A/C problem

[Mildthunder]

Hi everyone. My first post here.

Have a 2016 5085E . Recently, the A/C started not cooling. I noticed the compressor clutch is rapidly cycling on and off. At first I thought low charge, but thats not it. The clutch engages and disengages very fast. Like engage for 1 second, disengage for 1 second, repeat. It seems to only do this when its above 85* ambient. Cab filters cleaned and replaced, condenser filter cleaned, all good there.

Any thoughts?

 

[TractorGuy]

Low charge or failing low pressure switch. Have you connected a set of gauges to it?

 

[Mildthunder]

I only had my low psi side gauge , it was showing 45psi compressor on, but once clutch starts going crazy so does the gauge. Sometimes it works fine and the clutch cycles normally and air blows ice cold.

 

[rustyshakelford]

Check for faulty clutch wiring

Brett

 

[TractorGuy]

Try bypassing the low pressure switch with both low and high side gauges connected. You need to keep the clutch engaged with both gauges for starters.

 

[Tx Jim]

I only had my low psi side gauge , it was showing 45psi compressor on, but once clutch starts going crazy so does the gauge. Sometimes it works fine and the clutch cycles normally and air blows ice cold.

One can't diagnose AC problems successfully without utilizing both high & low pressure gauges.

 

[R134a]

Mobile A/C is charged by weight, not pressure.* ....Because weight is a constant. Once you have the correct charge then a set of guages can be used to detect problems. Speculation..... (Rapid cycling is textbook low charge.) You ruled that out how? :confused3:

 

[Tx Jim]

R134A
It difficult for the average shade tree mechanic to measure the refrigerant out in a hay field BUT I've been successful getting my AC systems blowing "cold air" by watching the pressures on both gauges. It may not be correct but it sure beats paying 100's of $$$ for service call/labor & waiting on technician to arrive to measure oz's of refrigerant.

 

[R134a]

I get it. I don't want him to make a mistake and wind up with an expensive headache. He is welcomed to call me & I can walk him through it.

 

[Harry in Ky]

Mobile A/C is charged by weight, not pressure.* ....Because weight is a constant. Once you have the correct charge then a set of guages can be used to detect problems. Speculation..... (Rapid cycling is textbook low charge.) You ruled that out how? :confused3:

Yes, weight may be a constant in the academic sense, but in the field it's a different story. If every system's refrigerant weight REMAINED constant, there would be far fewer problems and much less need for people to work on them. Charging strictly by weight is great in theory, but not always practical in practice.
While I personally have serviced/charged multiple hundreds of tractor A/C systems over the years, both R12 and 134A, I can assure you that the factory recommended "charge weight" spec is NOT always readily available. Even if it were, how does one translate that in a partially charged system as is most commonly found in most cases when a person says his A/C isn't cooling and it's up to you to make it work?
Yes, sometimes mistakes can be costly, but ask a man who's been sweating in a glass box all day if he's willing to "chance" a mistake by someone with a set of gauges, a jug of freon, and a reasonable amount of experience over waiting for someone else to come along who knows all the "theories".

 

[R134a]

What's your plan for dealing with his leak ?

 

[Oldpath05]

Hi everyone. My first post here.

Have a 2016 5085E . Recently, the A/C started not cooling. I noticed the compressor clutch is rapidly cycling on and off. At first I thought low charge, but thats not it. The clutch engages and disengages very fast. Like engage for 1 second, disengage for 1 second, repeat. It seems to only do this when its above 85* ambient. Cab filters cleaned and replaced, condenser filter cleaned, all good there.

Any thoughts?

How come you didn't post your video while your at it................................ok I do it for you, anytime I can give free advertising for tractors companies I'm all in.................... John Deere Quality Pissing ME the F@#% Off! - YouTube <<<<I can understand this guy thrustration, AC lines should not leak for a long time IMO.

 

[Harry in Ky]

I wasn't aware it's been established he actually HAS a leak. So far I thought the main symptom/complaint (other than hot air)was a rapidly cycling compressor clutch. I think there was a post suggesting that may be due to low charge, but I don't see where that's yet been proven. I think there may also be a few electrical possibilities for that and charge level may not even enter in. Been no mention yet of any actual pressure readings or really anything else upon which to base much of a diagnosis.

 

[Tx Jim]

I agree with Harry as I see no leak mentioned by Mildthunder.

 

[Mildthunder]

I agree with Harry as I see no leak mentioned by Mildthunder.

I dont believe this is a low refridgerant situation. Sometimes it works fine all day , others, the compressor cycles rapidly .

When i put the low psi gauge on, while compressor was steady running, it showed 45psi. Once it starts malfunctioning, the low psi reading goes from 45 to near pegging the gauge when compressor shuts off.

Are the low and high psi switches in the headliner? I dont see any visible

 

[Tx Jim]

I dont believe this is a low refridgerant situation. Sometimes it works fine all day , others, the compressor cycles rapidly .

When i put the low psi gauge on, while compressor was steady running, it showed 45psi. Once it starts malfunctioning, the low psi reading goes from 45 to near pegging the gauge when compressor shuts off.

Are the low and high psi switches in the headliner? I dont see any visible

The reason pressure spikes on low pressure gauge when compressor clutch disengages is because pressures equalize when compressor isn't operating.

 

[chevy791979]

The reason pressure spikes on low pressure gauge when compressor clutch disengages is because pressures equalize when compressor isn't operating.

I agree with the pressure rising, but not spiking. When the compressor kicks out, the low side will rise but not spike.

I'm not going to give this much effort without knowing the low and high side pressure. Could be a switch, expansion valve, charge, lack of air flow on condesor/evaporator. I'd also like to know the resistance of the clutch coil. Is the clutch diode good? I've have many diodes fail under amperage load. The doide is on the power side(B+) of the clutch circuit to help with voltage spikes when it disengages

 

[Mildthunder]

Its been working fine this morning. The next time it acts up ill try to take a video of the clutch.

 

[Tx Jim]

I agree with the pressure rising, but not spiking. When the compressor kicks out, the low side will rise but not spike.

Here's a dictionary definition of spike [a sharp increase in the magnitude or concentration of something] I think pressure going from 45 psi to around 125 psi is a sharp increase providing system has adequate refrigerant in system.

If it suits you better I will state low pressure gauge will gradually spike(rise) to where both low & high pressures are the equal while compressor clutch is disengaged

 

[chevy791979]

Here's a dictionary definition of spike [a sharp increase in the magnitude or concentration of something] I think pressure going from 45 psi to around 125 psi is a sharp increase providing system has adequate refrigerant in system.

If it suits you better I will state low pressure gauge will gradually spike(rise) to where both low & high pressures are the equal while compressor clutch is disengaged

Ok, well when I hear spike I think of it going from say, 45 to 125 instantly. When a clutch disengages, the do equalize but it takes a little bit. IMO 45psi on the low side is a bit high. I'm betting the high side pressure is WAY high. Like stated before, we need to know the high side pressure also. Until we know that we are pissing into the wind.