3720 Cab A/C Problem??

[radman1]

I used my 3720 last night. About 92F, cloudy and extremely humid. I had condensation all over the top of the cab, water dripping down the front window and down the drain tubes in the back. I had condensation inside the cab windows as well and it difficult to see outside. I was frequently getting in and out of the cab, which let more moisture into the cold cab air. This probably cause the inside condensation. I suspect for the high humidity, this was probably ok. The cloudiness, also didn't let the windows get hot enough to evaporate the condensation off the windows. However, it was really nice an cold inside the cab.

 

[sunnyside360]

I used my 3720 last night. About 92F, cloudy and extremely humid. I had condensation all over the top of the cab, water dripping down the front window and down the drain tubes in the back. I had condensation inside the cab windows as well and it difficult to see outside. I was frequently getting in and out of the cab, which let more moisture into the cold cab air. This probably cause the inside condensation. I suspect for the high humidity, this was probably ok. The cloudiness, also didn't let the windows get hot enough to evaporate the condensation off the windows. However, it was really nice an cold inside the cab.

Thanks for your help. Your experience is identical to mine but you have given a better more detailed description. I did some mowing today in same weather conditions except the sun was shining (vs cloudy) and I did not have any water dripping down the front & rear windows but there was a slight amount of wetness on the outside rear portion of the roof shell. Evaporation from the sun may have a great deal to do with it.
With the blower on high, medium and low I noticed there was considerably less air coming out of the right rear most exhaust duct as compared to the others so the duct may be disconnected. Probably the only way to know for sure is to disassemble the roof compartment and check it out.

 

[minimax]

I have had as much as a 1/2 inch of ice built up on my 3720 roof on a hot day with the A/C running hard.

minimax

 

[sunnyside360]

I have had as much as a 1/2 inch of ice built up on my 3720 roof on a hot day with the A/C running hard.

minimax

WOW!! It sounds like your A/C works very well (or maybe there is a air leak in the air box/ducting in the roof compartment). I've never had ice buildup -- just a lot of condensation & water. I don't think this is normal as I've had larger farm tractors with A/C systems which did not do this.

Just curious, does your heating system work very well, eg, a lot of heat?? I ask because mine does not get very warm and am thinking there may be air leakage in the ducting or air box. Running the engine at rated RPM's does help with heat but I think it should be better. Again, I'm only comparing with other tractors I've had.

Sunnyside

 

[minimax]

Heat works good.

minimax

 

[Silver_Knight]

I know this is an old thread but does anyone know why my A/C on my 3720 would cool sometimes usually until it gets in the mid to high 80s and then the temp coming out of the vents will go as high as 80-88 degrees? When it is cooling it will be 60 degrees coming out of the vents.

I have cleaned the roof filter and washed out the fins on the unit in front of the radiator.

 

[radman1]

60 degrees coming out the vent is way to high. I don't see how your cab is cool at all. You should be able to stay cool in 100 degree heat. Cabs are like small green houses. I had to add refrigerant to mine last year (1 can) and then it did great. Just recently took my 3720 to dealer to have seal in the front axle repaired under warranty. I had them check the a/c because of what happened last year and it seem a little poorer on cooling this year. However, the poorer cooling could have been my imagination. They added a little refrigerant (1/2 can) but told me the air coming out the unit was already at 30 degrees!
I did have a problem with the heat/cooling when I bought the tractor new. The tractor engine would never warm up when 35-40 degrees. After multiple trips to different dealers, calling JD techs and regional rep, replacing the thermostat etc, they did find major air leaks in the corners of the cab/air box. Once they were sealed, it worked great.

 

[Nuru]

Radman, do you know how they foind those leaks?

 

[radman1]

Nuru

The site of the leaks were in the air box at the corners. The first dealer and area rep missed them. I was told, they are difficult to see and are partially hidden from sight. The heater/ac was bringing in too much outside air which was mixed with the air in the cab roof/box. A clue that tipped off the second dealer, was placing a sheet of suran wrap over the outside filter box where the air is suppose to come in. The wrap would not suck into the filter box like it was designed. They also noticed some dust in the corners or the air box at the areas of leakage. The corners were not sealed properly at the factory.

 

[Nuru]

Nuru

The site of the leaks were in the air box at the corners. The first dealer and area rep missed them. I was told, they are difficult to see and are partially hidden from sight. The heater/ac was bringing in too much outside air which was mixed with the air in the cab roof/box. A clue that tipped off the second dealer, was placing a sheet of suran wrap over the outside filter box where the air is suppose to come in. The wrap would not suck into the filter box like it was designed. They also noticed some dust in the corners or the air box at the areas of leakage. The corners were not sealed properly at the factory.

Wow that actually is a very good way to find a problem.

Thanks!