Air conditioning problems

longmeadowfarm · Jul 23, 2018

Re: Air conditioner problem

Tractor: New Holland T4.75 ( 2013 model year)

Given:
Tractor has 1850 hours??give or take
Air conditioner blows very cold air when initially starting up?and working
Air conditioning system was checked for proper refrigerant levels and pressure..all OK per dealer
All 4 air filters are clean and are cleaned regularly..per operators manual.
All four air filters are original.. not changed as per 1200 hr service/replacement interval.?per operators manual.

Operation:
Air conditioner starts out strong and over time the cold air becomes increasingly warmer until it stops blowing cold air.
Air conditioner air flow seems to degrade, along with blowing warmer air.
I shut the compressor off and turn the blower up a notch? this action results in an increasing flow of warm to very cold air for up to 3-5 minutes.
It seems that air flow increases during this ?compressor off? cycle
The cycle of cold/warm/cold air changes from the number 2 to 3 fan setting.
The cycle can be as short as 5-10 minutes in fan position 2 to perhaps a long as 20-25 minutes as was the case yesterday?.in fan position 3.

Additional info
Aa acquaintance of mine told me it would seem to be an air flow problem and to check for a plugged evaporator or duct. As the evaporator and air duct system is ?closed? I doubt it is an airflow
problem associated with a dirty evaporator or a mouse nest in an air duct. BUt it just could be that my filters need changing..

Another friend said it might be a high pressure sensor that?s not turning the compressor off? .. resulting in evaporator ?freezing up?.

The New Holland Dealer told me everything is ok? had the tractor in the shop for some repair work?. and then proceeded to insult me when I asked the service manager to diagnosis the problem
that he couldn?t replicate. Said he wanted to ?vacate? the system and put all new refrigerant back in? I asked why??? .. got some blank stares. I asked if replacing the high pressure sensor was
intrusive.. as some systems have a check valve so as not to lose refrigerant .. et al.. as I said I wanted to do the job myself.. never got back to me.

I took my challenging problem to a Case/IH dealer as they sell the same tractor..just a different color. They looked over the written explanation I submitted and said something like I didn?t know what I
was talking about?.and inferred that the system wouldn?t do that which I reported.

any suggestions ????
Thanks for the help

Tx Jim · Jul 23, 2018

1st thing I'd recommend is installing a manual cut-off valve in heater hose & be positive that it's closed.

JMOR · Jul 23, 2018

(quoted from post at 15:07:12 07/23/18) Re: Air conditioner problem

Tractor: New Holland T4.75 ( 2013 model year)

Given:
Tractor has 1850 hours??give or take
Air conditioner blows very cold air when initially starting up?and working
Air conditioning system was checked for proper refrigerant levels and pressure..all OK per dealer
All 4 air filters are clean and are cleaned regularly..per operators manual.
All four air filters are original.. not changed as per 1200 hr service/replacement interval.?per operators manual.

Operation:
Air conditioner starts out strong and over time the cold air becomes increasingly warmer until it stops blowing cold air.
Air conditioner air flow seems to degrade, along with blowing warmer air.
I shut the compressor off and turn the blower up a notch? this action results in an increasing flow of warm to very cold air for up to 3-5 minutes.
It seems that air flow increases during this ?compressor off? cycle
The cycle of cold/warm/cold air changes from the number 2 to 3 fan setting.
The cycle can be as short as 5-10 minutes in fan position 2 to perhaps a long as 20-25 minutes as was the case yesterday?.in fan position 3.

Additional info
Aa acquaintance of mine told me it would seem to be an air flow problem and to check for a plugged evaporator or duct. As the evaporator and air duct system is ?closed? I doubt it is an airflow
problem associated with a dirty evaporator or a mouse nest in an air duct. BUt it just could be that my filters need changing..

Another friend said it might be a high pressure sensor that?s not turning the compressor off? .. resulting in evaporator ?freezing up?.

The New Holland Dealer told me everything is ok? had the tractor in the shop for some repair work?. and then proceeded to insult me when I asked the service manager to diagnosis the problem
that he couldn?t replicate. Said he wanted to ?vacate? the system and put all new refrigerant back in? I asked why??? .. got some blank stares. I asked if replacing the high pressure sensor was
intrusive.. as some systems have a check valve so as not to lose refrigerant .. et al.. as I said I wanted to do the job myself.. never got back to me.

I took my challenging problem to a Case/IH dealer as they sell the same tractor..just a different color. They looked over the written explanation I submitted and said something like I didn?t know what I
was talking about?.and inferred that the system wouldn?t do that which I reported.

any suggestions ????
Thanks for the help

ow refrigerant charge will yield symptoms that you describe, where evaporator ices over, air flow diminished, then you stop compressor, run blower on high and get cooling and more air flow as ice melts, then resume compressor operation & have good cooling until it ices over again. Same can be caused by too little air flow. Most compressors that I see , cycle on low pressure switch, not high pressure switch.

mite-help · Jul 23, 2018

x2 on heater shut-off. tough one to guess--may be necessary to hook up a gauges @ route them up where you
can read them while in use, if possible

Steve@Advance · Jul 23, 2018

Sounds like it's icing up.

Don't know what system that is, probably an orifice tube and a cycling switch.

If the cycling switch is defective it will ice up. Should be a switch screwed into a port by the evaporator, near or in the accumulator. Sometimes the tech will jumper the switch during charging, may have forgot to remove the jumper. Switch should have a Schroeder valve behind it.

Or it may have an expansion valve, which could be stuck open.

Glen SW Wi · Jul 23, 2018

Could be the heat sensor switch in the evaporator. Ford has had a lot of trouble with them in their vehicles. My AC is acting up like you describe. Took it to the dealer and was informed that I need a whole new AC system for $1800 to @2000. When I drove the 60 miles to the dealer to have it checked it worked perfectly. They will never convince me that a plugged AC will work well enough for 60 miles. Went on the internet and saw that Ford has had a lot of complaints on this. Since 2009. They won't do anything because it is not safety related and the Feds won't make them do the repair. Since the idiot engineers decided to put this serviceable item up under the dash and it can't be replaced without removing the dash it can be an expensive repair. A new sensor cost about $20 but the flat rate book for replacing the unit is 6 or 7 hours of labor. On the 2013 Escape and later the sensor is in the firewall just above the gas pedal and can be replaced in about ten minutes. There is a work around for overcoming the problem on the web which uses a resister. Not perfect, but can be done by most anybody in a few minutes. Winter will be here in WI before long and I won't need the AC until next summer.

farmer656 · Jul 23, 2018

sounds like the Freon is a tad low,, evaporator is freezing up, causing air flow to be restricted, next time this happens , shut of compressor, leave fan running for about 10 minutes turn compressor back on and if it cools wala problem solved

jimg.allentown · Jul 23, 2018

The two most likely things that come to mind for me are evaporator icing and expansion valve.
If the evaporator is icing up, there are a couple of things that can cause it. Undercharged system, cycling switch, and restriction in the air flow are most common ones.
Expansion valve could be a problem if it has one. Some systems use an expansion valve, some use a fixed orifice tube. Your symptoms do mimic a bad expansion valve. Expansion valves are hard to diagnose. They show good readings on the gauges, but the system will not reliably work efficiently. Orifice tubes, on the other hand, tend not to give problems like you describe. They either work or not. Nothing in between.

grizz02 · Jul 23, 2018

like has been said it is icing up the a/c pump more then likely is not cycling on and off had a Kenworth do that soild block of ice around the evaporator air can not get though to blow cold so when you turn it off the ice melts (CHECK YOUR DRAIN TUBE HAS WATER COMING OUT)

dcarp · Jul 23, 2018

X 2 on the evaporator icing up. My Dodge does that same thing, I just shut off the compressor, leave the fan on, and it will defrost in 2-4 minutes. Then I can turn the compressor back on for about 15 minutes the repeat.
If you have the roof access panel, you can check the evaporator quickly, 4 screws and the panel is off.

jtwat · Jul 23, 2018

For the evap to freeze up, the Freon would have to be low. I think you may have a blend door issue. They can be electrically or vacuum operated.
Either one can slowly open and allow heat from the heater core to mix with cool air or close and stop air flow from evap..

farmer656 · Jul 23, 2018

would you open email I have a question please

jimg.allentown · Jul 23, 2018

email is open, but fair to warn you that I get a LOT of spam in my email. As a result, I only check it once or twice a week.

JD Seller · Jul 23, 2018

Well I will wade in. LOL I think your are having an air flow issue. The evaporator is icing up. The reason it will cycle/run longer on the higher fan speed is the additional flow of warm air keeps it form freezing for a longer period. I would say that if you have had it to two dealerships they more than likely checked the Freon pressures and they should be correct.

So that would leave two common things to look for.

1) Just because your duct and evaporator are closed does not mean they can not be plugs/restricted by some thing. Real common one is for the evaporator drain to quit draining correctly and dust blending with water and filling the evaporator with mud/dust.

2) The evaporator drain not work even with clean ducts will back up on the evaporator and then it will freeze into ice and block the air flow.

I would make sure none of these two things are happening before I would look at a high pressure switch not working.

As for replacing the high pressure switch. You usually need to evacuate the system to do that on most systems.

There is a dead simple way to check for this. unplug the AC compressor. Makes yourself a pig tail with a switch in it. This needs to be long enough to reach the cab. You want the factory harness to feed your short harness and then your harness hooked to the compressor. This way you can turn off the power to the compressor. Run the tractor. At the first sign of you losing cold air turn the compressor off. If it the air gets colder for a while and then warms up then the compressor back on. If the cycle repeats then your system is not shutting the compressor off when it should. THIS IS ONLY true if the ducts/evaporator are clean AND the system is filled to the proper level of Freon.

P.S. The one dealership had a good idea and just did not tell you why. The only true way to 100% know if the system has the correct Freon level is to pump it all out and put the exact amount of Freon back in. Some systems are real sensitive to this. A few ounces low or high can cause the type of trouble your having.

sotxbill · Jul 24, 2018

either low freon, or its very humid and your running fan too low to blow off the condensation.... are common causes.

restricted air flow on the coil, again, not removing the condensation,,

blocked off drain, filling coils with water.

common solutions.

check freon level and add a bit if low.
make sure air flow is not restricted. and drain is open
use "recirculate" to avoid drawing in more humid outside air if humidity outside is high.
run higher(t) fan speed across coil to blow off condensation and keep coil from freezing..
set temp control "warmer" setting initially, to cycle off the compressor more often to let the coils cool a bit, dry a bit, cool a bit as it cycles. After inside air is dehumidified, lower temp setting gradually, all why keep on recycled air at high blower speed. Over time the cab will dry, and the system will functionin a more normal mode a lower fan speeds.

Air conditioning problems

longmeadowfarm

Member

Tx Jim

Well-known Member

JMOR

Well-known Member

mite-help

Member

Steve@Advance

Well-known Member

Glen SW Wi

Member

farmer656

Member

jimg.allentown

Well-known Member

grizz02

Well-known Member

dcarp

Well-known Member

jtwat

Member

farmer656

Member

jimg.allentown

Well-known Member

JD Seller

Well-known Member

sotxbill

Well-known Member

Similar threads