AC/Heat issues

[fruitcakesa]

Occasionally when I push the AC button and turn on the fan, it blows hot air.
Obviously something is wrong.
I have heard of a stuck heater valve but don't know where or how to check it.
My M has all the ac/heat stuff under the seat.
Any ideas?

 

[85Hokie]

How long does it blow hot air ? Continuously more than a minute ?

 

[Dave_eng]

Read your Owners' manual. It will explain how their is a refrigerant sight glass near the front of the tractor which shows if you have enough refrigerant for the system to work properly.

You also need to see if the electric clutch on the AC compressor is engaging. It wont if you have low refrigerant because of a leak.

The heater valve story is a bit exaggerated. Far more likely you have a leak.

Dave

 

[fruitcakesa]

How long does it blow hot air ? Continuously more than a minute ?

Yes.

 

[fruitcakesa]

Read your Owners' manual. It will explain how their is a refrigerant sight glass near the front of the tractor which shows if you have enough refrigerant for the system to work properly.

You also need to see if the electric clutch on the AC compressor is engaging. It wont if you have low refrigerant because of a leak.

The heater valve story is a bit exaggerated. Far more likely you have a leak.

Dave

I will check these things, thanks

 

[Jim L.]

It could be any of the things already mentioned.

I would suggest first making sure that the evaporator and condenser are clean (outsides air fins).

The book values for pressures and temperatures are only valid when the components are clean.

 

[kubotafreak]

Simply put, AC= CLOSED SYSTEM (should be no escaped fluids/gasses)

Like Dave said, check front of clutch coil for lockup(rotation)

Then look for condition of sight glass if clutch is spinning.

If the clutch isn't spinning, the fix is to look for any sign of ac oil on joints, fittings, coils, and system pressure. Repair the leak first , add oil, and then pull vacuum, recharge. No real way around this process. Im actually 609 certified if you have charging questions.

You more than likely have a low condition(you said occasionally), which is easy to have, since these tractor systems hold very little compared to some on the road vehicles.

 

[fruitcakesa]

Simply put, AC= CLOSED SYSTEM (should be no escaped fluids/gasses)

Like Dave said, check front of clutch coil for lockup(rotation)

Then look for condition of sight glass if clutch is spinning.

If the clutch isn't spinning, the fix is to look for any sign of ac oil on joints, fittings, coils, and system pressure. Repair the leak first , add oil, and then pull vacuum, recharge. No real way around this process. Im actually 609 certified if you have charging questions.

You more than likely have a low condition(you said occasionally), which is easy to have, since these tractor systems hold very little compared to some on the road vehicles.

Finally got around to looking under the hood:
Small bubbles appear to circulating in the sight glass and the clutch looks like it is engaged.
Blew cold for a few seconds erratically and then blew hot.

 

[DustyRusty]

bubbles in the sight glass indicate an undercharge. You should see a thin stream, like a thread when fully charged. Probably the compressor cuts out because of low refrigerant level. This is a safety to keep from ruining the compressor.

 

[kubotafreak]

You need to confirm low side pressures after the compressor kicks on is less than 20psig. It will be higher than that before the compressor kicks in. Once it kicks in the pressure should drop and levelize. Granted if it kicks off before it reaches steady state, just post the readings.

 

[fruitcakesa]

You need to confirm low side pressures after the compressor kicks on is less than 20psig. It will be higher than that before the compressor kicks in. Once it kicks in the pressure should drop and levelize. Granted if it kicks off before it reaches steady state, just post the readings.

Thanks for the detail
I have to consider my next step.
I won't take it to the dealer just for this, getting an AC person to come where I live is highly unlikely and I don't have the AC equipment to check on things.

 

[kubotafreak]

Thanks for the detail
I have to consider my next step.
I won't take it to the dealer just for this, getting an AC person to come where I live is highly unlikely and I don't have the AC equipment to check on things.

We can walk you through checking the pressure. You can pick up a cheap can tap at Walmart/Atwood’s. It will have a gauge. The new style cans are valved, so they keep well.

 

[fruitcakesa]

View attachment 60292

We can walk you through checking the pressure. You can pick up a cheap can tap at Walmart/Atwood’s. It will have a gauge. The new style cans are valved, so they keep well.

Thank you
That is an offer I can't refuse.
I will check in when I have the hardware

 

[Orange1forme]

Simply put, AC= CLOSED SYSTEM (should be no escaped fluids/gasses)

To a point, you are correct.
While I have not looked at a tractor specifically, vehicles rely on hoses and o-rings and they deteriorate, especially if not used regularly.
It is best practice to use your vehicle a/c weekly(this includes defrost on newer vehicle) to keep the non-metal parts of the system lubricated/pliable. O-rings will dry out and hoses will dry and crack, both causing a leak.

Can't say this is your case, but most of the time a vehicle a/c leak is found in the hoses, o-rings or their connecting points.

 

[fruitcakesa]

My local Advance auto has the recharge kits in stock, so I will have one in hand tomorrow

 

[dvcochran]

You did not say what model your tractor or the hours.
My M9 had the pushbutton for the A/C go out. The light would not come on when the button was pressed. Sometimes you could jiggle it and get it working.
In a perfect world an A/C system should not loose charge or at least take a very long time to leak out (years/decades). Tractors sometimes live a rough life so that is not a certainty.

Things I would do a close in order:
Clean the condenser and evaporator really, really well. Not just blown out with air.
Replace the Cabin filter.
With the tractor off and preferably cool turn the compressor clutch by hand. It should turn smooth, no catches or hard spots.
Run the tractor at 1,000 to 1,200 rpms and let is run for several minutes.
Observe the compressor clutch and see how it is cycling. On/off rapidly is usually a sign of a low charge. Chatter is usually a sign of a clutch issue.
Check the sight glass looking for bubbles.
If possible put a set of gauges on the system, checking both low and high side pressures.
Very high pressures on either gauge usually indicates a blockage or failing/failed component.
Low pressures may be as easy as the system needing a charge or could be an expansion valve issue. Unless you have at least a modicum of A/C experience I do Not recommend the Walmart charge kit. Good for a patch if you are selling the tractor but can just as easily create more problems. If you have checked the system with gauges and everything looks good they will work but you are stabbing in the dark on how much charge you are putting in most of the time.
You can find A/C pressure charts online; they are dependent on the ambient temperature for the most part but it is not concrete and there is a degree of 'art' to A/C work.

Most of us have been down the trail you are on. If you cannot do the work yourself and do not want to get your dealer involved I see no choice but to either find a mobile mechanic or take it somewhere else. I use a local heavy equipment/diesel shop because they are closer (I can walk the tractor there) and much cheaper.

If you know of an experienced auto mechanic/A/C guy they should be able to do the work, especially if you have the WSM available for them to check charge rates and such.
It would not have to specifically be a tractor mechanic. The main outliers are how much dirtier a tractor system gets and knowing how to clean the condenser/evaporator. Not a hard job but can be tedious.

 

[Tx Jim]

DITTO what dvcochran stated.
I know very little about the EZ-chill hose/gauge BUT if one can't monitor both high & low pressures of the AC system you would be better off if that gauge/hose was still in the retailers inventory. It's common practice for the ill informed about AC systems to over-charge with refrigerant lowering AC system ability to cool.

 

[fruitcakesa]

You did not say what model your tractor or the hours.
My M9 had the pushbutton for the A/C go out. The light would not come on when the button was pressed. Sometimes you could jiggle it and get it working.
In a perfect world an A/C system should not loose charge or at least take a very long time to leak out (years/decades). Tractors sometimes live a rough life so that is not a certainty.

Things I would do a close in order:
Clean the condenser and evaporator really, really well. Not just blown out with air.
Replace the Cabin filter.
With the tractor off and preferably cool turn the compressor clutch by hand. It should turn smooth, no catches or hard spots.
Run the tractor at 1,000 to 1,200 rpms and let is run for several minutes.
Observe the compressor clutch and see how it is cycling. On/off rapidly is usually a sign of a low charge. Chatter is usually a sign of a clutch issue.
Check the sight glass looking for bubbles.
If possible put a set of gauges on the system, checking both low and high side pressures.
Very high pressures on either gauge usually indicates a blockage or failing/failed component.
Low pressures may be as easy as the system needing a charge or could be an expansion valve issue. Unless you have at least a modicum of A/C experience I do Not recommend the Walmart charge kit. Good for a patch if you are selling the tractor but can just as easily create more problems. If you have checked the system with gauges and everything looks good they will work but you are stabbing in the dark on how much charge you are putting in most of the time.
You can find A/C pressure charts online; they are dependent on the ambient temperature for the most part but it is not concrete and there is a degree of 'art' to A/C work.

Most of us have been down the trail you are on. If you cannot do the work yourself and do not want to get your dealer involved I see no choice but to either find a mobile mechanic or take it somewhere else. I use a local heavy equipment/diesel shop because they are closer (I can walk the tractor there) and much cheaper.

If you know of an experienced auto mechanic/A/C guy they should be able to do the work, especially if you have the WSM available for them to check charge rates and such.
It would not have to specifically be a tractor mechanic. The main outliers are how much dirtier a tractor system gets and knowing how to clean the condenser/evaporator. Not a hard job but can be tedious.

2010 M6040 1500 hrs

 

[BAP]

Before worrying about the AC refrigerant levels, make sure that the heater hoses both going to and return from the heater are not getting hot. If they are then the shut off valve is not working properly. If the heater valve is leaking by, the AC will shut down from heating up and messing up the pressures. I have seen that issue on many tractor AC’s over the years. Easiest fix is a shut off valve in the coolant line coming off the engine block.

 

[Tx Jim]

BAP
Very good idea. The coolant flow to the heater core on my JD 4255 has been manually shut off with an aftermarket manually operated valve since 1994. Tractor cab heater is rarely needed during Wintertime in Texas