Larry, the wet tank and the front brake tank are the two at the front. Typically the wet tank, the one that receives air from the air compressors, is closer to the front and mounted lower (at least on the early 1990's models). The large tank in the rear is the rear brake tank. The small tank near the drive axle is the auxiliary tank for the air toilet if the coach is configured such that the toilet is not located directly over the waste holding tank and in later models with air-pocket doors supplies air to operate them. Additionally there are rectangular air tanks that feed the leveling system.
What does each tank feed? The front brake tank ONLY supplies the front air brakes. The rear brake tank ONLY supplies the drive axle and the tag axle brakes. At least on your coach, the small tank ahead of the drive axle typically feeds the air toilet and if equipped air-operated pocket doors. That tank is filled by the 12 volt air compressor and likely has a line from the wet/supply tank as a secondary feed with a check valve in the line. The supply tank feeds everything, the brake tanks, the leveling system tanks, the air-powered slides for the generator and slides in any of the bays, air-sealed slide-out bladders in coaches with slide-outs, the air powered slide over the steps and air-toilet if so equipped, the air-ride drivers seat, air-operated pocket doors in coach after about 1993, and in later models (some as early as 2000 year models) the Bode air-powered entry door.
The smaller tanks are all filled from the wet/supply tank. It is frequently referred to as the wet tank because it gets most of the moisture settling out in it and needs to be drained the most frequently since the engine air compressor and 120 volt air compressor feed directly into it. Air dryers maintained in good condition will help eliminate much of the moisture getting into the wet tank. If you have the 12 volt auxilary pump, you also need to maintain the drier on it as well as those for the engine compressor and the 120 volt compressor.
Since my coach doesn't have the air-toilet or air-pocket doors, I am sure that Richard can add to this discussion. The 12 volt pump and tank allow you to operate the toilet and air-pocket doors without having to keep the 120 volt pump operating. The supply tank will leak down due to the large number of fittings and connectors in the complex air system on a Newell. Wally is one of the few Newell owners that has spent the time and money to keep his tight enough to go for several days without the wet tank bleeding down significantly.
Once you are parked and leveled, assuming you don't have an air toilet or air pocket doors, slide bladders or air-entry door, you will likely not need to run the 120 volt pump unless you want to access the genset, move the step slide cover, re-level the coach or operate a bay air-powered slide.
Most of the air-operated items on the coach require 60 psi or more to operate. The air-toilet and air-operated pocket doors may be set to operate at about 45 psi but I will let those with more experience in their operation than I go into that.
|