I have a 2004 L4330 Kubota tractor with a cab. It has 1000 hours and runs great except for the A/C. I have replaced the compressor, the evaporator, A/C switch in the cab, relay switch in the roof, installed a new expansion valve located in the roof. I cleaned the condenser coil and fan unit located in the roof. I vacuated the system and charged the system with Freon. The gauges read 45 on the low side and 250 on the high side. I am getting air in the cab but it is not even cool. The A/C switch in the cab is lit indicating the A/C is on. The compressor is running and the lines at the compressor are sweating and there is condensation running out of the drain tube located under the tractor. I did notice the sight bubble in the evaporator was hazy after we charged the tractor with Freon. Is there another relay in the roof that needs to be replaced? The local dealer does not work on A/C so they have been no help. Is there a manual that deals with A/C in Kubota tractors? I am not sure what else to do at this point. Any suggestions?...Thanks...DMcIntosh
Non Working A/C
- Thread starter DMcIntosh
- Start date
The WSM for your tractor should show you the locations of the relays. If you don't have a copy, it can be downloaded using the following link...
http://golftechs.us/Manuals/Kubota2.pdf
http://golftechs.us/Manuals/Kubota2.pdf
North Idaho Wolfman
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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
No free or cheap download for that model, your going to have to bite the bullet and buy a copy.
P/N 9Y111-08221
Thank you for your reply. I will download the WSM and go from there. I failed to mention that all of the radiators and screens are clean. Thank you again. Any suggestions of want to look for in the WSM?
Did you take into account ambient air temperature when setting the Freon pressure at 45 on the low side?
Did you measure the air temp from the outlet and ambient temperature? What kind of differential are you getting?
Did you measure the air temp from the outlet and ambient temperature? What kind of differential are you getting?
I don't know what is the problem with the air conditioner, but let me offer a few things to think about.
The sight glass is hazy which says that there are contaminants. Probably moisture which will lead to acid and that's bad. The refrigerant oil sucks up moisture when the system is opened and that moisture has to be removed.
The contaminated refrigerant can't be vented to the air. It has to be recovered into a DOT-approved recovery tank. It will have a yellow top and gray body. To get the refrigerant into the tank will take a recovery machine. Trying to use the compressor to move the refrigerant risks burning up the compressor. You can buy these items on the internet along with the hoses and cutoff valves.
The filter-dryer needs to be replaced whenever the system is opened. Then the system can be pressure tested for leaks.
That takes a dry nitrogen gas bottle, a gas regulator, hoses and valves. Vacuum down the system to remove air, and isolate the vacuum pump with a shutoff valve. Then let nitrogen into the evacuated system to a relatively good pressure and valve off the nitrogen. Look at the connected high pressure gauge to see if the presssure holds. If it holds for a period of time then there are no leaks.
Next is to pull all moisture out of the system. That will take the vacuum pump and a gauge which will read down to 500 microns vacuum. The nitrogen can be vented to the air. Pull the vacuum three times, breaking it with dry nitrogen. Each time pull a vacuum to 500 microns and watch to see if the vacuum holds. If the vacuum doesn't, then there is a leak or moisture is coming out of the oil. If it looks good on the third vacuum, now it is ready to charge with refrigerant.
Don't turn on the compressor when the system is in a vacuum. Either on the system or in the WSM it should tell what the refrigerant charge should weigh. That will get it close, and then tweaked to either subcool or superheat as depending on the expansion device. That takes a gauge set and thermometer. It also takes a refrigerant table to convert pressures and temperatures if not on the gauge set. If the refrigerant is R134a, it can't be mixed with any other refrigerant (gauges, hoses, recovery tank) because the oils are not compatible.
Then take in the recovery tank to have it emptied by a processor - it can't be vented or abandoned.
I'm assuming that the new compressor came loaded with oil. If it didn't, the correct amount of oil (particular to the refrigerant) will need to be added or injected (without picking up moisture).
The sight glass is hazy which says that there are contaminants. Probably moisture which will lead to acid and that's bad. The refrigerant oil sucks up moisture when the system is opened and that moisture has to be removed.
The contaminated refrigerant can't be vented to the air. It has to be recovered into a DOT-approved recovery tank. It will have a yellow top and gray body. To get the refrigerant into the tank will take a recovery machine. Trying to use the compressor to move the refrigerant risks burning up the compressor. You can buy these items on the internet along with the hoses and cutoff valves.
The filter-dryer needs to be replaced whenever the system is opened. Then the system can be pressure tested for leaks.
That takes a dry nitrogen gas bottle, a gas regulator, hoses and valves. Vacuum down the system to remove air, and isolate the vacuum pump with a shutoff valve. Then let nitrogen into the evacuated system to a relatively good pressure and valve off the nitrogen. Look at the connected high pressure gauge to see if the presssure holds. If it holds for a period of time then there are no leaks.
Next is to pull all moisture out of the system. That will take the vacuum pump and a gauge which will read down to 500 microns vacuum. The nitrogen can be vented to the air. Pull the vacuum three times, breaking it with dry nitrogen. Each time pull a vacuum to 500 microns and watch to see if the vacuum holds. If the vacuum doesn't, then there is a leak or moisture is coming out of the oil. If it looks good on the third vacuum, now it is ready to charge with refrigerant.
Don't turn on the compressor when the system is in a vacuum. Either on the system or in the WSM it should tell what the refrigerant charge should weigh. That will get it close, and then tweaked to either subcool or superheat as depending on the expansion device. That takes a gauge set and thermometer. It also takes a refrigerant table to convert pressures and temperatures if not on the gauge set. If the refrigerant is R134a, it can't be mixed with any other refrigerant (gauges, hoses, recovery tank) because the oils are not compatible.
Then take in the recovery tank to have it emptied by a processor - it can't be vented or abandoned.
I'm assuming that the new compressor came loaded with oil. If it didn't, the correct amount of oil (particular to the refrigerant) will need to be added or injected (without picking up moisture).
Stmar,
Here's a location for a free download of the WSM for the B2050, B2350, B2650, and B3150.
https://www.manualslib.com/products/Kubota-Wsm-B2650-4110033.html
When the site opens, click on the icon of the WSM that is located on the left. When that page opens, click on "Download".
Last edited:
DMcIntosh
If your tractor has a heater be sure heater control(coolant valve) is stopping flow of coolant through heater core when engine is running.
If your tractor has a heater be sure heater control(coolant valve) is stopping flow of coolant through heater core when engine is running.
BAP
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2012 Kubota 2920, 60MMM, FEL, BH65 48" Bush Hog, 60"Backblade, B2782B Snowblower
Where are you located? To get you A/C system worked on it doesn't have to be a Kubota dealer. Any brand tractor or construction equipment dealer can work on it even who does vehicle A/C. A/C systems in tractors are basically all the same no matter the brand.
IF your pressures are correct per first post, then the system seems to be working. Is the evaporator cold? Also, at what temp were the pressures measured? Was the condenser clean and able to allow free air flow across it? Spraying the condensor with water should (will) drop the high side pressure and should also drop the low side psi a little too, as well as you should see a drop in temp at the evap. Have you tried that yet?
Was ALL of the moisture out? Was the dryer/receiver replaced? If not, how long was the system open? What kind of gauges did you use? Digital or the old analog style? IF you have moisture in the system, typically you'd see the pressure gauge needles move around a little bit. Also, you'll see the high side psi on the higher end, and no "cool" air. But this is subjective in that the evap temp really needs to be measured. At 45 psi, your evap temp "should" be in the 65 degree range, which IMO, is not cold. Was 45 psi measured with the engine RPM elevated, or idling at 900 RPM or less?
In the a/c box there's also a heater core. If the blend doors aren't closing and opening all the way, you'll mix cold and warm air at the same time, giving you the effect of a non-working a/c system, even though the pressure gauge readings are saying it's working. Could be an issue? Have you looked at that stuff yet? All in the top of the cab.
Was ALL of the moisture out? Was the dryer/receiver replaced? If not, how long was the system open? What kind of gauges did you use? Digital or the old analog style? IF you have moisture in the system, typically you'd see the pressure gauge needles move around a little bit. Also, you'll see the high side psi on the higher end, and no "cool" air. But this is subjective in that the evap temp really needs to be measured. At 45 psi, your evap temp "should" be in the 65 degree range, which IMO, is not cold. Was 45 psi measured with the engine RPM elevated, or idling at 900 RPM or less?
In the a/c box there's also a heater core. If the blend doors aren't closing and opening all the way, you'll mix cold and warm air at the same time, giving you the effect of a non-working a/c system, even though the pressure gauge readings are saying it's working. Could be an issue? Have you looked at that stuff yet? All in the top of the cab.