Freaking Air Conditioner on the 3720 Cab

[nmu98]

I was out taking care of a few tall weeds that grew up around the cedars with my 2 year old son. The first issue was that he got too cold with the A/C on level 2... Had to turn it down.

Then he went in and I turned it up a bit. I was in the field for 30 minutes total. I would see a drip on the window ever so often. I stopped to put everything away, and I get out to see ICE, yes ICE on the roof. I ran in to get the camera, and by the time I got out there is was melting.

Once I fixed the seal when I put the radio in, this AC has been great.

 

[sunnyside360]

That's good news. There is hope for those of us with anemic A/C in our 3720 cab tractors. Actually I just tested mine today after getting it back yesterday from the JD dealer who installed a missing isolator and replaced a damaged one. The A/C now works very well.

With A/C set at max cooling and fan at mid position, the vent temp was 57-59 deg while the outside temp was 93 deg on very sunny clear day. That is more than 30 deg temp drop. Temp at center of cab at steering wheel was 70 deg. I'll look for ice on the roof next time.

 

[GreenMtns]

That's good news. There is hope for those of us with anemic A/C in our 3720 cab tractors. Actually I just tested mine today after getting it back yesterday from the JD dealer who installed a missing isolator and replaced a damaged one. The A/C now works very well.

With A/C set at max cooling and fan at mid position, the vent temp was 57-59 deg while the outside temp was 93 deg on very sunny clear day. That is more than 30 deg temp drop. Temp at center of cab at steering wheel was 70 deg. I'll look for ice on the roof next time.

I think that part of the poor cooling problem after the seals have been "fixed" is that the dealers are only replacing the outer seal. There are two seals. The inner one prevents the cold air from flowing to the middle of the roof. That would cause the ice on the roof on a humid day. If you go to the parts page for the roof top you will find the numbers for the two seals and a blowup of the roof parts.

 

[nmu98]

I replaced my own seals and did not replace the inner seal. I would really like to see a picture of where it goes. I have it sitting in the barn... I just hate to mess with a good thing...

 

[sunnyside360]

I think that part of the poor cooling problem after the seals have been "fixed" is that the dealers are only replacing the outer seal. There are two seals. The inner one prevents the cold air from flowing to the middle of the roof. That would cause the ice on the roof on a humid day. If you go to the parts page for the roof top you will find the numbers for the two seals and a blowup of the roof parts.

Per the parts diagram, isolator #10 was broken at both rear corners (approx 4 inches each side) allowing outside ambient air to come in and mix with cooled air. Also, isolator #11 in the center was completely missing. A/C is much improved with new isolators.
I suspect (and hoping) the heat in the cab will be much improved for winter use also.

 

[Willl]

You really don't want to see ice anywhere in an A/C system. Refrigeration yes, A/C no.

Too cold of a evaporator will not remove humidity. It'll just freeze on the coil and create air restriction and lower coil temp even more, then you have a snowball effect, literally.

I'd be checking for an air flow restriction across your evap coil.

 

[Nuru]

I was out taking care of a few tall weeds that grew up around the cedars with my 2 year old son. The first issue was that he got too cold with the A/C on level 2... Had to turn it down.

Then he went in and I turned it up a bit. I was in the field for 30 minutes total. I would see a drip on the window ever so often. I stopped to put everything away, and I get out to see ICE, yes ICE on the roof. I ran in to get the camera, and by the time I got out there is was melting.

Once I fixed the seal when I put the radio in, this AC has been great.

now that is scary! Pretty cold.

 

[Nuru]

I received my seals and I am gonna wait a bit and see of my repairs hold a while, then in a few weeks, I am gonna go for it and also potentially change the speakers over to another set I purchased. The JDs were okay when i started but then they got weaker!

 

[nmu98]

You really don't want to see ice anywhere in an A/C system. Refrigeration yes, A/C no.

Too cold of a evaporator will not remove humidity. It'll just freeze on the coil and create air restriction and lower coil temp even more, then you have a snowball effect, literally.

I'd be checking for an air flow restriction across your evap coil.

..

I just might have a dirty rear filter. When reading this, you reminded me that I did not clean the filter after the last bush hog trip. but the air was flowing good, and it was a humid day.

If you look at the places that the water sat on, they are right at the spots the seals touch the top. I would say looking at it, the difference in in temp from that section to the other gathered the water from the air. IMHO, this tells me that the AC is working well. But the ice... well, that might tell me its working too well (somethings wrong)... But, I will say that I am one happy camper with the AC, and reading here, I knew I had to put in my own radio so I had a chance to look at the seals myself.

 

[Spudland_Dave]

On a humid day, mine will "frost up" the rooftop too... The first time I saw water dropping down the outside of the glass I got kinda panicked and hopped out to take a look and was relieved to find it was just condensation.