[bikestuff]

   

Thanks for the pictures, Brad.  Here are some thoughts about how I perceive the system to work.   If anyone has other ideas, chime in please!

Here is what I see…though I am not sure I really understand it.

The compressor is connected to the inlet of the solenoid.
The outlet goes to a check valve which goes to the rest of the plumbing.

Cautions:
- Be sure you are careful around 120VAC.  If you dont feel comfortable with these tests, get a technician to perform.
- Be careful around the air fittings.   I once tried to slightly undo an air fitting to release the air….when I got the fitting kinda loose, it shot out like a bullet and released all the air from the system at once.  I was inches away and it was LOUD.    Don’t be like me.

Assumptions which should be verified:
-  The leads on the solenoid have 120VAC when the compressor is running.
-  The leads on the solenoid DO NOT have 120VAC when the compressor if off.
-  The well switch turns the compressor off and on at appropriate air pressures.

How it the unloader system solenoid works…

1.  With the compressor OFF, The outlet port is connected to exhaust.  Which means there is no pressure in the air line between the outlet and the check valve.   Pressure remains between the inlet and the air compressor.

2.  With the compressor ON, the inlet port is connected to the outlet port.  The pressure will activate the check valve and air will flow to the rest of the plumbing.

Transitions…
3.  When the compressor turns OFF, the solenoid will return to the normally closed position.  In the normally closed position, the outlet is connected to the exhaust.  This releases the pressure from the outlet to the check valve which causes the check valve to close.  

4.  When the compressor turns ON, the solenoid will connect the inlet to the outlet, releasing any pressure in the line between the output of compressor and inlet to solenoid.   This will “unload” the compressor and allow it to start more easily.  As pressure builds, the check valve will open.

Tests…

1) with compressor off, verify that there is no pressure in the line between the output of solenoid and the check valve.   You should be able to blow into the outlet line and hear the air come out the exhaust.

2) with the compressor off, verify that you cannot blow into the inlet side of solenoid.  In the normally closed position, input of solenoid is capped, and outlet is connected to exhaust.

3) apply 120VAC to solenoid.  You should be able to hear a “click” and the inlet should be connected to the outlet.   You could use the on off switch on the well pump switch to do this.  1. Turn compressor off. 2.  release air in the system using quarter turn valve.  3. Disconnect the air line from compressor and the check valve.   4. Turn on well pump switch turning on compressor.  Blow into line going to inlet and see if air makes to out of solenoid on line going to check valve.
 
Thoughts:
-  If check valve gets stuck closed, the compressor can run but not provide air to system.

-  If the solenoid fails to operate it will block air pressure from the compressor to the rest of the system.

-  If the solenoid gets stuck in the “on” position, the compressor will have a hard time starting because there is no unloader circuit.

- Also, You might want to think about extending the line between the solenoid and the check valve.  Maybe put another foot of tubing in a loop.   This will create more air volume to unload the compressor making it easier to start and run.  

Bill