A/C Temperature?

[trook]

For those of you with cabs, what is the temperature of the air coming out of your a/c vents? My new JD 5075e is only blowing 70 degrees. When I advised my dealer something was wrong with the a/c, they checked it and said it is "cooling". It is comfortable in the cab with the fan on 1 or 2, but the outside temp is only 75. They said nothing is wrong with it. The return line is cold and wet, but I can't help but think the temp should be MUCH cooler. What's going to happen with the outside temp reaches 95 degrees???

For comparison purposes, the air temperature in my truck and wife's car is around 42 degrees.

 

[tony Cecil]

I`m having the same problem, same explanation , so I think the truck is right and in my case the little valve looking thing is white with frozen vapor, so I think something is wrong there...Good Luck Tony

 

[trook]

What make and model tractor do you have?

 

[jd110]

RUle of thumb I was taught; temperature from vents should be AT LEAST 30 degrees cooler than outside air temperature. Are you sure the heater valve is closing completely? Try feeling the heater hoses where they enter the cab. If they are warm, try pinching one closed with a clamp and see if the temperature in the cab improves. Also be sure the radiator and condenser is clean. Even if it appears clean, dirt can be in the fins and not visible. Place your hand in front of the radiator with engine running half throttle or faster, you should feel a strong flow of air being drawn through the radiator.

 

[grsthegreat]

hmmm, im not sure if the problem isnt associated with the fact that the outside temp is so cool already. Ive never run mine in the winter except far a few times when the condensation in the cab was an issue. Ive since fixed that issue with opening the outside air vent in winter while running the heater.

I can tell you that in the summer, while its 97F outside the interior of my cab is darn right chilly. Ive never checked it with a thermometer, but i do have to turn fan to lowest setting or i get chilled. It SUCKS when i have to leave the cab.

If i think about it tomorrow, ill see what mine does , however its only supposed to get to 49F tomorrow, so it may be too cold to tell.

 

[jenkinsph]

I would expect to see about 45 degree air at the vents with 75 degree ambient temperature. If your tractor is putting out 70 degrees at the vents you have a problem. The first things I would check are the front condenser and the evaporator in the roof, make sure both are real clean.

I would also add that most AC systems will cool the evaporator coil down to a cut off temperature around 40 degrees, this is to prevent the coils from freezing up. In this set up the air blowing over the evaporator coil can't get much lower than 45 degrees. When the cab is hot after being parked in the sun it will have to cool down gradually so the air temperature at the outlets may be close to 60 degrees but should continue to fall as the air temperature lowers and the air is exchanged.

 

[trook]

Guys, I should have added that this is a brand new tractor. I have done about 2-3 hours worth of work. The radiator and condenser are spotless.

I had the dealer check the a/c last week because the air was cool but not cold when I received the tractor. He said it was "cooling" and normal. I don't dare open the roof as I have heard stories about tearing a seal. I checked the temp coming out of the vents this afternoon on a 75 degree day. The vent temp was no better than 70 degrees, sometimes a little warmer.

grsthegreat, I have heard something similar to what you are saying about the ac not working well until the outside temp rises a little. However, auto ac's seem to work very well with 70 degree temps. Are tractor ac's different?

 

[grsthegreat]

dont know. Ive never run an air cond till it gets into high 80 myself.

Im pretty sure my a/c wont work very well with 49F outdoor temps, but ill check it out tomorrow.

 

[grsthegreat]

i would think there no different than auto a/c units. i mean, how much different can they be. there both just basic automobile units.

 

[jenkinsph]

Guys, I should have added that this is a brand new tractor. I have done about 2-3 hours worth of work. The radiator and condenser are spotless.

I had the dealer check the a/c last week because the air was cool but not cold when I received the tractor. He said it was "cooling" and normal. I don't dare open the roof as I have heard stories about tearing a seal. I checked the temp coming out of the vents this afternoon on a 75 degree day. The vent temp was no better than 70 degrees, sometimes a little warmer.

grsthegreat, I have heard something similar to what you are saying about the ac not working well until the outside temp rises a little. However, auto ac's seem to work very well with 70 degree temps. Are tractor ac's different?

How long did you run the AC before checking the temperature at the outlets?

 

[trook]

I checked it multiple times today from 1 minute after running the ac to 30 minutes after running the ac at low rpms and high rpms.

 

[puckgrinder85]

One would think it would be a little cooler then that, but comparing it to an auto may bias your look on how it may perform. I would wait for a day you can really use it and see how it performs. It is a tractor and the system capacity may not be that huge. Pulling the moisture out of the air and dropping it 10-20 degrees may be all it can do, and maybe you'll find that's all you need to be comfortable. I don't think I ever run the a/c in my truck full blast other than just starting up from a hot soak in the sun, otherwise way too cold. Also if the machine has recirculation capability that will help cool the cab faster.

 

[jenkinsph]

I checked it multiple times today from 1 minute after running the ac to 30 minutes after running the ac at low rpms and high rpms.

I was checking the temperatures in Jackson before replying and it looks like you will need this to work within 6 weeks. Your dealer will be busy by then, I would force the issue with the dealer now. Let him know you are not happy with it and know the AC isn't working properly. Make sure the blue dial is turned on fully and the red dial is turned off fully first. I am an AC contractor so familiar with this.

 

[puckgrinder85]

Would be easy just to verify the correct charge amount, that's 90% of the issues we encounter is leaks.

 

[trook]

jenkinsph, yes, I agree. That is why I had the dealer pick up the tractor already to look at the issue. I was puzzled when he told me it was working properly. Yes, the blue dial is turned on fully and the red dial is turned off fully. The compressor toggle is also turned on.

puckgrinder85, I don't have a way to check the charge amount. I certainly hope the dealer checked that when they had the tractor last week. The return line next to the engine is cold and is covered with condensation. I've always heard that is the rule of thumb to determine whether or not the freon level is correct. However, for some reason, the air blowing out of the vents is no colder than 70 degrees.

 

[94BULLITT]

Anything below 50* is acceptable in a car with the blower on low.

 

[jenkinsph]

As jd110 mentioned earlier the heater may be circulating and warming the air too. It would have helped the troubleshooting process to know what the temperature was with the compressor switch off. High temperature outlet air with the heater dial turned down would indicate a leak through the valve.

Condensation on the return line is normal, icing up is not.

 

[trook]

I checked the air with the compressor switch off. It was about 85+

 

[jenkinsph]

trook,
jd110 is a Deere mechanic who always seems to offer top notch advice.

Since the temperature was at least 10 degrees over ambient it sounds like this is your problem. Might mention this to the dealer that you suspect the hot water mixing valve is not closing fully.

 

[MHarryE]

It's been a long time since I've been involved with cabs and air conditioners but in the older days before being able to dial in a temperature it was in the mis 40's at the outlet which matches what most are saying here. My tractors are all in the 40 range except on really cold days when I just want to dehumidify the cab - we are talking zero or so. Then the AC shuts down and I only get hot, humid air, foggy windows, and sweat dripping into my eyes.