[Richard]

Reese,

The engine air compressor feeds directly into the dryer. On the engine air compressor is a governor that sends a signal via a small air line to the dryer. That signal tells the valve on the bottom of the air dryer to "pop" or temporarily open. When it opens it exhausts any water that the dryer has collected, and it also relieves the pressure on the engine compressor. There is not a tank associated with the air dryer. It does feed the wet tank, but there is not a tank that is part of the air dryer.

The potential issue is that IF the valve is not behaving properly it may leave you with a situation where you cannot build air pressure. No air pressure means NO GO. The e brake would not release, and I think on later Newells there may even be a lock out that would prevent the tranny from going into gear.

I would definitely ask Newell about this. Your coach may be plumbed in a way that is different than what I have seen. It may be normal, and it may be a problem going somewhere to happen. I just can't say based on the info I have. Maybe some other guru with a coach of your vintage may be able to comment on their experience in providing external air.