Tractor air conditioner exit temp ?

LittleD · Jul 6, 2014

I have a New Holland T2420 tractor with cab. What can I realistically expect for cool temperature coming from the air conditioner ducts.
Checked recently on an 85 degree day and the exit temp from the ducts was 68 degrees.
Dealer said that's about normal.
On a 90 degree day I won't be able to stand the heat in the cab.
Thanks, Rich

Stuart · Jul 6, 2014

I checked on a few of our tractors and trucks. I can get 40 degree air out of them.

gmccool · Jul 6, 2014

You should be in the low 40 range. I would think 40-44 would be good. Do you have a manual shut off for your heater. Being 68 it sounds like you have warm coolant running thru your heater hoses causing your AC to not keep up.

David G · Jul 6, 2014

That sounds real warm, I would also expect upper 40s.

LittleD · Jul 6, 2014

(quoted from post at 19:15:25 07/06/14) You should be in the low 40 range. I would think 40-44 would be good. Do you have a manual shut off for your heater. Being 68 it sounds like you have warm coolant running thru your heater hoses causing your AC to not keep up.

Yes it has the manual shut off valve and it is turned off.

kevinecwi · Jul 6, 2014

Humidity can be a big factor. If humidity was high
during your test 20° difference out the vents would
be considered ok. Does the system have a "max" or
recirculate setting? That would keep the system from
pulling outside air.

Allan in NE · Jul 6, 2014

He's telling you that it's normal for the air conditioning not to be working?....That's odd.

Allan

LittleD · Jul 6, 2014

Allan, Exactly what I was thinking...and this is after they came out and installed a new compressor. Will be calling them in the morning and will have a good discussion.

LittleD · Jul 6, 2014

kevinecwi.....The system does not to my knowledge have a "recirculate setting"
If on high humidity days I can only expect a 20 degree drop ...then on a 95 degree day it can't cool the cab with all the glass around it.
It's not designed to run with the doors open and with the trans/rear end heat it will be 85 ~ 90 degrees in the cab.
Thanks , Rich

Sprint 6 · Jul 6, 2014

Bare minimum rule of thumb I use is 30 degree drop from
ambient. Good running system should drop forty unless
the humidy is really high. Make sure your condenser is
clean and the fan is pulling lots of air. Run engine at about
12-1500 rpm and feel the condensenr inlet and outlet, inlet
should be too hot to hold and the outlet should be much
cooler. If both are hot, condenser is not clean enough to
work properly. If it has just been worked on, I would
suspect it is under charged or has air in it.

jimg.allentown · Jul 6, 2014

Normal should be around low 40s for discharge temperature at the outlets. There are all sorts of "rules of thumb" that sometimes apply, and sometimes not. 68 degree air on an 85 degree day is simply not acceptable.

Causes can be many......

First, if there is air in the system, it will simply NOT work efficiently. Air is a non-condensable gas, and cuts efficiency drastically.

Second, level of charge. If the system is over or under charged, the system again will not work correctly.

Third, if there is TOO MUCH OIL in the system, it also reduces the efficiency of the unit.

I suggest putting a set of gauges on it, and checking the readings. On an 85 degree day, the high side should be 250 to 350 psi. The low side should be in the 30 to 40 psi range.

If gauge readings are about right, then it is time to empty the system with a refrigerant recovery machine. This will get the oil out as well as the refrigerant. Next, evacuate the system and add the correct oil charge followed by the correct refrigerant charge.

Keep in mind that if the gauge readings are not within the correct ranges, it is likely that there is another problem with the system.

JD Seller · Jul 6, 2014

LittleD: Something to think about is that the systems on the smaller tractors can struggle to keep the cab area cool. I have ran into this on the JD 5000 series cabs. The area in the condenser and evaporator is smaller than on the larger tractors. IT is even worse on your NH 2420 in that you do not have an isolated cab. So you will get heat off of the drive line.

Make sure that the evaporator and condenser are completely clean. I use compressed air and a garden hose to clean them. I never use high pressure water. You can damage them.

You should see a 40-50 degree drop across the evaporator if everything is working well.

Check and make sure the heater core is actually cool. I have had controls leak a small amount through the control valve an it take very little to make the AC not work well.

Steve@Advance · Jul 6, 2014

Is this a new tractor? Has it always been this
way? If so, something may have been assembled
wrong or there is a blockage. You say the
compressor was replaced, wonder if it was really
bad or just a guess. If it was bad, the
filter/accumulator/orifice tube should have been
replaced and the system vacuumed down. There could
still be contamination in the system from the
failed compressor.

Since they've already looked at it, I would guess
it's under warranty or at least the repair will be
covered. I would want to see some gauge readings
before they start throwing more parts at it,
especially if I were paying for them!

http://www.aa1car.com/library/ac98.htm

Super-H-Mike · Jul 6, 2014

Rule of thumb is if it cannot get 50 or below on a
hot humid day, customer will not be comfortable and
will complain, that is for cars.

jm. · Jul 6, 2014

Over the last 20 years I have seen the answer to this question change quite a bit. For years folks thought discharge around 45 to 50 deg was acceptable but in the latter model units manufactures have gone to using larger blower motors and moving more air but not as cold. Now days most new tractors are considered acceptable if discharge air is 30 degrees lower than the outside air. On a 90 degree day that is cutting it close with all the glass they have in the new cabs.

LittleD · Jul 6, 2014

(quoted from post at 20:27:55 07/06/14) Is this a new tractor? Has it always been this
way? If so, something may have been assembled
wrong or there is a blockage. You say the
compressor was replaced, wonder if it was really
bad or just a guess. If it was bad, the
filter/accumulator/orifice tube should have been
replaced and the system vacuumed down. There could
still be contamination in the system from the
failed compressor.

Since they've already looked at it, I would guess
it's under warranty or at least the repair will be
covered. I would want to see some gauge readings
before they start throwing more parts at it,
especially if I were paying for them!

http://www.aa1car.com/library/ac98.htm

Steve, I purchased this tractor "2008 model" used (1200 hrs.) this winter from an estate auction "91yr old" and used it to plow the snow from the driveway. Don't know the history of the tractor but it looks new.

LittleD · Jul 6, 2014

JD Seller.....I think you may be on to something regarding the small sized tractors having cooling issues...as I have heard something to that effect before.
This is my first tractor with Cab Heat/Air and I had visions of cool operating comfort....but it maybe wishful thinking.
Rich

notjustair · Jul 6, 2014

I'm not as impressed with the newer tractors, but the cabs are
a lot bigger. The a/c in the 4440 will make you cold with the fan
on low on a 95 degree day. Cold enough to turn the temp
control up. The 7800 has to run on medium fas speed to be
nice and cool. The cab is lots bigger and lots more glass. It
sounds like the dealer is feeding you a line, though.

the flying belgian · Jul 6, 2014

My tractors don't have a recirculate setting per say
but they have a recirculate vent that you slide open
or shut to draw air from outside or recirculate
inside air. This is in a Caseih cab. The combine
cab has the same thing.

jeffcat · Jul 6, 2014

Older equipment used R-12. New stuff is 134-A. R-12 would get a lot colder and 30* was a very normal differance. 134 may do it on a system designed for it but not an older converted system. See how cold the freezer in your fridge can keep ice cream. Now it is Zero. Used to be -10 or 15. You are going to get at least a hundred opinins but both of my neighbors do AC and I work with several HVAC guys at work. The older R-12 and 502 and such worked better. Thank the enviro clowns. REAL refrigeration uses Amonnia. That stuff gets REALLY cold. It will also kill ya.

IH2444 · Jul 6, 2014

Jeff, the tractor in question is a 2008. It would be designed for 134A.

I think something is not right with the AC. However I would have to see the gauge readings and such to be able to decide what the trouble is.
My first thought would be not enough gas in it. But again I would have to see the readings to make a call.

kevinecwi · Jul 6, 2014

Should the system blow colder air? Maybe so, but
with a marginal system everything needs to be right.
For example, if the condenser on my 6105 white
becomes the least bit restricted it is noticeable in the
cab real quick. Blow out the fins and everything is
fine again.
I've always felt farm tractor cabs are harder for an
A/C system to keep cool,
1. Too much glass
2. Dusty/dirty work environment
3. Tractors have plenty of other
sources of heat.

showcrop · Jul 7, 2014

I just had the AC in my 21 year old Ford serviced this spring. I didn't check the temp but after an hour or so in 85 degrees I was turning the knob down to half.

ASEguy · Jul 7, 2014

68 degrees isn't what I consider to be normal. Center duct temp on low fan should be around 40-45 degrees after the duct cools down. I just repaired the A/C on a family friends John Deere. The low side line was cool, pressures were good. I found a plugged cabin air filter in the roof. His blew warm air also.

Greg_Ky · Jul 7, 2014

If they replaced the compressor it probably needs the
condenser and drier replaced also, they get fouled with the
ground up pieces from the compressor. If charged on the low
side 40* outlet air and at spec. Charge 50* outlet has been my
experience with clean condenser, evaporator, and cab filter.

JMOR · Jul 7, 2014

(quoted from post at 19:58:41 07/06/14) I have a New Holland T2420 tractor with cab. What can I realistically expect for cool temperature coming from the air conditioner ducts.
Checked recently on an 85 degree day and the exit temp from the ducts was 68 degrees.
Dealer said that's about normal.
On a 90 degree day I won't be able to stand the heat in the cab.
Thanks, Rich

ost of the responses seem to address outlet temperature for a particular daytime ambient temperature situation. I believe that is not the indicator of a properly operating system. The "indicator" is the DIFFERENCE between evaporator inlet air temp & evap outlet temp....the evaporator drop or delta T.

Tractor air conditioner exit temp ?

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