08 dodge ram 2500 pressure quesitons

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clsmith29
Posts: 1
Joined: Tue Jul 03, 2018 7:32 am

08 dodge ram 2500 pressure quesitons

Postby clsmith29 » Tue Jul 03, 2018 7:33 am

DIYer here. I have manifold gauges, vacuum pump, recovery pump and cylinder. I just replaced the evaporator, accumulator/drier, orifice tube on my truck, which is a 08 Dodge Ram 2500. I had an evap leak and heater core issue. While I had the plenum out I rebuilt the entire thing in hopes of not having to remove the dash again in the near future. The truck says it holds 1lb 11oz of refrigerant, I have refilled it with what should be the proper amount but I can not get my pressures and temps right. According to a r134a pressure chart @ 85deg I should have pressures in the range of 45-55 on the low side and 225-250 on the high side. I am more like around 35 on the low side and 175 on the high side. When I check my superheat and subcool temps I have the following. Subcool: gauge on high side reads 175 psi which equates to around 120 deg on the PT chart/gauge. My line temperature at the high pressure inlet is only around 93 deg. I have seen it up around 100 but not more than that. Superheat: low side pressure is reading around 35psi which equates to around 30 deg on the chart/guage. My lines at my evaporator are running around 47deg, which puts m y subheat at 17. I did manage at some point to get my evap temps down to like 42 and the truck was cooling great sitting at idle, but when I drove around the block by the time I got back to the house I had 65 degree air coming out of the vents. I figured at that point, I may have overcharged it so I evacuated a little with my pump but no dice. The best I’ve been able to achieve are the numbers above with 50 degree air blowing out of the vents while idling in the yard and driving around the block. What do I need to check next? It seems to me my out put side of my compressor may not be doing what its supposed to be. From what I can tell my condenser is only dropping temps of lines, at the most 10 degrees from input to output. My condenser fan runs as it should. One thing I noted is my compressor never seems to shut off. Once the system has enough refrigerant in it to activate the clutch it runs as long as I have the ac on, no cycling at all. Is that correct? Thanks for any help you guys can offer, Clay.

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