2002 Massey 4345 ac issue.

[zeroo]

howdy. Massey 4345 with 1400hr. This tractor lost its compressor around 2007, probably about 500hr on machine. Blew a hole right in the side. Got it fixed and seemed to work good. Last year it started not cooling good so I got a can with a hose and went to town. Even put some oil in! So compressor started kicking off. Honestly not sure how much of each I put in, if any at all cause I don’t know if high pressure or low pressure was kicking compressor off. Called guy who replaced it years ago and he put gauges on and got it going. I don’t remember if he added. He did say any extra oil would cause problems.

Educated myself a little, got some guages and a vac. Guages were low 20ish/225 on 90f day. Cooling wasn’t the greatest.I added a little refrigerant and cooling seemed better. But I wanted to start clean and fresh and get any unwanted oil out so borrowed a recovery machine. Flushed evaporator and condenser, replaced drier and txv. Drained what little oil was left in compressor, probably not even an ounce. I assume recovery sucked it out. Put in oil, vac’d, tested, vac’d for an hour more and put proper amount of Freon. Cooling is better, with cab wide open ac fan on high and 88f vents blowing low 50’s. Cab closed recirculating air it gets pretty cool, maybe upper 40’s. But readings were 25-30/315 at idle. When rpm’s raise both drop, maybe 10-15/275.

The condenser is the old kind with big tubes. Also, the batteries sit right in front of it. You would think it would hinder air flow.

I guess the the only thing left is to take it back down and replace condenser and evaporator. Then the compressor I guess unless there is something I’m missing. I blew out radiator and condenser then washed with water. They are very clean, the evaporator was really clean. Did change cab filter because the old one didn’t let much light through. I would just blow dust out with the shop air, but I guess I should have replaced it a wile ago.

As of now it feels about as cold as it ever was, I think. Wonder if this is as good as it gets? I really won’t know until I’m bailing in the heat with tractor running wide open. But with the low suction at high rpms, could that be what took out the original compressor?

[Cornbinder89]

Your high side is higher than I'd like to see at that temp. If your sure you have the recommended charge by weight, I would try "misting" the condenser with a hose to see if the high side drops a lot and the cooling improves. Low pressure on the suction with a Tx valve system can be a cause for concern but it also can be normal if the compressor capacity is large and is driven at high speed.
If the (thermal) bond between fin and tube is poor on the condenser, or the air flow isn't the greatest, it can be hard to shed the heat from the refrigerant.
I don't know the machine you are working on, I'm more a heavy truck guy, where Is the condenser in relation to the other components? Is the air drawn in the side and blown out the front like some tractors, or is it more like a motor vehicle where it is drawn in the front?
The parallel flow condensers do a really good job of heat transfer for the size, but they can restrict the air flow to the radiator if they are in front of them, that could be a problem on hard working tractors and the reason they used tube and fin type. Also they would tend to clog with chafe easier that a tube and fin with larger space between the fins.
Also temp/pressure comparison are only valid when you know the temp of the air passing thru the condenser, it may be 90 deg outside but if that air is picking up engine heat (like it might from air drawn in the side and blown out the front) the condenser will "see" much higher air temp. If that is the case, your numbers and cooling may be as good as it will get.

[zeroo]

The condenser is the bottom one, right behind the batteries. The tractors cooling works great, 95f out with tractor wide open pulling a round baler it doesn't go past half on the temp gauge. but with everything hot that's when the ac was struggling. I checked gauges today with cab wide open and fan on high. 28/312. it cools good, but I will not know how well until I'm working it hard. Also the refrigerant capacity is 1.5kg.

[Cornbinder89]

Looking at how it is stuffed in there, I'm not sure you can expect much more, It is much like my Cabover Semi tractors. Lots of external heat, large glass area, hard to build a climate control system that can handle all that.
Anything you can do to get the heat out at the condenser will help, but you are still limited by the size of the evaporator.
Ideally I'd like to see the high side lower, but I'm not sure, with where the condenser is placed, that you can improve it much. Make sure any baffles are in place and chafe screens are clean.

[zeroo]

Thanks...Ok so I used it tonight for a wile, longest I used it since doing the ac. Probably about 40 min. Left cab shut and thermometer at vent it was 40f. Felt very cold, like a walk in cooler. In the pics you will see the txv and the lines frosted. Not sure if that is normal. I don't know if opening the roof up to evaporator and tx made it frost, but I put a piece of insulation on txv and shut lid for about a minute. Reason why is there was some rubber type of insulation on original txv. Kind of like silly putty. Wanted to see if insulating txv top changed vent temps, but it just seemed to make the silver round top frost up more, so I left it off. Then I took some readings. Temp outside was 83f and at idle pressure was 5/175. At about 1800 rpms pressure dropped to 0/170. Also at this time vent temp raised to 48f.

This cab is designed to recirculate air, mainly because it keeps chemical mists out when spraying, so could I have froze up evaporator by trying to make cab as cold as possible, then opening door to evaporations and txv, because the conditioned air inside the cab was so dehumidified? Putting insulation on silver top of txv cause it to freeze up? With those readings it seems low on refrigerant.

[Cornbinder89]

I would agree with you assessment that those readings low charge, The question then is why was it so high before? 312 and 28? I wouldn't be to concerned about a little frosting at the Tx valve as long as the frosting doesn't extend back to the compressor.
Is it possible the frost switch or whatever the control used to prevent evaporator icing isn't working?
Next time you run the system try and feel the condenser and see if the temp gradually decreases from inlet to outlet. Ideally you want the outlet 10 deg or so above the air passing thru the condenser, If the outlet is too hot to touch, then I would say your not shedding enough heat, and you are low on charge, giving the high pressure on the high side and normal on the low, if that is the case and you increase the change you will see the high side rise and the low side stay more or less the same. You are nearing the limit on the high side at 312, much higher and you can loose hoses and may open a blow-off.
If you are sure you charged with the correct amount, and you are also sure of the pressure readings, you could try misting the condenser to see if the high side comes down without the low side dipping to near zero.
Is it possible that air is not going thru the evaporator but around the outside?
I must admit I am kind of lost with the pressures changing so much.

[zeroo]

one way it could be a little low is several gauge hook ups, and not realizing I should dump the high side into the low before I unhook.

[zeroo]

Update, 94 outside. My readings stay the same, 28/320 with all windows open and ac on high. This recirculates only so its sucking hot air in that way. Now, with cab shut and cooled off the pressures drop to the low readings.10/175ish. The colder it gets the lower the pressures. I did mist the condenser a little but no change. Probably didn't spray it enough, just used a spray bottle. I used an infrared thermometer and the upper parts of condenser are 190ish and lower parts are 130ish. This is a cheap thermometer and engine is all up to temps.

[Cornbinder89]

everything seam "normal" except the low pressure reading when the cab is closed. Not being well versed on the ag systems, I am wondering if they use some sort of evaporator pressure regulator so the compressor doesn't have cycle the clutch to maintain temps of around freezing. This may account for the low - low side reading when the heat load drops (cab all closed up). 175 psi equates to mid 130's for condensing temp which does match your IR temp readings.
320 is about 165 deg for condensing temp with a high heat load, not great but as you pointed out the batteries are right in front and the air-flow on a tractor isn't ideal.
I am wondering, as most AG application have a chafe guard on the clutch, if they don't use some sort of EPR so the clutch doesn't have to cycle while the tractor is working in the field, less chance of a clutch related problem from chafe getting into it, or heat build up and the chance of starting a fire with a slipping clutch? Just guessing here as AG is not something I deal with.
If the low side tap is on the compressor side of a EPR, it will read low when the EPR restricts the suction pressure in the evaporator to around 30 PSI
I guess I'd call it good if it will cool the cab closed up.

[zeroo]

10-4, thanks for the input. I will update with any extra info or if it changes. Always good to have model specific searchable posts.