I am starting a new thread based on a recent problem I have had, and a discovery that this affects at least one other coach, and my guess is there are more.
After picking up my coach at the factory in March, I drove 2,000 miles in cold weather. I could never get the heater to 'calm' down, and often opened a window. This was inspite of have max air set to cold. When I got to the warm Texas weather, I realized this was a big problem. I took the coach to my dealer complaining that I couldn't turn off the heater, and they replaced the evans valve at that time. They also discovered that I had 0 lbs in my AC, and sent me to Freightliner. FL charged the AC to 6lbs, which I found out was too much.
Newmar sent me to another Evans certified dealer to have the unit looked at, and they determined that I needed 4.5lbs of R-134a. The dealer claimed that the ac was blowing 40F air, and was fixed.
When I drove it home, the air started getting warm again. Finally I got a thermometer to test it, and discovered that as my water temp rose, so did the ac. Back to the valve.
There has been discussion on bad valves that Evans shipped around 2002-2004 (not sure on exact years), and 007 has information on that in this
link.
The problem that I am experiencing is different, and I have found at least 1 other coach that has the problem.
This is the evans valve that turns off the hot water supply from the engine. It is a one-way valve, meaning if it is installed reverse, it will fail. The plug end of the valve, on the left side, is the inlet (supply) side. It is oriented properly, but on mine it is installed on the RETURN line, and not the supply line.
This means that I have two problems. #1, hot water stays in the Evans unit, causing my AC to produce warm air all the time, and second, the valve is now receiving pressure on the wrong side, which will destroy the valve.
The new valve is now starting to fail again. Once it fails, it will allow the hot water to continuously circulate, and I am back to the original problem.
This was an installation error at the factory. The fix is to relocate the valve to the supply hose (shown above the valve), and replace the hose that is now too short. Since I am under warranty and this is clearly a factory error, that is what I am going to insist is done.
If I was not under warranty, as is the situation with the other coach I have seen this on, then the fix would be exactly what 007 did in the above post, but first relocating the evans unit to the correct supply line.
I am also attaching the evans troubleshooting guide
evtg.pdf, which discusses all the troubleshooting procedures.
I have sent all of this information to Newmar, because 3 attempts with dealers to fix the Dash Air have failed, and this forum was the only way I was able to finally figure out the issue. This included my most recent trip to a Evans Certified Service Center.
Hopefully this will help someone else in the future. If you have a 2013 coach, you should check this out while still under warranty. Your engine has to be at running temp in order to do a proper diagnosis.
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