M9540 ac

[psbhouston]

Ok - I can use some help! AC evaporator was plugged due to all of the leaks in the intake ductwork. Cleaned it and sealed everything with high-tech AC tape. Now it blows like new. Decided to hook up gauges since there is airflow.

We are now getting 60 psi on low and 290 on high. 92 degree ambient / 55% humidity.
Are there specific pressures to hit with the Kubota or do you use a standard chart? It seems high on high side. Do i evacuate the system - recharge with weighed amounts? I would bet that my guys added to the system with one of those cheap cans and one gauge etc.
Can you guys help!!!
Many thanks.
Greg

 

[psbhouston]

UPDATED VALIES

We operated the system @ 1800 rpm engine speed. Ac compressor stays engaged. Low side is 45~50 psi and high side settled at 330 psi. Air vent temp is hovering around 63 degrees.

 

[Bulldog]

Glad you got it going. Cab tractors suck without air.

 

[psbhouston]

it is not fixed yet!

I am sure that one of my guys added freon in the field and overcharged and introduced air into system. I evacuated the system with a vacuum pump and checked for leaks. None noticed. The systems holds 1.87 to 2 lbs of R134. I charged it with about 20oz and pressures are already back to 50psi Low / 280psi High. Air temp at vent is 70 degrees so its cooling a bit - but what am I missing?

Manual says clean condenser / check "heat sensitizing tube and expansion valve??? What is a heat sensitizing tube?

I thought expansion valve would not cause high pressures on both sides? But - I know only enough to be dangerous. Need help please - don't want to kill the system.

just to add further - I pulled the condenser out on the slide in order to clean it and make sure no dirt was there. When I pulled it out the pressures on both low/high went nuts. High pressure cut out kicked in. I slid it back in place and it is operating at 45/275.

should I just shoot it or the mechanic?

many thanks
Greg

 

[kc8fbl]

Is there any AC filters in the cab? Those could possibly be hindering your cooler air flow.

 

[Tx Jim]

it is not fixed yet!
just to add further - I pulled the condenser out on the slide in order to clean it and make sure no dirt was there. When I pulled it out the pressures on both low/high went nuts. High pressure cut out kicked in. I slid it back in place and it is operating at 45/275.Greg

Pressure variation with no fan sucking air through condenser with it pulled to the side is normal.

I know the AC on my M7040 operates(cools) much better than on the M4900 I owned before the M7040. On the M4900 cutting hay the condenser/radiator had to be blown out every day but not so on the M7040