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My A/C system is gonna kill me.


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Krisackermann
New User

Aug 5, 2019, 7:40 PM

Post #1 of 5 (1699 views)
My A/C system is gonna kill me. Sign In

Little off topic here but looking for some help or pointers. I have a 2016 Peterbilt 365 A/C system I am working on. With the truck at idle my low side is at 30 psi and high side is at 150 psi. When you bring the RPMs up to 1500 my low side will just to 18psi and shut the system off until pressure build back up. The truck takes 2.8lbs. Does not have a thermostatic switch in the evap. It runs it temps On the evap in junction to pressure. I have replaced the compressor multiple times. The evap and condenser have been replaced. All the A/c hoses have been replaced. The expansion valve and the drier has been replaced multiple times. The low and high pressure switches have been replaced as well. Also the HVAC box has been replaced. If I jump the low pressure switch it will stay on with the low side running at 15psi but will freeze up the evap over time. I have tried to bump up the amount of refrigerant some and it doesn’t make a difference. Was told to check if there was to much oil in the system as it takes 300cc for the complete system. I have flushed all the lines the condenser and the evap. I drained the compressor best I could and made sure system has the proper amount. My issue just won’t go away. Has anyone ran into this at all or knows what I could go to next.


Krisackermann
New User

Aug 5, 2019, 7:43 PM

Post #2 of 5 (1695 views)
Re: My A/C system is gonna kill me. Sign In

Also have been talking with the manufacturer and they have told me they don’t know sorry and told me to kick rocks.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 5, 2019, 9:27 PM

Post #3 of 5 (1681 views)
Re: My A/C system is gonna kill me. Sign In

What happened that this needed a new HVAC box at all? It's new for a "semi" truck totally not my thing but principles apply to any of this. Why would there be any chance of too much oil?


Who's screwing around with this YOU or a tech with a clue about A/C at all? It's critical and too important IMO for an over the road rig could travel anywhere.


Enough I just happened to work on-line with a very clever and well informed "big rig" driver and tech with A/C all about it for his own user name > Cornbinder89 < at another site if you wish made harder to sign up ignore that just don't forget what you said at sign up - free like here no interest in anything but help for you or a fix.
Pressure you posted are not in line with anything that works in a temp that requires A/C.
I suggest you have some temperature measuring thermos at the ready and reading for that handy along with ability to record pressures under what conditions include RPM, airflow over condenser set up and any history as to why this needed anything yet if even some accident just what was damaged and how fixed.
Refer back to this thread and do mention the oil issue again. This may also use a sight glass could see that otherwise you don't know unless starting all freshly flushed out and start from scratch.


I'll quit it this guy lives this stuff with these rigs based out of Iowa central to all of US goes anywhere the roads go.
Visit here there's no vested interest in you and not there to sell anything to anyone...………
Link deleted (just post up top if you come like here we'd catch it wherever you ask whatever)
That should just click you can check it out first sign up keeps spammers out is the only reason. Wish you luck and see you there or here just hate to see you miss out on a working trucker who fixes all his own A/C would know this stuff really well,


Tom



(This post was edited by Hammer Time on Aug 6, 2019, 7:41 AM)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 6, 2019, 7:47 AM

Post #4 of 5 (1651 views)
Re: My A/C system is gonna kill me. Sign In

This AC system doesn't work any differently than any other automotive AC system. There does seem to be some confusion as to what type of system it is.

You state it has an expansion valve but no thermostatic sensor in the evap. That doesn't jive. It definitely should have a thermostat on an expansion valve system. A cycling system with an orifice tube would be regulated by pressure and the expansion valve system should be regulated by a thermostat.

You also didn't mention what the high side did at 1500 RPMs. That would give us hints as to what is happening.
Also, where is the low side port located in the system?



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Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 6, 2019, 9:43 AM

Post #5 of 5 (1646 views)
Re: My A/C system is gonna kill me. Sign In

OK, keep this here and yes need high side at 1,500. Know it still should be cooling at idle reading about 2.5 X the temp in F. If not it isn't "condensed" if you will so not much or enough to "evaporate" to do much of anything.
At a glance would say low on charge but not so fast! X valve could be all wrong or any type of heat sensor used. New HVAC box! Why? That's a key question it's too new never mind miles expect these to wail up high miles in no time IDK average cars/trucks anyway miles don't seem to wreck A/C by miles vs more time, some lack of use?


Tom







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