Kubota Grand L 4610HSTC A/C

[patrickg]

Calling all Kubota L 4610HSTC owners and operators... I have never been satisfied with my A/C, have you? I am in hot humid south central OK and if it gets hot and humid enough to make you want to do tractor work to get the A/C and get out of the heat, then sorry, it is too hot and humid for the A/C to keep up. When it is marginaly comfortable outside in the shade and breeze then in the tractor with A/C it is hotter and less comfortable.

There is a screen in front of the A/C condensor as well as over the whole radiator. Both must be kept clean if you are to have a chance at being a "cool operator." You have to clean the filter at the top rear of the cab as well. With everything clean and the water temp gauge running nice and cool, I don't get enough A/C. Sometimes it will cycle between delivering cool air and warm air. I have had it to the dealer several times and they replaced the belt (slipping) showed me how to clean the filters and otherwise say it works fine.

It seems to work fine for them but they don't work it hard out in the sun, heat, and humidity. I'll be taking it back yet again B U T was wondering if this is a family problem or just my "luck". I don't expect to get frost bite but when it is cooler to open the doors and windows than to run the A/C, I think there is something wrong.

Pat

 

[ns_in_tex]

Pat,
I think we may have tractors that are underpowered in the ac department. Mine also leaves something to be desired, although I don't think it is as bad as yours sounds. Mine has always been more comfortable inside than outside.

Just the other day, after being uncomfortable in mine, I cleaned everything and tightened the belt (which was loose according to the book tension specs.) It helped some but I still need to run the engine fast to stay halfway cool in the hot sun.

I also was using 2 different tractors one day & was able to compare under same circunstances. The larger tractor air temperature at engine idle was 15/20 degrees cooler & several degrees cooler at high engine speed. The tractor would shortly make you hunt the controls to warm things up. It was putting out 45 degree air at high engine speed.

My kubota did not have any bubbles in the sight glass the day I serviced it, so I doubt it is low on freon. Probably just undersized.

The thought crossed my mind, wondered if I could speed up compressor speed by changing the pulleys, without damaging anything?

Another thing I wondered about is pulling the cab top, which I think is just raw uninsulated plastic (which all the return air has to pass under) & insulate it with something. Probably 1/4" styrofoam would help. I don't know how thick you could go before you might restrict air flow.

 

[ns_in_tex]

Pat,
You got my thinker to thinking /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif
Why not tie a piece of 3/4" foil back styrofoam over the top of the cab for a day or two, to see if it makes any difference.

If you come up with any good answers, be sure to let us know.

 

[patrickg]

Neal, I have had a few ideas: change out some components including compressor for larger ones and suffer the larger HP requirement to run the oversized unit, spray a mist of water on the condensor coil, insulation on top of cab, carry a 50 lb block of ice behind the seat.

Turn your A/C off and run the fan on high with the recirc/fresh lever in Fresh position. After temps stabalize does the supply air seem tooooooo warm. Mine does. The tech opened the top and checked the controls as I requested. I thought the hot water didn't shut off completely. He says it is OK but I'm still not convinced and will probably install a 90 degree ball valve in the hot water supply line as a test. When my A/C is working at its best I get cool air but having to overcome hot water can't be a good thing.

I will be taking it to the dealer to insure it is working to spec. Unfortunately, when supposedly working to spec it is not as good as I want. I actually hope I am getting some hot water flow because I can cure that and improve performance.

The dump trucks we are using to haul dirt at my house building site have manual valves to cut off the hot water to heater cores during A/C use. A/C was marginal before and good after. Apparently the heat control doesn't totally shut off the hot water. So the tractor tech and I could both be right. The controls could be completely turning the valve but still not stopping all the hot water. I guess one test would be to feel the water return line to the engine. If it is hot in an area away from excessive engine heat then there is flow. This might explain why the A/C seems to come on strong when the tractor is first started and then slacks off.

Pat

 

[Bird]

</font><font color="blue" class="small">( carry a 50 lb block of ice behind the seat )</font>

Nope, you need it in front of the seat. In the days before air-conditioned police sedans, I remember an officer who got in hot water because he put a block of ice in the front floorboard of his squad car. It might not have been so bad if he hadn't made drain holes in the floor with his .38. /forums/images/graemlins/blush.gif /forums/images/graemlins/laugh.gif

 

[patrickg]

Bird, So what was the problem, exactly? Were the drain holes too big, too small, to few, or too numerous?

Pat

 

[Bird]

Pat, it was against the written rules to "modify" city equipment without permission. /forums/images/graemlins/laugh.gif

 

[5030]

Pat:

I think I have your answer.
I have a 5030 HSTC and have been suffering with the same problem. One thing, the cab is all glass with a light tint. My sunburned arms will attest to that after 12 consecutive days from 9am until after dark in the 5030 running hay. If the glass was darker tinted it would help the ac, but there is another problem that i'm going to address myself. I notice that when I am travelling from field to field on the road at 15 mph., the ac works fine. When I am in the field, with an implement on, even though the rpm of the engine is about 2300, the ac won't keep up. Since I read this thread, i've checked the ac heat exchanger between the radiator and the oil cooler. It's always very hot. This tells me that there is not sufficient air flow through it to exchange the heated R-134 to a cool state. I religously clean the screens in front of the heat exchanger and the radiator at least 3 times a day and it makes no difference. What I am going to do is fabricate a tunnel of sorts, between the ac heat exchanger and the radiator, terminating just in front of the radiator screen. This will pull more air through the exchanger as well as the oil cooler. I believe that will eliminate the problem and will cool the cab appreciably better.

I've just finished my haying and have the 5030 in my shop for service. I'll probably make the tunnel sometime this week. I will keep you posted.

 

[frank_f15]

DON'T KNOW MUCH ABOUT the a/c in that tractor . but i do know about a/c. being a newer tractor i would imagine the refigerant is 134a, if it is up to proper charge, and all filters are clean, it just might be that the evaporator coil is a a bit undersized,some cars have the same problem, are u getting any cold air at all? and if so what is the temp of the discharge air?

 

[patrickg]

I haven't personally stuck a thermometer in it but when it works right it puts out cold air. Sometimes it seems to cycle on and off puting out cool air and then hot air when controls are maxed out for cool air.

If it puts out a lot of cold air and the cab is not cool then the A/C is just too small. That is a possibility but it has worked better than it is doing now. They changed the belt after I tried dressing and they tightened it and it still slipped. I will take it in for another service check AND I will check to see that there is no hot water flow. The controls turn the valve all the way. That isn't the problem. I'm concerned that along with whatever else is wrong, hot water is flowing through the heater core via the valve (maybe it doesn't shut completely???)

I don't operate much at night so maybe a dark tint would help. External blinds would be better but likely to get fouled in branches etc. External blinds ae better as they intercept the light and dissipate any heat externally. Inernal blinds add heat to the interior. Tinted windows help but the mirror type coating is better as it reflects energy instead of adsorbing it and transmitting half of it to the interior ike tint does.

Pat