Question for those of you who do air conditioning work. I'm curious about the freon weight of the various cab tractors. Assuming that spec would be found in the specific WSM for each model, but the few that I have been involved with all seem to be in the range of 2.0 to 2.5, 2.6 lbs. of R134A. Is that pretty much a standard for most of the Kubota cab model or do some hold more than that?
A/C charge weight
- Thread starter Fedup
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Assuming you are starting from a completely evacuated system, then the numbers you posted (2.0 to 2.5 lbs) is what I have seen most cab tractors.
It is always best to weigh in the amount specified, but you 'can' watch your gauges (for high and low pressure values) and compare against your vent temps.
Stay within the 'window' of pressures for the ambient temperature and watch your vent temps to note when adding more refrigerant no longer results in lower vent temperature.
Yes, the weight would only apply to an empty system. I was just curious about the differences between models because it seems with most other tractors the charge weight is higher than the Kubotas I've seen. Many are 3 lbs + but the Kubotas seem to be smaller systems.
Depends on the cab size and the compressor, condenser and evaporator used with respect to system capacity. I'm guessing the Kubota's use a Denso Compressor of some sort.
I'm not familiar with what they use but I am familiar with A/C systems if you require any help.
I just hope I don't have to buy any refrigerant. I think it's gone up more than diesel fuel.
Gone up about 1/3rd in the last year and half or so. Still about $9.00 a 12 oz. can at Walmart.
So if you had a 2 lb. system you'd be looking at 3 cans roughly. Tax and all.....30 bucks out the door. Not a high price to pay for cold air. Provided you don't have any leaks in the system.....it should last a long time.
Refrigerant is not a 'consumable' (like engine oil). It can only leak out or become contaminated over time.
I usually bought it in 30lb cylinder
In 2021 I bought a cylinder (March) for $78 and change.
I do some mobile A/C stuff (cars/trucks) on the side and go through about 30lb a year. Yes I can use recycled but I usually sell it and use new (although recycled is supposed to be good-I don't trust it). March this year, same cylinder, same brand, same place, over $400-close to $500. May be higher now. I'm not shopping it. It is what it is and I have a little left, and then I'm done.
I found some 12oz cans for dirt cheap at a local place and will use those if needed.
I like using the 30lb because when swapping the cans it's not unheard of to introduce a little bit of air while swapping cans. I want to limit how much air gets into the system.
vacuum is somewhat subjective. The majority of vacuum pumps won't pull a system down deep enough to be effective. If you can get 500 micron, that is considered decent. Most of the vane pumps I've seen won't get to 500. Lower is better but it's hard to find one that'll go lower than 500 microns.
Every tractor is different. The comrpessors, condensers, lines, evaporators, dryers, they're different between different models thus the refrigerant charge is different. Some have piston style compressors some are scroll type
the wsm charge specification is assumed that the entire system is new, fan, evap, all of it-because even a little dirt on the fan blades reduces the air flow from the fan, which changes the operating pressures of the a/c system. Dirt in the condenser, evaporator, it all makes a difference and that's why I used to get them at the shop too often with note on the R/O saying "owner attempted to recharge". Once that is learned, the repair changes. People will be using their equipment and the a/c will start to increase temperature over time and they automatically assume that it needs a can of refrigerant, so they run down to the parts store get a can and the hose, and stuff it in and then at the end of hay season the compressor seizes up and they're wondering why.
In 2021 I bought a cylinder (March) for $78 and change.
I do some mobile A/C stuff (cars/trucks) on the side and go through about 30lb a year. Yes I can use recycled but I usually sell it and use new (although recycled is supposed to be good-I don't trust it). March this year, same cylinder, same brand, same place, over $400-close to $500. May be higher now. I'm not shopping it. It is what it is and I have a little left, and then I'm done.
I found some 12oz cans for dirt cheap at a local place and will use those if needed.
I like using the 30lb because when swapping the cans it's not unheard of to introduce a little bit of air while swapping cans. I want to limit how much air gets into the system.
vacuum is somewhat subjective. The majority of vacuum pumps won't pull a system down deep enough to be effective. If you can get 500 micron, that is considered decent. Most of the vane pumps I've seen won't get to 500. Lower is better but it's hard to find one that'll go lower than 500 microns.
Every tractor is different. The comrpessors, condensers, lines, evaporators, dryers, they're different between different models thus the refrigerant charge is different. Some have piston style compressors some are scroll type
the wsm charge specification is assumed that the entire system is new, fan, evap, all of it-because even a little dirt on the fan blades reduces the air flow from the fan, which changes the operating pressures of the a/c system. Dirt in the condenser, evaporator, it all makes a difference and that's why I used to get them at the shop too often with note on the R/O saying "owner attempted to recharge". Once that is learned, the repair changes. People will be using their equipment and the a/c will start to increase temperature over time and they automatically assume that it needs a can of refrigerant, so they run down to the parts store get a can and the hose, and stuff it in and then at the end of hay season the compressor seizes up and they're wondering why.
Pau7220
Well-known member
Equipment
L3650 GST, Landpride TL250 FEL w/ Piranha, 6' King Kutter, GM1084R Finish
Lugbolt… Auto Zone has 30 lb virgin 134 on sale this week through the commercial back counter for $299
Thanks.
I called local store. $380 + taxes. "On sale". Oreilly 2 blocks away is $472.99. I found a different source. Well it's the same source but different circumstances. I gotta go through someone else who has different credentials.
What's behind the the question of how much refrigrant is needed, is the system not functioning properly are the coils fouled, leaks, etc.?
To be honest, the question is more one of curiosity than anything else. Most tractors I see hold closer to 3 lbs. but they have larger compressors, larger condensers and evaporators.
My experience with Kubotas is limited, I admit, but I know owners who claim their tractor systems don't cool as well as some of the other brands they own. I've worked an a few that cooled surprisingly well for what I consider a small system (component wise), and others that seem to be less than they could be, even when pressures look good, coils are clean, blower fan and cab airflow seem adequate, all that.
I see a number of posts from those who portray themselves to be "in the know" about A/C servicing, citing all sorts of theory, specs, numbers, even charts of pressures compared to ambient temperatures, etc. I seem to come across them frequently enough. The refrigerant charge weight (down to the gnat's _ss) is usually paramount in the diagnosis of whatever current problem is under discussion.
Not that it matters to this discussion, but I'm dealing with an M5 111 right now that has some issues. That tractor has a little Denzo compressor that's about as small as any I've seen. I think the alternator is bigger. The condenser can't be more than 12" square, and placed in front of an intercooler, about 6 or 8 inches away from the radiator and right behind the battery. How the engineers ever expected it to get much airflow is beyond me.
My experience with Kubotas is limited, I admit, but I know owners who claim their tractor systems don't cool as well as some of the other brands they own. I've worked an a few that cooled surprisingly well for what I consider a small system (component wise), and others that seem to be less than they could be, even when pressures look good, coils are clean, blower fan and cab airflow seem adequate, all that.
I see a number of posts from those who portray themselves to be "in the know" about A/C servicing, citing all sorts of theory, specs, numbers, even charts of pressures compared to ambient temperatures, etc. I seem to come across them frequently enough. The refrigerant charge weight (down to the gnat's _ss) is usually paramount in the diagnosis of whatever current problem is under discussion.
Not that it matters to this discussion, but I'm dealing with an M5 111 right now that has some issues. That tractor has a little Denzo compressor that's about as small as any I've seen. I think the alternator is bigger. The condenser can't be more than 12" square, and placed in front of an intercooler, about 6 or 8 inches away from the radiator and right behind the battery. How the engineers ever expected it to get much airflow is beyond me.
The issue(s) with trying to cool cab tractors are primarily the large window area (Solar Gain) and the inherent low speeds at which the machine is normally operated.
Neither of these things lend themselves to efficient cooling of the cab.
Tinting the windows and insulating the roof of the cab can certainly help. Also consider installing a 'manual' shut off valve in the heater hose circuit....so you aren't battling that (if not fully closed).
Depending on the tractor....you may or may not be able to do anything about moving more air across the condenser. You'll never have 'ram air' like a vehicle going down the highway, so your engine fan (and any aux fans) bear the burden of moving all the air.
Remember also....that your A/C SYSTEM is just that (a system) each and every component must be in good working order (Compressor and Clutch working well, Condenser and Evaporator Coils clean, drier not saturated, correct refrigerant and oil levels, no air/moisture in the system, blower fan working properly) etc.....