I am working on an doosan 140 lc-v excavator at work trying to get some cold air out of it. The compressor has been replaced it is a nippondenso model 10 pa and uses 134a. The system uses a txv as well as the condenser mounted behind the cab with an electric fan to cool it....heater valves are shut.
Flushed system first, added 7 oz of page 46 oil for new compressor...then vacuumed it down and it held for 25 mins...it got a new drier, cleaned condenser. Charged to 31 oz. ( Per doosan dealer) and it was blowing 65 out of the vent low side pressure was 10psi on the low side and 200 high side on a 75 degree day.
Did some research and seemed the expansion valve could have been sticking or stuck ( the spring didn't have tension on it like the new one ) , so I replaced it and vacuumed it down and charged again...now it will freeze u out in the morning 39-40f out the vent 10 psi low side and 170 ish high side in the morning 70 degrees outside...
As the day goes on the vent temp warms to 55-60 and it doesn't keep the cab cool...low side pressure is once again 10-15 psi and high side will be around 200 for an 80 degree day....
The high side seems good but why is the low side only at 10 psi ?? When the compressor comes on it stays on for about 18 seconds and then it cuts off for 40-45 seconds...I am wondering if I got a bad expansion valve and it is starving the low side ??
Excavator a/c
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H8theheat
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Re: Excavator a/c
2 The bearing on the pulley seized up and was easier to replace the compressor.
4 expansion valve is brand new but I know it's possible it could be defective.
5 air flow is great at all times and evaporator fins were cleaned
Both high and low side ports are on the back of the compressor.
I pulled a belly pan yesterday and I could see where the lines run into the floorboard before they enter the expansion valve/evaporator....big line was 57-62 degrees and small one was like 72-75 degrees with system running don't know if this helps but it's more info.
I know I have a problem somewhere but what should the low side read theoretically for a properly cooling system ? Everywhere I have read about low side pressures it has to do with orfice tube systems and not txv should they run roughly the same pressures ?
4 expansion valve is brand new but I know it's possible it could be defective.
5 air flow is great at all times and evaporator fins were cleaned
Both high and low side ports are on the back of the compressor.
I pulled a belly pan yesterday and I could see where the lines run into the floorboard before they enter the expansion valve/evaporator....big line was 57-62 degrees and small one was like 72-75 degrees with system running don't know if this helps but it's more info.
I know I have a problem somewhere but what should the low side read theoretically for a properly cooling system ? Everywhere I have read about low side pressures it has to do with orfice tube systems and not txv should they run roughly the same pressures ?
Re: Excavator a/c
A 10 psi suction with a suction line temperature around 60f would indicate a starved evaporator.
Either a bad TXV, plugged capillaries in the evaporator, a plugged receiver or a damaged liquid line.
Since you indicate a clean system, with no compressor failures the evaporator is likely clear.
Is the new receiver / dryer installed with flow in the right direction?
Have you checked the liquid line for damage? Excavators get used hard. A rock can flatten a line with ease.
Where any restriction is, there will be a cold spot in the liquid line. Check the dryer and liquid line for cold spots by feel.
Either a bad TXV, plugged capillaries in the evaporator, a plugged receiver or a damaged liquid line.
Since you indicate a clean system, with no compressor failures the evaporator is likely clear.
Is the new receiver / dryer installed with flow in the right direction?
Have you checked the liquid line for damage? Excavators get used hard. A rock can flatten a line with ease.
Where any restriction is, there will be a cold spot in the liquid line. Check the dryer and liquid line for cold spots by feel.
Re: Excavator a/c
There was a small kink in the liquid line it made a small difference when I straightened it...
I had to take the evaporator back out for this and while it was out I took every line loose and blowed through them , they all flow freely...even blowed through the drier it flows free too....blowed through the evaporator ( took expansion valve off ) also blowed fins clean but they weren't dirty really and blowed through the condenser and nothing is blocked....drier is installed with flow arrow in the right direction. Vacuumed the system back down and recharged...
now at 85 degrees ambient at idle, low side reads 25 and high side reads 200 roughly 46 degrees at vent...at full throttle which is what it runs at most of the day low side is 12 and high side is 200 vent temp is around 55 degrees
Isn't there a way to measure the temp before and after the expansion valve and or the condenser and it should be cooling x amount of degrees or else the valve needs adjusting or is bad ??
I had to take the evaporator back out for this and while it was out I took every line loose and blowed through them , they all flow freely...even blowed through the drier it flows free too....blowed through the evaporator ( took expansion valve off ) also blowed fins clean but they weren't dirty really and blowed through the condenser and nothing is blocked....drier is installed with flow arrow in the right direction. Vacuumed the system back down and recharged...
now at 85 degrees ambient at idle, low side reads 25 and high side reads 200 roughly 46 degrees at vent...at full throttle which is what it runs at most of the day low side is 12 and high side is 200 vent temp is around 55 degrees
Isn't there a way to measure the temp before and after the expansion valve and or the condenser and it should be cooling x amount of degrees or else the valve needs adjusting or is bad ??
Re: Excavator a/c
Sure looks like the TXV is starving the evaporator.
You said you replaced the TXV. I have run in to issues where the Heavy Equipment cross reference was not terribly accurate before.
What type of TXV does this excavator have? Block type or in line with capillary tube?
It could be a bad valve, the wrong valve, or an adjustment - not all valves are easily adjusted.
You said you replaced the TXV. I have run in to issues where the Heavy Equipment cross reference was not terribly accurate before.
What type of TXV does this excavator have? Block type or in line with capillary tube?
It could be a bad valve, the wrong valve, or an adjustment - not all valves are easily adjusted.
Re: Excavator a/c
It is a block style no capillary tube, but there is a allen head cap at the bottom would this be the adjustment ??
I did keep the old valve and I just took the Allen head cap loose and there is and o ring then the tension spring...I guessing it it non adjustable because if I loosen the hex cap I'm sure the o ring will leak refrigerant ?
I did keep the old valve and I just took the Allen head cap loose and there is and o ring then the tension spring...I guessing it it non adjustable because if I loosen the hex cap I'm sure the o ring will leak refrigerant ?
Last edited by H8theheat on Thu Apr 09, 2020 4:48 am, edited 1 time in total.
Re: Excavator a/c
That's the exact valve !!!
Last edited by H8theheat on Thu Apr 09, 2020 5:34 am, edited 1 time in total.
Re: Excavator a/c
Since the manufacturers make hundreds of different valves from that same piece of aluminum extrusion, it can be very easy mix them up.
For instance the Denso 4752004 looks like that. Used in Acura, Cadillac and Honda, common in the UA. While Toyota used the Denso 4750107 valve in nearly everything from the little MR2 to the Land Cruiser. Yet the Denso 4750511 only fits 2 years of Scion Xa /Xb.
Is there a part number stamped on the original valve anywhere?
Sounds like the CV on the valve is too small. It can regulate properly only at low compressor rpm.
For instance the Denso 4752004 looks like that. Used in Acura, Cadillac and Honda, common in the UA. While Toyota used the Denso 4750107 valve in nearly everything from the little MR2 to the Land Cruiser. Yet the Denso 4750511 only fits 2 years of Scion Xa /Xb.
Is there a part number stamped on the original valve anywhere?
Sounds like the CV on the valve is too small. It can regulate properly only at low compressor rpm.
Re: Excavator a/c
This valve has a part number E41620-0222 from doosan. It's $40 I'm tempted to just replace it...there is ALOT of crap behind the seat you have to take apart to get to it, it is about a 5-6 hour job start to finish.
Re: Excavator a/c
Sorry to hear about the labor on that one. Heavy equipment is never easy.
Interesting. That part number takes me back to a 2003 - 2006 Kia Sorrento.
Which would make sense, given the common country of origin, and probably a similar cabin volume.
Interesting. That part number takes me back to a 2003 - 2006 Kia Sorrento.
Which would make sense, given the common country of origin, and probably a similar cabin volume.