[RussWhite]

Steve contacted me about getting additional details on the relay used to control the solenoid at the bottom of the auxiliary air water separator. I thought that would be an easy request to handle. Now I am plenty confused about how all the controls on my coach work together on this system.
My basic understanding is unchanged. That is, when the compressor runs, the solenoid on the separator is energized and it closes the valve so the water cannot drain out or the air escape. When the setpoint is reached and the compressor shuts down, the relay is de-energized, the power removed from the solenoid on the bottom of the separator, and the valve within is opened, letting the water and air drain.
What is confusing now is there are two ways to turn the compressor on, and that was a surprise. There is a pressure switch with contacts that turn it on, and there is a contactor in its own little box with the solenoid relay that will also turn the compressor on. Either one operates the relay correctly and air and water escape at the end of the cycle. It appears that the pressure switch is what starts and stops my compressor. If I manually close the other contactor it starts and stops as well. What I don't know is what might make the other contactor ever pickup. I just forced it closed with an insulated probe and the compressor ran. I actually expected it would close when the pressure switch called for air, but it didn't. If any of you know why there are two separate ways to run the 115vac auxiliary air compressor, please let us know.
The relay that controls the draining of the separator is a Potter and Brumfield general purpose relay P/N KHAU-17A18-120. It has four form C contacts, only two of which are used. The coil is 120VAC and gets power anytime the compressor gets power.
I have attached pictures.
Oh, one other mystery is the device just upstream of the pressure switch. It appears to be an adjustable air pressure regulator with nothing connected to the output port. You can see the adjustment on the pressure switch with its cover removed. Mine seems to start the compressor in the low 70's and stop it in the mid 80's.
Russ

[smagown]

Good post Russ.
Thanks,

[encantotom]

not to be surprising, but mine is different than russ's. i spent a ton of time when i rebuilt all of that trying to figure it all out. there is contactor like russ has, but not a relay like he shows. however, mine also has diodes and a wire from the leveling system to turn on the compressor.

i made sketchs of it all and when i get a chance will post them.

tom

[folivier]

On my '98 the pressure (well pump) switch controls the air compressor. But the HWH leveling panel also seems to turn on/off the compressor. If you're in manual leveling mode and press one of the UP switches the air compressor will turn on and off when you release the switch. Maybe that is what the other contactor is for?

[folivier]

My coach doesn't have the automatic water drain. It has a filter on the Gast air compressor with a manual release.
If I wanted to add this to mine would I just change the filter to one with a threaded fitting at the bottom to attach the solenoid, then add a check valve on the outlet of the filter?
Would it be ok to use a 120VAC NO solenoid and wire it into the compressor power wires so that it is powered up when the air compressor is running?
I'm assuming that the current the solenoid consumes would not affect the air compressor running?
My compressor is in the generator compartment and the controls are in the side compartment with the blower so it would be easier to wire it up at the compressor.

[smagown]

I just installed the separator like Russ and Tom have. I couldn't figure out how to wire it so I bought a $26 power supply off Amazon (step down transformer) that is 120v AC and comes out 12v DC on the other end. I wired the AC wires into the wires coming to the compressor where there were wire nuts. The DC end had a 12v receptacle on it and I cut it off and wired it to my 12V solenoid. It is only powered when the compressor is running so when the compressor cycles the 12volts cease and the valve on the bottom of the separator opens and it exhausts out the moisture. I wire tied the power supply to the upright under the compressor mount.Works fine so far.

[folivier]

Thanks to this post I finally found the elusive air leak I've been searching for.
The air compressor has been cycling every 30 minutes and finally saw 2 of the nipples on the water separating filter were leaking.
Pulled it all apart, cleaned off the teflon paste and used teflon tape to redo it. Now the compressor is cycling at 50 minutes.

[folivier]

I had planned to add the auto purge solenoid to my air compressor but ended up going in a different direction. I removed the SMC filter and installed this one I bought from Amazon:
http://www.amazon.com/gp/product/B0078SE...UTF8&psc=1
I also added a new check valve upstream of the filter. The filter does purge a little bit of air as the compressor is running but I think that's from the vibrations. So the compressor does run a couple minutes longer than it did each cycle.
Since I changed it my air compressor has gone from running every 30 minutes to every 3 hours or so. And it dumps the water automatically.

[qcj]

Forest, it just dumps it on the floor of the compartment? My compressor is in the gen. compartment. Can there be a hose connected to it where the water will dump on the ground?

[folivier]

Yes it does have a quick connection at the bottom for 3/8" plastic tubing. I bought some plastic tubing but haven't figured out how to route it yet.