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Dash Air Conditioning Troubles


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#1 dcatel

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Posted 07 March 2012 - 06:21 PM

I have a 2003 National RV 38 Ft Tradewinds on a Spartan Chassis, Cat 326 engine. Evans Tempco RV218467 Control Panel. For several years now the system loses its charge a couple of days after being recharged. The Compressor has been replaced; the dryer and I believe the expansion valve have been replaced. At least 3 different RV service outlets have worked on the problem. The system was flushed after the compressor was replaced. Each time the system is recharged with leak detector but the leak has not been found.

The last service organization said this was a common problem and that a number of customers just choose to either not attempt to find the problem or for very slow leaks just recharge the system every season. I want too resolve the problem once and for all, but don't want to spend another thousand dollars just looking.

Any ideas on how to cost effectively approach troubleshooting this problem. Or are some folks out there in the same boat, not able to use their dash air conditioning because of the potential expense of troubleshooting the system.

Thanks for any ideas.
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#2 wolfe10

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Posted 07 March 2012 - 06:44 PM

Have them add a leak detector dye when they next work on it.

Our dash HVAC works just fine and is 19 years old. You will have to determine the fix the dash A/C ($$$) vs use generator and overhead air ($$$) based on your needs.

Here is a typical product: http://www.oreillyau...N1786&ppt=C0050
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#3 BillO

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Posted 07 March 2012 - 07:14 PM

I've had the same experience with the dash A/C in my 17-year-old unit even though the major components were all replaced to upgrade to R134.

One tech pointed out that there is a lot of tubing (rubber, composite?) snaking from front to back in the DP's. If there is a leak along one of those lines there isn't any good way to see it even with the dye.

It seems to me that one could evacuate the system, disconnect those lines at the right point, plug them, then pressurize at the schrader valves to either isolate or rule out the lines as leak sources.

If the lines are the leak source, I'm not sure what to do as they are well buried in the coach chassis (at least in my case). However, you would at least know the cause.

If the lines prove not to be leak sources, then some more diligent work needs to be done around front and rear connections. One area that a tech found in my coach was a leaking weep hole on the high pressure connector to the compressor (that did not, however, solve my overall problem).
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#4 campcop

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Posted 07 March 2012 - 07:38 PM

I've had the same experience with the dash A/C in my 17-year-old unit even though the major components were all replaced to upgrade to R134.

One tech pointed out that there is a lot of tubing (rubber, composite?) snaking from front to back in the DP's. If there is a leak along one of those lines there isn't any good way to see it even with the dye.

It seems to me that one could evacuate the system, disconnect those lines at the right point, plug them, then pressurize at the schrader valves to either isolate or rule out the lines as leak sources.

If the lines are the leak source, I'm not sure what to do as they are well buried in the coach chassis (at least in my case). However, you would at least know the cause.

If the lines prove not to be leak sources, then some more diligent work needs to be done around front and rear connections. One area that a tech found in my coach was a leaking weep hole on the high pressure connector to the compressor (that did not, however, solve my overall problem).


That was my idea as well, the leak is most likely in a line and not in a major component if all have been either replaced or leak tested..
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#5 Icefixr66

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Posted 07 March 2012 - 10:33 PM

I have been told that the exsisting lines themselves leak due to the difference in molecular structure of r12,r22 and r134. Don't know how true this is but I have heard it from numerous people!
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#6 DickandLois

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Posted 08 March 2012 - 01:06 AM

This problem has turned up on a number of the larger PU trucks and some cars. That for the most part do not use the flexible lines used on Coaches. Not to say it is not possible with all the effort spent on how to save another dime.
The one item I have found to leak and not show any sighs of the dye are the valves in the High and Low pressure monitoring and charging points.
That little Schraeder Valve, like on tires. In this case the seal color for AC systems is Green. A little different compound because of the heat and cold range of the different sections of the system. They leak so slowly that it takes weeks to even months to see the reduced cooling effect, and the green dye is trapped under the caps. Not a sign of it on the exterior of the cap.
So,if you clean this area vary well with,something like spray contact cleaner, after it has been vacuum pumped, dyed( DO NOT OVER DYE OR OVER OIL) and recharged to the proper point.
Clean the caps the same way,put them on and forget it for a few weeks.
Then remove the cap, where it is a little dark at least, (not out in the sun) and shine a UV light at the area. (Black Light) if it glows it is leaking.
Considering the cost to recharge the systems along with time to vacuum pump, and other items needed is it worth it?
Should you live in an area of the country where you get an extended cooler season,then just before the hot weather arrives and the AC is not working anyway.Replacing the valve core at the time gets the best bang for your buck.
I loose about 8 to 10 oz. of 134 in my truck over 12 to 18 months and 6 to 8 oz. in the Coach (Motorhome)over the same period of time at present.

If you do change the core section, clean things VERY VERY well inside the stem area and the seal of the valve core. The smallest leek and the charge will slowly drop. If there is the smallest flaw in the set area its not ever going to completely seal.Then to replace the section(s)with the valve,is it worth $$$. ?
When one gets real lucky with the proper torque and cleaning and you reach 24 to 36 months, Well done my friend, Well done.

R.M.
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#7 dcatel

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Posted 12 March 2012 - 03:08 PM

Thanks to all who have replied. Certainly a couple areas that I need to check, which I do shortly. Any additional comments will be welcome.

Dave C
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#8 Allegiance40x

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Posted 16 March 2012 - 05:42 PM

dcatel...the bottom line to all the discussion is that you have a leak...period, regardless of what the techs are saying. We had a car like that, drove us crazy, EVERY spring the A/C did not work. Bottom line, it was a very tiny leak.
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