D5k air conditioner question

[dirtmonkey]

:beatsme Hey guys, got a question. My d5k a/c is not cooling like i think it should. Yes i know its alot of glass and not a refrigerator but , its 100* and i tinted windows and hung curtans to stay cool ! The amb. temp. is 100*, the high side is 250-270, the low side is 13-15 and the discharge air temp is 80*. I keep new or clean filters. Am i asking too much or is this the norm . This is my first dozer with a cab. :Banghead Gotta love it, one more thing to work on!

 

[Lee-online]

As a general rule the AC temp should be 30 deg lower than the ambient when measured directly in the vent.

Make sure the condenser isn't plugged and the fans are blowing air. These are located above the cab at the rear.

 

[dirtmonkey]

Fans are working properly. Condenser is not plugged up, its cleaned every afternoon. I even put a smaller screen on top to keep out pesky twigs when tree pushing. I figure i may be asking too much of the system. Ive been told 134a is sensitive to charge. Can i boost the charge a little ? And thanks for responding! I was hoping you would see this post. Love the CAV patch, go ARMY !

 

[stinkycat]

Dirtmonkey check the evaparater and make sure it's not icing up that will kill your cooling. Make sure you keep the filters clean and check that the coils aren't pluged

 

[Iron@Dirt]

With a temp gun at air outlet you can add or subtract a little to see if which one could help.

 

[PAcattech]

Try shutting off valves on engine for your heater lines

 

[swampman]

13-15 on the low side is a tad low.

 

[firetruck dvr.]

We got a new D5K last thursday and I thought the same thing about it. It got to about 96 that day and it would just barely keep up. I did not say anything about it because im use to a hoe. I just thought the cab was so much bigger that it was doing all it could do? I will have cat check it out when they come get it to install the winch!!

 

[dirtmonkey]

:Banghead Well an up date. the high side pressure is closer to where it should be but, the low side is still at 13-15. There is no valves for heater lines just the electronic control. Along with the dealer we have come to a conclusion that it may be an clogged line filter or orifice tube. Some say we hit 105* today and got 70* air at the vent , so i guess i cant complain too much ? I am still thinking about swapping out the line filter though. just to pass on info the dealer said it takes exactly 2.9 lbs of refrigerant. I hope i quoted him correctly.Any other thoughts would be great and thanks to those who responded!:notworthy Maybe my troubles can help some one else

 

[willie59]

Have you made sure the evaporator inside cab isn't clogged with dirt externally? Is the compressor running continuously, or is it cycling in and out?

If you change out that filter/dryer, you do have a vacuum pump to do an evacuation, no?

 

[Lee-online]

The heater valves should be on the engine where the heater hoses attach. Keeping them close helps keep it that much cooler by not letting the hot coolant up to the heater core and then into the cab.

The orifice is in the dryer. The dryer should be replaced, i believe every 2000 hrs.

 

[Lee-online]

Have you made sure the evaporator inside cab isn't clogged with dirt externally? Is the compressor running continuously, or is it cycling in and out?

If you change out that filter/dryer, you do have a vacuum pump to do an evacuation, no?

With a Cat dryer it comes with a vacuum in it and has quick couplers so no need to evac the system.

 

[willie59]

With a Cat dryer it comes with a vacuum in it and has quick couplers so no need to evac the system.

Sweet!

 

[dirtmonkey]

I dont want to open up the evap. box just yet, not until i get it off the job. I really dont think its dirty, Im real picky about keeping filters clean or new ones in it, but that dont always mean anything. Ive noticed the comp. is quiet, not like the one in my truck, so i asked the service guy and he said thats normal. You know how you can here it cut in and out, this does not. As to the valves , there are no shut off valves. They may appear later if you know what i mean Im going to suffer through until i can git back to my shop but if i can replace the filter ( if its a quick connect ) in the field in a timely manner im willing to spend the money. Thanks for the suggestions! Keep em coming! Maybe its a factory flub

 

[dirtmonkey]

Well looks like lee answered part of the question while i was typing ,you know one finger at a time

 

[firetruck dvr.]

:notworthyHad Cat service tech out wed to check out my A/C problem. It was 95 degrees outside and it was only putting out 64 degree air. Turns out it was overcharged from the factory. (380 high side) so he bled some off to around 280 and it started blowing 52 degree air. Yesterday it would fog the windows on low!

 

[dirtmonkey]

You lucky devil, and your getting the same weather as us okies! :Banghead Well maybe you can at least write my name in the fog next time , im jealous.:notworthy By the way , what did they charge for the service call, if you dont mind my asking ?

 

[firetruck dvr.]

Nothing machine only had 8 hrs on it!

 

[woodstock1]

:Banghead Well an up date. the high side pressure is closer to where it should be but, the low side is still at 13-15. There is no valves for heater lines just the electronic control. Along with the dealer we have come to a conclusion that it may be an clogged line filter or orifice tube. Some say we hit 105* today and got 70* air at the vent , so i guess i cant complain too much ? I am still thinking about swapping out the line filter though. just to pass on info the dealer said it takes exactly 2.9 lbs of refrigerant. I hope i quoted him correctly.Any other thoughts would be great and thanks to those who responded!:notworthy Maybe my troubles can help some one else

You need to change your liquid line drier....with the pressures you mention, you have a restriction on the high side at your metering device...(orifice, cap. tube, or expansion valve, whichever you have)...

Rule of thumb is you should be running anywhere from 30-35 lbs on the suction line (low side) that would be a saturated vapor temperature of 34*-39*...and with at least a 15* delta T, you should be blowing out 49*-54* air.....

The suction pressure you mentioned, 13-15 psi equals a saturated vapor temperature of 11*-14*, which would be common if it were a freezer....but it is starving the evaporator....

And just FYI.....R134A has a critical point (no cooling properties left) at about 275-280 psi....so air flow across the condenser is critical on those 100* days.....always keep it clean!!...head pressure always runs higher on equipment/cars because of the engine/radiator heat and the variable speed of the compressor.

 

[dirtmonkey]

going to replace accumulator but forgot to ask about adding any oil and what kind. it is sat afternoon and going to start work on it sunday at noon. Any help would be great and thanks to all who have helped this far! think i will start new thread to catch some ones eye. thanks!