Max Air No Temperature Control?

[fayrankin]

On a 2005 33V Adventurer on the Workhorse Chassis, I find that on MAX AIR (no outside air-recirculating inside air only) there is no temperature control. It just gets colder and colder. Most times you can solve the problem by just going to normal air but if you are in a bad environment and don't want to smell and breathe whatever is going on outside, this is a problem. I've talked to the factory and to the outfit that make the heat/ac unit and they say "yeah, that's the way it is." Has anyone figured out a way around this. Seems to me like a thermostat that would cut out the compressor might work but would probably be pretty "Mickey Mouse". I still have a hard time believing the system is really designed this way.

Thoughts; sympathy? Solutions!

[fayrankin]

On a 2005 33V Adventurer on the Workhorse Chassis, I find that on MAX AIR (no outside air-recirculating inside air only) there is no temperature control. It just gets colder and colder. Most times you can solve the problem by just going to normal air but if you are in a bad environment and don't want to smell and breathe whatever is going on outside, this is a problem. I've talked to the factory and to the outfit that make the heat/ac unit and they say "yeah, that's the way it is." Has anyone figured out a way around this. Seems to me like a thermostat that would cut out the compressor might work but would probably be pretty "Mickey Mouse". I still have a hard time believing the system is really designed this way.

Thoughts; sympathy? Solutions!

[oemtech]

First let me welcome you to IRV2.

Next I would suggest that you add some rig info to your signature so we can better answer your questions.

As for the Max Air issue. As far as I know the system uses hot water to regulate the temp. The system uses vacuum to control the doors for Normal air, Max Air and the Heater Control valve. From what you have posted I would suspect you have a bad Evans Tempcon heater control valve or possibly a vacuum leak.

Not sure who/whom you are referring to when you say "I've talked to the factory and to the outfit that make the heat/ac unit and they say "yeah, that's the way it is." and they obviously don't have a clue of how the A/C controls work.

[wilanddij]

You definitely have a malfunction in your temperature controls. I can adjust the temp when pulling either outside or inside air.

[fayrankin]

Thanks,

My Winnebago uses a heating AC system from Specific Climate Systems in Fort Worth, Texas. The owner's manual from them states the following: " In the MAX A/C mode, the TEMPERATURE CONTROL SWITCH will have minimal effect on temperature. Also MAX A/C operation is achieved using air recirculated from the coach interior."�

I also just came across a schematic for the vacuum system in a June '05 WIT Club News magazine that shows the hot water heater valve is closed in MAX A/C. "Yeah, that's the way it works"�

You are both right about how it SHOULD HAVE BEEN DESIGNED and I'm probably just stuck with a very stupid set up. I am curious as to who made the heat/cool system on your coaches. How is the temperature modulated on high cool? Possibly examination of the schematics would yield an answer for a simple modification to make it work like I wished it did. Meantime, I guess I'll check over at the Winny Owner's site and see if anyone has tackled the problem.