Community Forums

Azborn76 · 05-18-2020, 03:25 PM

Hello
I'm wanting to give my dash AC a tune up before a long road trip this summer through the deep south. I have a 2003 Dolphin 6355 on a 2002 W22 chassis. I have been trying to educate myself about how to use a set of manifold gauges to properly check the 134 levels. However I cant seem to find the low and high pressure ports. Looking at it I can find two ports on what I would best describe as a L fitting which I believe is the accumulator which is right along side my Evans unit they both are of different sizes high and low but I'm confused if this is where I should hook the manifold gauges up to. My dumb brain doesn't think there far enough apart being housed on the same valve to be the high and low side. The Evans model is RV200668. Any help would be greatly appreciated.

Belgian · 05-18-2020, 09:17 PM

Gauges won't tell you if a system is full or low. The pressures will change based on evap temperature and ambient temperature.
The best way for you to check the freon level is to check the sight glass that is on top if the receiver tank.
My Dolphin is a 2004 but yours may be the same. The receiver is a small round tank that is mounted to the front of the frame just below the heater/evap.housing. There are two small hoses on the top of the tank, each coming in opposite each other. On the top of the tank is a small round dimple. If you scratch away the paint with your finger nail it will reveal the sight glass.

With the A/C on and the fan on high there should be no bubbles visible in the sight glass after the A/C has operated for a few minutes.. There may be bubbles in the sight glass as the compressor cycles.

The amount of freon and oil installed in the system is critical and under high pressure (150-225) so if you are connecting gauges without experience you could cause real costly problems.

I have found the best way to get cold air out of the dash A/C is to install a shut off valve in the heater hose inlet to heater to stop any hot water from entering the heater core and cancelling the effects of the evap.

Belgian · 05-18-2020, 09:22 PM

Slight correction. The receiver tank is located right below the radiator cap.

The picture is sideways, sorry

Belgian · 05-18-2020, 09:49 PM

Here is the heater shut off valve I installed. The valve was from Home Depot

This picture is sideways also. When I post it the picture is correct, but it shows up rotated. ?????

Azborn76 · 05-19-2020, 04:27 PM

Thanks for the help, I have done the same thing but with a gate valve instead of the ball valve you used. I have not checked the sight glass I will have to see if I can crawl under and get a visual on it.

Belgian · 05-19-2020, 05:55 PM

No need to crawl underneath, the sight glass can be seen through the front hood.

PSOUZA · 05-19-2020, 10:58 PM

Quote:

Originally Posted by Azborn76

Hello
I'm wanting to give my dash AC a tune up before a long road trip this summer through the deep south. I have a 2003 Dolphin 6355 on a 2002 W22 chassis. I have been trying to educate myself about how to use a set of manifold gauges to properly check the 134 levels. However I cant seem to find the low and high pressure ports.

THis copy of the Evans Tempcon service manual may be of some help. It contains practical info that is difficult to obtain elsewhere.

https://proairllc.com/pub/media/pdfs...ice_Manual.pdf

Phil