[Dave]

Art,

I was headed down the same path as you awhile ago with the opposite problem. (No Flow). I figured out during testing that the valve was fine. I had no flow because the valves on the engine coolant filter were closed. I still do not know why those valves have to be open but it definately solved my problem and that was as far as i went.

Its been awhile now but if i remember correctly you cannot us a 24vac valve on 24vdc. Something about inductive loads and heat and a bunch of other stuff i am not too proud to admit i do not understand. Perhaps one of the electrical guys can verify this. Also i seem to remember that the copper for that was 34 od heating tubing instead of 3/4 id plumbing.

Sounds like a viable work around since the dash heat does not seem to effect the overall climate in the coach very much. Off and on would be fine.i will use Jons disclaimer in that everything i said could be wrong. Just food for thought.

[Dave]

Doesn’t Prevost have a drop in replacement Norgren? If not you are going to have to figure out the valve paths with air to the pilot and no air to the pilot and describe it to a Norgren tech to find their match as far as air flow circuits.

If I remember correct the valve not only lifts the tag, it also disables the brakes on the tag axle.

[Dave]

Just commenting on what I think I understand and that is accessory pressure can leak back through the aux compressor, but that is why Liberty has a solenoid valve (and maybe a check valve) in the line from the aux compressor to the Liberty manifold.