Kubota B3030 Air Conditioner

[RiverHead001]

For a Kubota B3030 with enclosed cab:
The air conditioner was serviced at the end of the season last year. This year the air conditioner works (blows cold air) for approximately 20 minutes upon startup but after that blows warm air (tried opening cab doors to trigger the Tstat but still warm air.)

Not sure if the issue may be a Tstat or the compressor. Any thoughts or experience with this would be appreciated.

Thank you in advance.

 

[Russell King]

Try seeing if the heater hoses are both warm, going to and coming from the heater core. The control valve may be leaking and the heater is really on.

Or just remove the hoses and connect them together to see if it stays cool.

 

[RiverHead001]

Try seeing if the heater hoses are both warm, going to and coming from the heater core. The control valve may be leaking and the heater is really on.

Or just remove the hoses and connect them together to see if it stays cool.

I am very grateful for your response Russell King. I will attempt your suggestion tomorrow.

Would the disconnect points for the heater hose be as highlighted on the attached diagram?

Thank you again for your suggestions.

 

[Mountainman]

No expert here on this subject but recently aquired a b3030 cab and been looking through wsm. Have you tested the pressure yet? There is a high and low pressure shutoff switch. Also have been told by others that a lot of cooling issues are caused by the unit in the roof not being cleaned. Haven't taken my roof off to clean yet but will be soon. Again no expert in this area

 

[Russell King]

I am very grateful for your response Russell King. I will attempt your suggestion tomorrow.

Would the disconnect points for the heater hose be as highlighted on the attached diagram?

Thank you again for your suggestions.

Yes that is them. Since they are a long run you should be able to find a point to see if they are both warm.

You can just remove those two hoses at the highlighted ends and connect them together to stop from dripping everywhere. Then a new hose connecting those two highlighted engine points.

Don’t run it without those two points connected together or you will drain the radiator out and make a mess, and overheat.

 

[Old Machinist]

K.I.S.S.

First clean the radiator and condenser screens and back wash the radiator and condenser with a hose.

Next put a set of air conditioner gauges on it and report the readings.

 

[Spam Bot]

To stop the circulation to the heater core, create an H fitting and install a shut-off valve on each hose above the H, as well as a shut-off valve in the middle of the H. In cold weather, the two valves will be open, allowing the coolant to flow from the engine to the heater core and back. The center valve will be closed to prevent recirculation. Reverse the valves as described for use in warm weather. If you were to disconnect the two hoses from the heater core and then reconnect them, you might have trouble getting the air out of the heating system when cold weather arrives. I learned this from the heater in my BX that had an air bubble stuck in the heater core, causing poor heating when I needed it most. I had to remove the heater and place it on the ground to burp the air out of it. I know that this is also a problem in some automobiles, and the dealerships have an expensive special tool for eliminating the issue.

 

[chim]

IF it turns out to be unwanted flow through the heater core, check the routing of the existing heater lines. The parts diagram doesn't show a three-way valve for the heater. That leads me to believe you should be able to install one simple valve.

When I built a cab for my L3200 I added a heater that was plumbed into the bypass. With that application flow had to be maintained so the bypass continued to work so I had to do the "H" piping previously mentioned. If you want to experiment, HF has a set of line clamp set for $15.

 

[BAP]

I am very grateful for your response Russell King. I will attempt your suggestion tomorrow.

Would the disconnect points for the heater hose be as highlighted on the attached diagram?

Thank you again for your suggestions.

All you need to do is to put a shut off valve in 1 of the heater lines. Go to the local hardware store, buy a ball valve, 2 nipples that thread into it with hose barbs on the other end of them, 2 pipe clamps. Cut one of the lines with a utility knife and put the valve in. I used to do that with many of the tractors we had on the farm, particularly the Case-IH ones because the cheap plastic heater shut off valve in the cab would leak by causing the AC to shut down. Summer time we shut off the ball valve and everything worked great. Cheap easy fix. Stupid to have to, but sometimes you gotta do what you need to do to make stuff work.