Dash a/c

[hapyhrs]

I have a 1999 38' Dutch Star diesel pusher on a Sparton Chassis and a Cummins 300. My dash a/c is not cooling like it should and I suspect it is low on freon. However the a/c data plate which is mounted on the evapator does not have the freon capacity listed. I would appreciate hearing from anybody that knows the system capacity or have a Newmar of similar size, year and model that has the freon capacity listed on their data plate.

[Clonetrooper]

Most a/c systems have a sight glass in the high pressure or smaller line that goes into blower housing behind front hood . If you add freon slowly with a/c running until most of the bubbles go away this is a full charge. If your system was completely empty then you would need a full charge.

[Midniteoyl]

Its loaded by pressure..Most systems are ~ 34psi on the low side.

Thus the little gauges on the refill bottles..That gauge goes from ~25 to 40psi and since you cant really trust them to be accurate, I like to fill it till its about 1/2 to 3/4 the way into the 'Normal', then let it run for 10 mins to see how cold it gets. Add a little more as needed. NEVER let it go above 45psi though, as it may start to freeze up..

The only way that knowing the charge capacity helps is when the system needs to be fully evacuated and refilled.

[ronsmith]

Hope i'am not to late, i have a 40 - 07 kountry star, the dash air holds 3 lbs. If you try to fill the freon using the sight glass method, it will take 6 lbs and your high pressure side is out of sight at low idle. Spartan recently changed the high idle switch to 240 lbs from 360 lbs. I had a leak at the compressor high pressure line, probably caused by running to high a pressure

[Iron Man]

If you can't put guages on the system and check high and low pressure at the same time and know how to read them--take it to a professional. You cannot go by a sight glass. Just because there is no cold air or bubbles doesn't mean you add freon. Ac systems can be tricky and having too much freon can cause more problems than not enough freon.

["007"]

Welcome ronsmith to the Newmar forum & irv2.
Thanks for your first post enjoy the forums and do post often.

[capt Frank]

My 1999 DSDP was not cooling well but after much looking found the hot water control for the heater was the culprit. I crawled under the engine and turned off the hot water to the heater and the ac went right to work as expected...the valve is quite pricey from Newmar so have been looking for a substitute.

[lonestarace]

We have a 98 DSDP on Spartan w/300 Cummins.

When I bought it 2+ yrs ago it wasn't blowing cold enough. Since I have my own ac vacuum pump and gauges, I evacuated the system then recharged it w/4 Lbs of R134 freon using the ac gauges. It blows 40-50 degree air now on 90+ degree humid days.

We hope this helps

Don