating the system. air in the system will mess with pressures. Something to keep in mind is if your low side pressure number was above the air temp. number you may of pumped liquid though your compressor and bent the reed valves. I don't know your system so I am talking generic. Its been awhile but I believe if you don't know how much R134 you need put just enough for the compressor the cycle then add till you have 35# on the low side and if everything is working right about 100# plus air temp on the side. like I said its been awhile so others may have better info. Good luck.

5 cans (12 ounce) is 2 ounces over the recommended charge for r-134a. Deere service bulletin says 58 ounces for best performance. I usually use 5 cans and have not had any problems.

So if I dont need to suck it down, what else could be wrong? A compressor cant compress air, so could there be an air lock? Yes I do know I'm over charged, dad went a little crazy.

My John Deere chart (I am thinking 4455 is John Deere) shows 3.6 pound of R 134 & 4 pounds of R 12. My experience is that mineral oil and R134 do not mix well in generous amounts but will tolerate some. I always use Ester oil as it is more compatable with mineral oil that was in R12 system. PAG oil and mineral oil are not good together. In fact PAG has several different series of oils and they suck up moisture like a sponge. You need to flush that whole system of lines and condensers, evaporators. You do not flush pump and drier. Have to get all that oil out that is possible. Might as well start over.

Since the system was opened up to replace the receiver/dryer, hoses, and other parts, there will be a lot of air in the system. That air never compresses to a liquid so there will be problems with the system until the air is removed.

You probably overcharged it ..which is worse then not having enough...to do it properly use gauges ..I have a 4455 and I'm thinking its 56 ounces

Likely plugged with gelled up oil. I did not read anything about you cleaning all the old mineral oil (flushing)out of the system before you added the PAG oil. If so a mixture of mineral oil and PAG oil will plug everything.

If your not starting with a perfectly clean, flushed system, use Ester oil, it is compatable with mineral oil, where PAG is not.

And yes, pump all the air and moisture out before recharging. You haver some work ahead to flush all that dukes mix of crap out of the system, including the compressor.

What are the gauge readings?

1. If both are roughly the same mid-scale, the compressor has lost a valve.
2. If the high side is too high and the low side is too low, the system is plugged.
3. If both are low, not enough freon.....or a massive leak.
4. Too much freon will lock up the compressor and the relief valve should pop off.
5. Is the compressor even turning... I.E. pressure switches?

You should get 'some' cooling after the 2nd can.

Allan

Agree

You need to get some pressure gauges. Everybody here is certainly trying to help but without some pressure readings they are all total guesses

I have to wonder why you changed it over in the first place. Did you have leakage? Compressor failure? Leaking hose(s)?
Having said all of that, here is a quick primer on A/C systems.....
First, the system works on compressing the refrigerant into a hot gas. This gas is then condensed into a liquid. The liquid is then fed through a metering device into an evaporator where it then returns to a gaseous state. When this happens, it absorbs a tremendous amount of heat. This is what gives you the cooling effect.
Now, two things are DEADLY to an A/C system: air and moisture.
Air is a non-compressible gas in this context in that it CANNOT be compressed into a liquid. Since it is evaporation of a liquid that does the real work, air simply reduces efficiency to the point that you may not get any cooling at all.
Moisture becomes a problem as it will collect and freeze at the point of evaporation and ultimately clog up the system. Moisture also reacts corrosively with R-134a oils to drastically shorten compressor life.

So, to solve your problem, do the following:
1) Use a recovery machine to remove all old refrigerant and oil from the system.
2) Evacuate the system to remove as much air and moisture as possible.
3) Add a proper oil charge for the system. Typically, there are specifications for how much each component will take.
4) Charge up the system using GAUGES, not can count or "seat of the pants" guesswork. Use a charging chart to determine the correct pressures to achieve for your ambient conditions.

A word about oils: R-12 systems used a mineral oil. This oil circulated through the system and kept the compressor lubricated. R-134a systems cannot use mineral oil because it will not circulate in the system using R-134a. As such, use of ester oils or PAG oils is required. These oils WILL circulate through the system and keep the compressor lubricated. PAG oils and mineral oils are incompatible. Ester oils are somewhat compatible with the left over mineral oil that may be still in the system.

FYI: Most work on tractors and implements are effectively repaired with "farmer fixes." However, systems using electronics and refrigeration systems are NOT compatible with "farmer fixes." These systems need to be serviced by knowledgeable and qualified repair personnel. Don't mean to hurt anyone's feelings. That is just the way it is. Sorry.

(quoted from post at 18:10:49 07/25/15) Where is the expansion valve? It is on the compressor correct?

Click to expand...

Expansion valve is encircled in blue on evaporator.
RE206757 Control Valve - CONTROL VALVE, EXPANSION ADD 45.51 USD

Went through this on a JD 2355 awhile back, the compressor kept leaking freon after a few months. Need to flush system with solvent, disconnect every place you can and flush out. replace all orings. Clean/wash evaporator and condenser fins. Most important part is replace old A-6 compressor with a new S-6 compressor. The old A-6 is 1970's technology and the S-6 is newer Tech with seals that hold up to R134a.
A company out of Fort Worth/ Dallas sell the S-6 compressor. The system will hold about 80 % R-134a compared to R12. Use the correct oil for R134A. The reason for flushing is that the R12 oil and R134a oils react. The Cool pro S-6 compressor 1-888-289-1309. You will to pull a vacuum on the system.