B3000 A/C Re-Charge help

[TimP]

Hi All.

MY A/C isn't getting as cold as it used to and I took a look at the sight glass and saw it started out with a very bubbly stream and then went to clear, as in no fluid as far as I can see.

I have ordered some cans of 134A Freon and a decent set of manifold gauges.

But, once I get it all, not positive the procedure to add a charge to the system.

What are the pressure reading I should be looking for when I add the 134a on my system?

Do I just hook up the quick connects to the Low and High pressure fittings and add the freon until I get the proper pressure?

Thanks for the help.

 

[5030]

Hi All.

MY A/C isn't getting as col das it used to and I took a look at the sight glass and saw it started out with a very bubbly stream and then went to clear, as in no fluid as far as I can see.

I have ordered some cans of 134A Freon and a decent set of manifold gauges.

But, once I get it all, not positive the procedure to add a charge to the system.

What are the pressure reading I should be looking for when I add the 134a on my system?

Do I just hook up the quick connects to the Low and High pressure fittings and add the freon until I get the proper pressure?

Thanks for the help.

Follow the instructions on the gauge kit and 134A can. Far as charging a low system, you need around 150 psi on the high side with the compressor running and the ac on high, full cold. With the compressor energized, you should see a solid whitish stream of 134 in the sight glass.

Be apprised however that usually, poor cooling isn't the freon level but a dirty cab condensor. Have you cleaned it lately. I clean mine yearly. The cab mounted filter works but dirt will still get in and clog the cab condensor. I'd clean the system first and fiddle with the freon second.

 

[5030]

Don't add oil either if you do add refrigerant. The oil in Kubota's PAG 46 will remain in the system whether it's low on refrigerant or not. Resist the temptation to add oil unless you replace a component. The oil will be adhered to all the system components inside them.

Like I said, first clean all the heat exchangers, under the hood and in the cab before fiddling with refrigerant.

I've heard many people say that the Kubota climate control is marginal at best. I disagree. Mine will freeze you out no matter how hot it is outside, even on a 95 degree day, I cannot advance the blower setting past 1. However my HX's are clean and I keep them clean. Finally, if you do add refrigerant, do not add refrigerant with sealer in it, just straight no additive freon 134. The sealant can gum up the works. If you suspect a leak then pull the system down with a vacuum pump and let it stand for an hour with the vacuum on it. If the gauge don't move you should be ok. If it does, it's time to buy a leak detector, charge the system and find the leak and repair it. Most times systems will leak from the Schrader valves (where you inject freon) and check the pressures. If a Schrader valve is leaking, usually a quick release of refrigerant with a small flat blade screwdriver will clear the valve and restore the seal. Wear gloves and eye protection at all times. Refrigerant in your eyes will blind you and contact with bare skin will cause immediate frostbiite. If the system apperas to hold vacuum for an hour but slowly looses the charge, the addition of a fluorescent die will pinpoint the leak as well.

Refrigeration isn't all that complex but overcharging any system can cause serious consequences. You can destroy the compressor or rupture a refrigerant line. Mine does super at 150 on the high side. Yours may or may not. Only way to really tell is a thermometer in a a vent and note the temperature differential between ambient and refrigerated.

 

[5030]

:thumbsup:



What you're probably seeing is a flow of liquid freon when the bubbles disappear, especially if your suction line is getting cold. Low side pressure is usually around 35-40 and high side is closer to 200 psi. If you're getting rapid cycling, then you may be low on freon. Otherwise, clean your condenser and evaporator coils first and check filters.

You really cannot see 134a. It's essentially clear to a milky white color depending on the brand. I've read comments where people say they can see the oil too. That is BS. PAG46 is almost clear. Unless you have X-ray vision you won't see it and the only way to check the oil is with the cotton ball test.

 

[TimP]

THANK YOU ALL for the help, tips and guidance.

Sounds like I need to clean the components and see if it makes a difference. I have had my B3000 for about 1 -1/2 years and have not cleaned the evaporator.

I have no idea if it was ever cleaned in the past.

Unfortunately, I have to remove the roof to get at the evaporator.

Not sure what I need to remove to get the roof off. I'll look at the parts diagram to see if it shows what screws/bolts need to come out.

The cab fresh air filter was replaced last Feb.

If the 134a is clear and I can't really see it, how can I tell if I am low, or just can't see the liquid thru the sight glass?

 

[Snappy BX]

As one had said, if your compressor is cycling rapidly, then you are probably low on Freon. With the system off, your gauge set should read approx. ambient temp, example - 70 degree day, 70 psi on both sides of gauge with system off.
When tractor is started and system on, low side should be 32-40 high side 150-225 depending on temp of day and airflow over condenser.
NEVER, EVER open High side gauge with tractor running and system on especially if you are trying to recharge the system. The pressure in the high side will exceed the pressure in the can possibly causing injury or death.. Finally if you system is low you have a leak, find the wet spot. That's where the oil in the system has left a wet spot and the dirt adheres to it.
If the system does have a leak, it should be repaired, evacuated (with a vacuum pump) and recharged with the correct amount of Freon.
Sorry for the long winded answer, hope it helps and good luck.

 

[RickB]

We should be using the correct terminology to avoid confusion. The condenser coil is in front of the engine fan, the evaporator coil is stacked with the heater coil in the cab roof.

 

[RickB]

As one had said, if your compressor is cycling rapidly, then you are probably low on Freon. With the system off, your gauge set should read approx. ambient temp, example - 70 degree day, 70 psi on both sides of gauge with system off.
When tractor is started and system on, low side should be 32-40 high side 150-225 depending on temp of day and airflow over condenser.
NEVER, EVER open High side gauge with tractor running and system on especially if you are trying to recharge the system. The pressure in the high side will exceed the pressure in the can possibly causing injury or death.. Finally if you system is low you have a leak, find the wet spot. That's where the oil in the system has left a wet spot and the dirt adheres to it.
If the system does have a leak, it should be repaired, evacuated (with a vacuum pump) and recharged with the correct amount of Freon.
Sorry for the long winded answer, hope it helps and good luck.

Good advise.

 

[5030]

We should be using the correct terminology to avoid confusion. The condenser coil is in front of the engine fan, the evaporator coil is stacked with the heater coil in the cab roof.

Thank you Rick. One is in front and the other is buried.....

 

[TimP]

We should be using the correct terminology to avoid confusion. The condenser coil is in front of the engine fan, the evaporator coil is stacked with the heater coil in the cab roof.

Thanks... I'll correct my previous post. I always get them confused.... :.(

 

[5030]

THANK YOU ALL for the help, tips and guidance.

Sounds like I need to clean the components and see if it makes a difference. I have had my B3000 for about 1 -1/2 years and have not cleaned the A/C parts in the roof (condenser?). I have no idea if it was ever cleaned in the past.

Unfortunately, I have to remove the roof to get at the condenser.

Not sure what I need to remove to get the roof off. I'll look at the parts diagram to see if it shows what screws/bolts need to come out.

The cab fresh air filter was replaced last Feb.

If the 134a is clear and I can't really see it, how can I tell if I am low, or just can't see the liquid thru the sight glass?

If yours is like mine (and I presume it it), inside the cab, if you look up, there will be a number of Phillips head screws around the edge of the inner headliner. Every other one needs to be removed to remove the roof Problem is, which every other one.....

Simple. Remove one. If it's long it's a roof screw. If it's short, it's a headliner screw. All the long ones have to be removed to get the roof off. In my case, it's 10 screws. Yours may be different.

Cleaning the evaporator is a real pizzer. Lots of stuff up there (depending on what options you have), I have all of them. if your unit is like mine, you won't be able to completely remove the upper shroud without removing the heater core and on mine at least, the heater core is hard piped so what I did was take out all the screws on the upper shroud and prop it open with a 6" long block of wood (which gives you access to the evaporator but you cannot remove it from the housing without breaking the refrigerant lines so..

What I did was take my garden sprayer and put in some Purple Zep and soaked the evap down with ZEP. Every year mine gets loaded with fine chaff. I soak it down and let it 'cook' for about 15 minutes and refill the sprayer with clear warm water and flush out the evap with that. The crud and dirt will drain out the condensate tubes that go under the tractor. Keep rinsing until the water is clear, button it back up and reinstall the roof. The roof is very lightweight, just bulky. While you are up there, take an air gun and blow off everything, the dust will be everywhere up there. You might want to remove all the connectors and put di-electric grease in them, I did the first time.

I also flipped the roof over in the shop and applied Reflectix foil-bubble-foil insulation to the underside of the roof. There is no insulation and it gets hot in the sun and your ac has to overcome that heat. The Reflectix really cuts the heat load on your ac. You can buy it by the roll at Lowes and it's cheap. I cut mine to size with scissors and glued it to the underside of the roof with 3M contact spray cement.

Like I said previously, my ac is super cold. I think reducing the under roof heat had a lot to do with it too. Just be acreful with the roof. I priced a new one from Kubota. Granted mine is larger but a new one is 13000 bucks.

 

[Snappy BX]

Condenser gives off heat, high pressure, must be clean, out in environment. evaporator low pressure cool, cool near occupants, hot, high pressure always away from occupants.

 

[5030]

We should be using the correct terminology to avoid confusion. The condenser coil is in front of the engine fan, the evaporator coil is stacked with the heater coil in the cab roof.

Actually Rick, on a Kubota roof mount, the heater core is downstream from the evap. The evap is separate with the heater core about 8" farther down in the lower shroud. Interestingly on mine, the air flow direction flaps are electronically controlled. No mechanical linkage at all. Even the heater (hot coolant) valve is electronic. I considered putting WOG valves on the heater lines until I saw how the heater control valve worked. It's a very positive stop so no hot coolant bleed at all when in ac mode. Nice design, It's a Denso unit but there is a lot going on up there.

 

[5030]

One thing I did years ago was I added a 12 volt automotive cooling fan to the front side of the condenser under the hood. With my Kubota at least, there are a lot of heat exchangers between the between the condenser and the fan so airflow can be an issue at lower rpm. I have the condenser, then the oil cooler, then the air to air unit and finally the radiator.

I wired the fan (pusher) to the ac compressor electric clutch hot wire with a relay so when the ac clutch is engaged, the fan runs. Clutch energized, fan on. Clutch deenergized, fan off.

Every little bit helps...

 

[TimP]

If yours is like mine (and I presume it it), inside the cab, if you look up, there will be a number of Phillips head screws around the edge of the inner headliner. Every other one needs to be removed to remove the roof Problem is, which every other one.....

Simple. Remove one. If it's long it's a roof screw. If it's short, it's a headliner screw. All the long ones have to be removed to get the roof off. In my case, it's 10 screws. Yours may be different.

Cleaning the evaporator is a real pizzer. Lots of stuff up there (depending on what options you have), I have all of them. if your unit is like mine, you won't be able to completely remove the upper shroud without removing the heater core and on mine at least, the heater core is hard piped so what I did was take out all the screws on the upper shroud and prop it open with a 6" long block of wood (which gives you access to the evaporator but you cannot remove it from the housing without breaking the refrigerant lines so..

What I did was take my garden sprayer and put in some Purple Zep and soaked the evap down with ZEP. Every year mine gets loaded with fine chaff. I soak it down and let it 'cook' for about 15 minutes and refill the sprayer with clear warm water and flush out the evap with that. The crud and dirt will drain out the condensate tubes that go under the tractor. Keep rinsing until the water is clear, button it back up and reinstall the roof. The roof is very lightweight, just bulky. While you are up there, take an air gun and blow off everything, the dust will be everywhere up there. You might want to remove all the connectors and put di-electric grease in them, I did the first time.

I also flipped the roof over in the shop and applied Reflectix foil-bubble-foil insulation to the underside of the roof. There is no insulation and it gets hot in the sun and your ac has to overcome that heat. The Reflectix really cuts the heat load on your ac. You can buy it by the roll at Lowes and it's cheap. I cut mine to size with scissors and glued it to the underside of the roof with 3M contact spray cement.

Like I said previously, my ac is super cold. I think reducing the under roof heat had a lot to do with it too. Just be acreful with the roof. I priced a new one from Kubota. Granted mine is larger but a new one is 13000 bucks.

Thanks for all of that info 5030 ! I'll try adding the tape too.

 

[5030]

Thanks for all of that info 5030 ! I'll try adding the tape too.

Like I said, been there and did all that. I didn't do it all at one time, did the roof first and then the next year did the fan and then a recharge and I did replace the perimeter gasket on the roof as well. Mine got hard and was cracked so I replaced that just last year (remember mine is a 2004). That was 100 bucks at the dealer but it comes with adhesive on it so it's easy to apply. Did the side mount filter gasket too. Used weather stripping (self stick) on that.

It's only money after all.

 

[TimP]

It's only money after all.

What the heck..... can't take it with you.....

 

[RickB]

Actually Rick, on a Kubota roof mount, the heater core is downstream from the evap. The evap is separate with the heater core about 8" farther down in the lower shroud. Interestingly on mine, the air flow direction flaps are electronically controlled. No mechanical linkage at all. Even the heater (hot coolant) valve is electronic. I considered putting WOG valves on the heater lines until I saw how the heater control valve worked. It's a very positive stop so no hot coolant bleed at all when in ac mode. Nice design, It's a Denso unit but there is a lot going on up there.

Point being the condenser is not in any part of the cab. The heater core and evaporator are enclosed in the same housing on a B3000.

 

[Tx Jim]

We should be using the correct terminology to avoid confusion. The condenser coil is in front of the engine fan, the evaporator coil is stacked with the heater coil in the cab roof.

If one wants to keep this AC discussion correct then R134A should be referred to as a ""refrigerant not Freon"".

IMHO I agree AC components operate more efficiently the cleaner the exterior is of theses components BUT I've owned cab tractors for many yrs operated in very dusty conditions & rarely have I had to clean evaporator to get these AC systems to cool in Texas heat. One tractor AC cooling exception that I owned was a Kubota M4900 that the AC cooling capacity was at bare minimum IE barely kept operator comfortably cool if engine rpm's were kept higher. I would check condenser/radiator for chaff then attach gauges to determine the low & high pressures of the charge of refrigerant before inspecting evaporater.

 

[5030]

Point being the condenser is not in any part of the cab. The heater core and evaporator are enclosed in the same housing on a B3000.

So are mine actually, same thermoplastic housing but in my case there is a physical separation between the evap and the heater core of about 8". That may or may not apply to all models of Kuobota cab tractors.

I just refer to 134A as Freon which is isn't, I know that 134 is the non ozone depleting replacement for Freon.

One important note here is, Kubota cab models that have the ac and heater outlets in the roof, have the 'works' in the roof as well. Models with the ac and heater outlets in the dash, have the 'works' under the seat pan and they are even harder to access to clean.

Some tractors will accumulate chaff and dust in the ac units easier than others will, all depends on how well the units are isolated from 'dirty' incoming air. In my case, my unit seems to get dirty pretty quick. One sure way to tell if the evap has a load of dirt it is smell the processed air coming from the vents. If it has an odor to it, chances are the evap is clogged.

My buddy down the road has a large seed operation and a fleet of late model large JD tractors and he has to clean the evaporators yearly. Some need cleaned, some don't.

One thing I do to reduce the dirt getting past the cab filter and through any openings in the perimeter seal around the top of the ROPS structure is I operate the ac (and heat) in the winter, in RECIRCULATE mode. In recirc mode, mine don't draw in outside air, the outside air (for the most part but not 100% is blocked from entering the roof space where the unit (mine) is located.

Besides, in recirc mode, the ac unit is recoooling the already cooled air in the cab so the heat exchange load is less and the ac can more easily keep the cabin air cold..

That can be an issue in high humidity but 99% of the time, recirc mode works just fine.

A certain amount of outside are will get in even in recirc mode but the percentage is greatly reduced.

First and foremost is keeping the underhood heat exchangers as well as the radiator clean and free of dirt and chaff. I clean mine every day when I come in from the field and every couple days I backwash the radiator with water using one of those 'Genie' wands. Airflow is paramount through the HX's in the engine bay. Clean HX's are happy HX's. A clogged rad or air to air unit or condenser or oil cooler cannot exchange the heat produced by the components that produce it.

Like I stated previously, some Kubota models have the 'works' under the roof, some have the 'works under the seat. Easiest way to determine that is where the outlets are located. If the outlets are in the dash, the works are under the seat. If in the roof headliner, they are in the roof cavity.

Even though it's a chore to access the works in the roof, it's still much easier than under the seat.