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Topic: Need Dash A/C gas pressures for 2005 U270 (Read 639 times) previous topic - next topic

Need Dash A/C gas pressures for 2005 U270

I have my coach in for oil/filter change and routine service. My dash a/c is just not cooling properly. The tech asked me what the correct gas pressures should be on the dash a/c system when everything is working properly. Tomorrow he is going to charge the system  to proper levels then start troubleshooting. I am in Vermont in 70 degree daytime weather but  will be heading south into warmer climates in September. What pressures should I give to the tech?
Thank you in advance
2000 U270 34' WTFE Build 5756 "Ole Red"
2014 Honda CRV
Washington, Vermont
Lady Lake, Fl,  Independence, VA
Former owner of 2002 U320, 2003 U320, 2005 U270

Re: Need Dash A/C gas pressures for 2005 U270

Reply #1 –
Same as any automotive-type system with your same refrigerant.  Nothing special about a motorhome dash A/C.

Assume it is R134A.  Plenty of charts on-line.  Look up for your ambient temperature.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Need Dash A/C gas pressures for 2005 U270

Reply #2 –
Think if the "tech" had to ask you I would find one a little more knowlegdeable,what is he not asking you.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Need Dash A/C gas pressures for 2005 U270

Reply #3 –
Quote from: John44 –
Think if the "tech" had to ask you I would find one a little more knowlegdeable,what is he not asking you.

^^^^^^Agree^^^^^^
Chris and Tammy White  CDA Idaho
Previous owners 1997 U295 36' 3126 Cat 300 HP Build # 4998
Former Foretravel tech & RVIA certified tech
Former owner Custom Satellite home/RV satellites 
Former owner Vans LTD  van conversions
Unemployed, panhandler, drag racer NHRA #6348

Re: Need Dash A/C gas pressures for 2005 U270

Reply #4 –
There's too many different system designs out there to have exact operating pressures and temperatures. The "rule of thumb" I use for years on the high side pressure is ambient temp x2 plus 30 will get you close in what the reading should be and if I got anywhere of 30 to 50 degrees lower out of the dash vent than outside ambient temp I call it good.  FYI, your high side should never be over 250lbs but here in 118 degrees summers it's hard to maintain that rule with some equipment.
The biggest thing I see today with older cars and RV's is that their system have  contaminants such as air or junk, wrong size of compressor, no oil or to much oil, low refrigerant or to much and plug up evap coils or fan blade.
Bottom line if the tech is asking you for operating  parameters I would to be concern.
Steve
2001 U320 40' IF$ Build #5798
2018 Jeep Grand Cherokee Trailhawk Toad
2015 GMC Duramax HD2500 Toad
2014 Polaris RZR 1000
Litchfield Park, AZ- Soon to be Paulden, AZ

Re: Need Dash A/C gas pressures for 2005 U270

Reply #5 –
Quote from: Willy White –
There's too many different system designs out there to have exact operating pressures and temperatures. The "rule of thumb" I use for years on the high side pressure is ambient temp x2 plus 30 will get you close in what the reading should be and if I got anywhere of 30 to 50 degrees lower out of the dash vent than outside ambient temp I call it good.  FYI, your high side should never be over 250lbs but here in 118 degrees summers it's hard to maintain that rule with some equipment.
The biggest thing I see today with older cars and RV's is that their system have  contaminants such as air or junk, wrong size of compressor, no oil or to much oil, low refrigerant or to much and plug up evap coils or fan blade.
Bottom line if the tech is asking you for operating  parameters I would to be concern.
Steve

Steve Knows his stuff... Fixed my AC and its still kickin cold air!!

Been busy with the Grand baby but next time we are down Ill call you for lunch

Re: Need Dash A/C gas pressures for 2005 U270

Reply #6 –
I misunderstood the question from the tech. He was asking how many pounds of refrigerant  total did the system need if starting at zero. Brad at Foretravel said 6 pounds. My mistake.


2000 U270 34' WTFE Build 5756 "Ole Red"
2014 Honda CRV
Washington, Vermont
Lady Lake, Fl,  Independence, VA
Former owner of 2002 U320, 2003 U320, 2005 U270