A/C Questions

[poorfarmer]

can't seem to get my vent temps below 55 degrees on my dash air. have vacuumed the system and re-installed the freon. on a 90 degree day at idle my readings are about 360 on the high side and about 35 on the low side. electric cooling fans are working properly. temps dont change at highway speeds so i dont think its a cooling issue. just wondering if i should replace the dryer and orifice tube and re-charge or not. also wondering if i should put in some cut-off valves on the heater core lines. if anybody has any ideas please run them by me. i have a 04 bounder

[TXiceman]

Make sure you have no heat going through the heater core and the dampers in the duct are in the proper position. Check you refrigerant level and pressure with the engine at a high idle (1000 to 1200 RPM) and dash fan on high speed.

I would shoot for 35 to 40 PSIG on the suction and 200 to 250 PSIG on the discharge in the summer. 360 PSIG sounds awfully high for R134a unless you are not getting enough air over the condenser. Can you use a box fan and set it up to blow some more air over the condenser? Do you have an infrared temperature sensor and can get some temperature reading on the compressor suction line, discharge line and the liquid leaving the condenser as well as the temperature on both sides of the drier. If you are seeing a temperature drop across the drier, it may be plugged.

When you had the system open, how well and how long did you run the vacuum pump on it?

HERE is an R134a pressure temp chart. The evaporator pressure should be about 40 to 45 deg F saturated and the condenser should be about 20 to 30 deg F over the ambient air.

Ken

[poorfarmer]

thanks txiceman i will check everything you suggested will let you know the results. thanks again

["007"]

This thread will explain why there have been problems with the EVAN's CONTROL VALVE. Notice dates of threads.

Many of us have added a ball valve in one of the heater hoses to keep the hot water out getting by the Evans valve. You can squeeze a heater hose with vice grips for a quick check.
The Evans valve is to the left of top hose.

[edgray]

Roger: I sure what you did works well, and your picture and advice have solved the problem for lots of folks. I have always been courious to know why you chose to install the Brass ball valve after the heater core instead of prior to the Evans valve.

Wouldn't stopping the hot water before the Evans plastic ball valve be preferable?

Ed

[az bound]

Evans had a bad batch of valves and your model year falls within that timeframe. You might contact Evans as they replaced ours free of charge.

[woodyk]

With 134a you should have 40 to 50 on the low side and around 200 high side. I just had to add to mine and found out my low side pressure cutoff switch was leaking. For everyone info the GM #10242579 and it doesn't cross over at the local auto parts store so I went up the internet and it's an AC Delco 15-2915.

Woodyk

["007"]

ED, as long as you stop the flow it seems to work on either hose. Have installed on others for people and works the same either hose.
Sometimes my wife tells me its to cold up front it works so good.
Heater still works as long as you do not forget to open the valve which I have been reminded of also.

[DriVer]

Originally Posted by "007"

Heater still works as long as you do not forget to open the valve which I have been reminded of also.

Roger, Are you saying that you have one of those nag-a-valves?

[Full-Timers]

Another problem is the intake for the air is situated so it will suck hot under hood air. I always run my dash air in the MAX mode which recalculates already cooled cabin air.

The Workhorse dash AC system is a POC. Workhorse agrees since they sell an after market kit called the Crystal Air™ kit.
http://www.irv2.com/forums/f57/workh...ing-14190.html

[tropical36]

Is there anything on a Motor Coach as a whole thats more troublesome than the dash air. I wish mine had never been installed in the first place with less junk to haul around.

[dagray]

I have had the dash air compressor replaced twice and it still does not get as cold as my 2002 Saturn. I have had it check many times and they tell me that is as good as it gets.

[ChrisNiemann]

just had to kick my 1993 over to 134a.... never seen the new tips put right on the back of the compressor before but thats the only place it fits so thats where they went! lol now just to put in a valve on my heater lines and go get her sucked down!!

as for where to put the valve, it doesn't matter where you put it, eventually it "stops" the flow of water from circulating so it doesn't really matter where you put it, i prefer to put it as close to the "forced water" side as possible so as to have a heater core blow out, you can kill the water right away and not make a mess or lose all your coolant!! just my .02

my hardest thing... finding a dryer for it! Oreilley's has a "P30" on its model list but the dryer didn't look the same for my setup, took old dryer off to have them look at it and on the back side was the sticker still on it that said "134a Dryer Only" lol so i put it back! other downside... i have no orifice tube or the "krimp" of where it goes... so i don't have one, hope not to many problems! anyone else not have an orifice tube in their 134a upgrade?

[dagray]

I have had my motorhome at an air conditioner place for three weeks. Yesterday they threw up their hands and said, we can not fix it you have to take it somewhere else. this is a place that does a lot of big trucks so I thought they could fix it.

On max air freeway speed if the inlet air is 75 degrees the air coming out of the dash is 70 degrees. Not much in the way of cooling. The line under the hood gets cold. I thought it was the Evans valve but they claim it is not. I called another air conditioning place who specializes in motorhomes and he does not know what an evans valve is. Claims it can't be that.

Compressor replaced, expansion valve replace. Vacuum and recharged three times and still the same. All at three different places. I wish I had a Ford Chassis.