"amdx" wrote in message
...
On 12/9/2013 5:23 PM, Jon Elson wrote:
amdx wrote:


I have powered the motor and I find both of the connections
on the compressor have air pumped out. I think the center, larger
fitting is the main outlet to fill the tank. I don't understand the
second and the drawing doesn't help, because where it goes, I don't see
anything for it to attach to. There's nothing behind the pressure switch
as shown.


The standard scheme is there is a check valve at the tank.

Hi Jon,
Where does the check valve go in the pneumatic circuit?


The pressure
switch has two ports, one to sense, and the other to relieve
pressure in the compressor line so the compressor doesn't stall
the motor. The small port on the compressor head would be this
connection.
So, if you don't have a relieving-type pressure switch, there is no place
to connect the relief port. But, a relieving pressure switch is
a REALLY good idea, it makes the motor's job a lot easier.
When it is working right, you will get a big PFFFT every time the
switch turns the compressor off.If it keeps hissing, then the check
valve is gummed up or jammed.

Jon

Looks like I'll be ordering a new pressure regulator and check valve.
I need to check the diagram and see where the check valve is supposed to
be, I don't think there is one.
Thanks, Mikek


There must be a check valve or the unloader would empty the tank. It is
usually located in the inlet to the tank. The compressor output goes to a T
connector then to the check valve. The center of the T goes to the unloader.
The pressure switch connects to the tank directly.

Sometimes all this is integrated into the pressure switch.