John Deere 3520 - Air Conditioner Issue & Cleaning Radiator in Field

[Thowle]

Seems like I'm posting a lot of questions on here lately about the tractor... But the other day, it was 102 degrees outside, high humidity. Had AC on full blast, had been mowing about 10 hours.. Was blowing hot air. Cleaned cabin filter, radiator, and grille best that could be done in the field. Let tractor sit and cool off for a bit. It still wouldn't cool, except about every 5 minutes you could hear and see by the RPM the compressor engage for about 15 seconds, and you would feel a little cool air.

Think this is because it was so hot, and some sort of thermal switch causing it to operate in this manner to prevent damage?

Maybe low refrigirant? I didn't see anything in manual other than to take to the dealer. Could I not use automotive fill gauge and regular 134a?

Anything else it could be?

What does everyone else do or use to clean filters, radiator stack, and grille when in the field? Short of just buying an air compressor to go on the truck or trailer... I'm not sure?

 

[jenkinsph]

After 10 hours of mowing you might be better off to head back to the house and clean the radiator and condenser coil better. Kind of hard to do a good enough job in the field without the equipment you mentioned. I keep a Stilh backpack blower on my truck for this but still need to wash it out if it is really bad.

 

[BigMike50]

Seems like I'm posting a lot of questions on here lately about the tractor... But the other day, it was 102 degrees outside, high humidity. Had AC on full blast, had been mowing about 10 hours.. Was blowing hot air. Cleaned cabin filter, radiator, and grille best that could be done in the field. Let tractor sit and cool off for a bit. It still wouldn't cool, except about every 5 minutes you could hear and see by the RPM the compressor engage for about 15 seconds, and you would feel a little cool air.

Think this is because it was so hot, and some sort of thermal switch causing it to operate in this manner to prevent damage?

Maybe low refrigirant? I didn't see anything in manual other than to take to the dealer. Could I not use automotive fill gauge and regular 134a?

Anything else it could be?

What does everyone else do or use to clean filters, radiator stack, and grille when in the field? Short of just buying an air compressor to go on the truck or trailer... I'm not sure?

you have a warranty issue. I have a digital temp thermometer that takes inside and out temp readings on the 3520. I had readings with dirty filters where it was 101 degrees in july outside on the machine and 69.5 inside the machine on fan setting number 2. I had "as usual" a hood screen full of debris and radiator and condenser full of debri from dry clippings. I also have tinted windows but that would account for about 10 degrees cooler and granted the fact that I haven't had to use setting 3 on the machine. I always getting a ton of condensation on the windows due to the frost of the air coming out of the vents. You should not have to recharge your system. You have a leak somewhere. Because of the window tint, I have not had to run full seting number 3 in the cab but even so, it should be down right cold in there if you are running that machine that high on the hottest day of the year.

 

[RoyJackson]

Since I have an open station, can't comment on the AC issue.

For cleaning the radiator and grills in the field...get a 2" paint brush...a cheap one does fine. Cut the bristles down to 3/4" to 1" in length. This does a fine job cleaning dust, pollen and debris, especially on the grills. It's been my experience that keeping the grills clean is all that is really necessary. Do this cleaning when you start to see the temp gage climbing...don't wait until it's overheating. Do let the engine run at a fast idle under no load (mean no AC or PTO) for a few minutes. As long as you're going to clean the grills on the front and sides only (and NOT get into the engine compartment), you don't need to shut the engine down

 

[Thowle]

After 10 hours of mowing you might be better off to head back to the house and clean the radiator and condenser coil better. Kind of hard to do a good enough job in the field without the equipment you mentioned. I keep a Stilh backpack blower on my truck for this but still need to wash it out if it is really bad.

Not an option in this case. This will be at a job site.

you have a warranty issue. I have a digital temp thermometer that takes inside and out temp readings on the 3520. I had readings with dirty filters where it was 101 degrees in july outside on the machine and 69.5 inside the machine on fan setting number 2. I had "as usual" a hood screen full of debris and radiator and condenser full of debri from dry clippings. I also have tinted windows but that would account for about 10 degrees cooler and granted the fact that I haven't had to use setting 3 on the machine. I always getting a ton of condensation on the windows due to the frost of the air coming out of the vents. You should not have to recharge your system. You have a leak somewhere. Because of the window tint, I have not had to run full seting number 3 in the cab but even so, it should be down right cold in there if you are running that machine that high on the hottest day of the year.

Will let the dealer know... Seems like yours works awesome! Mine usually works good... It just started not keeping up that day.

Since I have an open station, can't comment on the AC issue.

For cleaning the radiator and grills in the field...get a 2" paint brush...a cheap one does fine. Cut the bristles down to 3/4" to 1" in length. This does a fine job cleaning dust, pollen and debris, especially on the grills. It's been my experience that keeping the grills clean is all that is really necessary. Do this cleaning when you start to see the temp gage climbing...don't wait until it's overheating. Do let the engine run at a fast idle under no load (mean no AC or PTO) for a few minutes. As long as you're going to clean the grills on the front and sides only (and NOT get into the engine compartment), you don't need to shut the engine down

Good idea. Will do this.

 

[greg_g]

Yeah, warranty. Compressor cycling sounds normal though. Possible leaking roof seal, or incorrectly adjusted temperature control cables. But if you haven't washed those foam screens inside the cab yet, they might be inhibiting air flow. IF the warm can't get out, the cold can't get in. Have you found them in your manual yet? If you don't know what I'm talking about, they're behind and above your head as you sit in the operator seat. Two easily removed trim pieces must come out to remove them. Helps to wash the trim pieces too.

//greg//

 

[murphy1244]

For your Rad get one of those portable Air tanks and mount that on your tractor or throw it in the Truck.

 

[PBettis]

Sounds like a classic refrigerant leak. The compressor is "short cycling" from low charge. The system has a low pressure switch tied to compressor clutch and when the ambient temp. raises the system's refrigerant pressure the corresponding rise in pressure activates (closes) the low pressure switch making continuity with ac clutch. As the system begins to operate the suction (vapor) side, which is the side with the low pressure switch, begins to develop a drop in pressure. Since there is a low refrigerant level the pressure drops below the cutout setting of low pressure switch which in turn re-opens the pressure switch. This switch is more or less a safety switch to keep your compressor from running with low oil return (no refrigerant). The oil/refrigerant that travels thru the compressor actually lubricates the moving components of the compressor and cools it as well. You can make some leak soap out of dishwashing detergent and water (mix thick) or buy the better stuff from HVAC supplier. With machine off spray all the fittings etc. I highly suggest not attempting to charge the system with little or no experience. Too much refrigerant puts a strain on the compressor and lowers the efficiency drastically (high pressure cutout) and too little causes the "short cycling" issue as well as lower efficiency. But, in a nutshell your system probably, most likely uses R-134a refrigerant which is fairly inexpensive and can be bought at the auto parts store. These cans are usually 12 oz. Or larger and come with a simple guage to read pressure/temp. to charge your system. If you can read directions you can charge your system safely. The hose only hooks to one fitting on the low pressure (suction/vapor) side of system. I would spend some time trying to locate the source of the leak before adding refrigerant. If unable to locate leak just add some refrigerant to get you thru the hot months and tackle the project in the winter. Hope this helps!

 

[jenkinsph]

Sounds like a classic refrigerant leak. The compressor is "short cycling" from low charge. The system has a low pressure switch tied to compressor clutch and when the ambient temp. raises the system's refrigerant pressure the corresponding rise in pressure activates (closes) the low pressure switch making continuity with ac clutch. As the system begins to operate the suction (vapor) side, which is the side with the low pressure switch, begins to develop a drop in pressure. Since there is a low refrigerant level the pressure drops below the cutout setting of low pressure switch which in turn re-opens the pressure switch. This switch is more or less a safety switch to keep your compressor from running with low oil return (no refrigerant). The oil/refrigerant that travels thru the compressor actually lubricates the moving components of the compressor and cools it as well. You can make some leak soap out of dishwashing detergent and water (mix thick) or buy the better stuff from HVAC supplier. With machine off spray all the fittings etc. I highly suggest not attempting to charge the system with little or no experience. Too much refrigerant puts a strain on the compressor and lowers the efficiency drastically (high pressure cutout) and too little causes the "short cycling" issue as well as lower efficiency. But, in a nutshell your system probably, most likely uses R-134a refrigerant which is fairly inexpensive and can be bought at the auto parts store. These cans are usually 12 oz. Or larger and come with a simple guage to read pressure/temp. to charge your system. If you can read directions you can charge your system safely. The hose only hooks to one fitting on the low pressure (suction/vapor) side of system. I would spend some time trying to locate the source of the leak before adding refrigerant. If unable to locate leak just add some refrigerant to get you thru the hot months and tackle the project in the winter. Hope this helps!

While you may very well be correct I would start by cleaning the filters, radiator and condenser coil. If this doesn't solve his problems then at least it will be clean when he takes it to the dealer. Since the OP isn't an hvac technician and the tractor is a 2012 model let the dealer fix it. As you know most people start by adding refrigerant instead of properly trouble shooting the system, I have always disliked coming behind these people to do the actual repairs.

 

[PBettis]

While you may very well be correct I would start by cleaning the filters, radiator and condenser coil. If this doesn't solve his problems then at least it will be clean when he takes it to the dealer. Since the OP isn't an hvac technician and the tractor is a 2012 model let the dealer fix it. As you know most people start by adding refrigerant instead of properly trouble shooting the system, I have always disliked coming behind these people to do the actual repairs.

I agree. Spend the time to troubleshoot correctly first. I also agree to service the most common items first like coils and filters. I didn't catch the year model with the issue. Of course if it's under warranty it should be taken to the dealer for service. It may be there for a few weeks until they feel like repairing but that's besides the point.