Cab Owners- How cold does your AC get?

MidGALandscaper · Jul 3, 2006

I ran my cab 4720 tractor a good while Saturday and the AC never got cold. I know on some of the full size tractors you have to turn the AC down because it is too cold. I just want to check and make sure there is nothing wrong with mine before I take it back to the dealer. The AC is blowing fine, maybe a tad bit cooler than a regular fan. I am not sweating or anything, but I just want it colder.

rockyridgefarm · Jul 3, 2006

I am no help, but it may help to know roughly the ambient temperature, humidity, and the relative heat the engine was at...

Bird · Jul 3, 2006

The only air-conditioned cab I've personally operated was a bigger John Deere pulling a round bale hay baler and it was plenty cold. I once also got up in an air-conditioned cab of a Zetor, but didn't drive it. It was at a dealer who was demonstrating some hay balers, and it was plenty cold. And I did once see a nearly new Kubota M6800, brought to a mechanic because it wasn't cooling sufficiently while baling hay, and all it needed was to have the grass, seeds, dust, and other debris washed off the condenser coils on the front end. All of those were on very hot Texas days.

MrJimi · Jul 3, 2006

WARNING!! I am no AC guy! I do know any AC will only drop outside temp 30 degrees at the most! If its 90, your gonna see 60 . and if its 120? Your gonna see 90.
Its a 30 degreee drop IF its working good.
Jim

Dargo · Jul 3, 2006

In my Kubota L5030HSTC I made one change from the factory. I insulated the underside of my roof with aluminized bubble wrap. This thin layer of insulation is above my headliner and on the bottom side of the plastic roof clam shell. That made a pretty big difference.

Otherwise, as long as I keep my intake air filter (bringing in outside air) clean, and the two screens (one in front of the radiator and the other finer screen in front of the condensor) clean from seeds and pollen, I can actually get cold on a day like today when it is 98 degrees outside with 55% humidity.

If I let the tractor grill get clogged with seeds and junk, the screens covered, and my outside filter clogged, I can not get cold air. If you check all the above items on your JD and are not getting cold A/C, I'd have the dealer check your charge. On recirculate, I can put an HVAC thermometer in my vent and with the engine at 1800 RPM get temps in the low 40's to upper 30's. I know that sounds really cold, but there is so much glass in a tractor that you need good cold air. If my vents are aimed at the glass I'll get that area fogged over. Be sure to check your intake filter and screens for debris. Good luck!

Bird · Jul 3, 2006

MrJimi said:
WARNING!! I am no AC guy! I do know any AC will only drop outside temp 30 degrees at the most! If its 90, your gonna see 60 . and if its 120? Your gonna see 90.
Its a 30 degreee drop IF its working good.
Jim

I'm not AC expert either, but aren't you thinking of fresh air going across the evaporator? I thought you wanted a minimum of a 20 degree drop across the evaporator. So if you're recirculating air in the cab (or a house), the air coming off the evaporator should be 20 degrees or more cooler than the air entering the evaporator, and if the cab is already cooled down some, then even if it's 120 outside (ambient temperature) the air entering the evaporator should be cooler. Am I wrong?

MidGALandscaper · Jul 3, 2006

Thanks for all the responses, guys. I really appreciate it. The temperature was around 98 degrees on Saturday, with high humidity. And it has been extremely dry and dusty in this area. I will check all the tractor/cab filters again and blow out the front grill. Hopefully that will work. I kept saying to myself that the air should be colder, even though I know it is extremely hot outside and the tractor is working extremely hard with the power rake in hard clay soil. I remembered driving my uncle's new 4440 JD tractor back in the early 80's and that thing would freeze you stiff.

grmmrg · Jul 3, 2006

Be sure that not only do you have the cold air knob rotated to cold, but the hot air knob also rotated to the coolest setting.

tglass · Jul 3, 2006

Agree with Dargo, check you filters and radiator first. At 100 degrees and very high humidity I have to turn mine down after about 10-15 min.. Might be something simple to fix, but you definetly have a problem.

LRH · Jul 4, 2006

Have been looking at the 3*20 and 4*20 series and have noticed that there is not a recirc switch/lever from what I saw. Wondered if it used a head pressure switch to open recirc door. That being said; as humid as it is in GA, outside air is useless and recirc is a must. I have a dig temp probe in one of the vents of my truck, and after the cab is completely cooled and comfortable and reading 39-42°, I can switch to outside air and temp jumps to 48-54° , but feels much warmer and very damp and unless on a very low fan setting will not remove enough humidity although it is literally pouring out the drain hose... My question again is where is the ricirc/fresh air selector?

AltavistaLawn · Jul 4, 2006

I just took delivery of a 4720 yesterday. I played with it for two hours...

The ac go soo cold, I had to turn it off!

I'm off today to bush hog, and its supposed to be in the upper 90's here, so I'll report back at the end of the day.

JasonMac · Jul 4, 2006

My 3720 gets very cold. It definatly works as good as the heat does in the winter.

I have no problems with mine at all. I love it.

Chris_VA · Jul 4, 2006

MidGALandscaper said:
I ran my cab 4720 tractor a good while Saturday and the AC never got cold. I know on some of the full size tractors you have to turn the AC down because it is too cold. I just want to check and make sure there is nothing wrong with mine before I take it back to the dealer. The AC is blowing fine, maybe a tad bit cooler than a regular fan. I am not sweating or anything, but I just want it colder.

Be sure to keep your RPM's up to keep good airflow across the condenser. I assume your were operating at or near rated rpm's, but I thought I'd mention it in addition to what the others have suggested.

Chris

MidGALandscaper · Jul 5, 2006

I don't think there is a recirc/fresh air indicator. There is a toggle switch that turns the AC on or off (manual says something about de-icer, but it is not clear to me) but I don't think there is a recirc/fresh air selector.

I did find out why the AC wasn't getting cold. The cab filter was dirty, even though I cleaned it about 4 days earlier. With the extremely dry conditions here in GA, I will have to clean that filter every day or every other day. It is working much better now. I also cleaned the condensor and radiator up front. Thanks for all the suggestions.

Dargo · Jul 5, 2006

MidGALandscaper said:
I did find out why the AC wasn't getting cold. The cab filter was dirty, even though I cleaned it about 4 days earlier. With the extremely dry conditions here in GA, I will have to clean that filter every day or every other day. It is working much better now. I also cleaned the condensor and radiator up front. Thanks for all the suggestions.

Ah, ha! Do I get the prize for knowing what it was?

I'll give you one guess as to why I know that.

MidGALandscaper · Jul 5, 2006

Dargo, I assume you had the same problem too. I went ahead and ordered a couple more cab filters from my dealer today. As dusty as it is, I may start changing them out every other week. We need rain, bad! I think we are approaching a 12" deficit for the year.

LRH · Jul 5, 2006

How much better was it after everything was cleaned up; noticeable or quite significant? Seem if the filter(s) were restrictive to the point of extreme loss of capacity the airflow would have been reduced a lot.. I have always went to extremes to make sure condensers are clean, no bent fins, and air is not short circuiting around through gaps. I do the same on evaps and filters. A verey dirty filter on a car/truck/tractor will cause the compressor to cycle off more often to prevent freeze-up. (on models with t-stat probe in evap fins). I still wonder how these models switch between recirc/fresh air. Isn't there an inside as well as an outside filter to replace/inspect? Almost all equipment uses at least some outside air even on recirc to create a positive pressure to keep dust down inside.

MidGALandscaper · Jul 6, 2006

There was quite a significant different. The cab filter, located on the back side of the cab, got extremely dirty in about 4 days. I think that was blocking the air restriction by at least 40 or 50%. Kinda of wish that filter was located somewhere on the front, or even the side of the cab. When you are running PTO driven equipment like a harley rake in dusty conditions, the back side of the tractor and cab stays dirty. Oh well, I am still in love with this tractor. One of the best investments I have made. All that dust and dirt that the cab is blocking/filtering used to be all over me.