Adding an auto Shut off to YongHeng PCP

It depends on which model you have. If yours is the basic model with no preset cut-out, you will need the relay as well. If you have the model that has auto cut-out that is preset but non-adjustable, It is just a matter of swapping the gauges and plugging the new wire into the same socket in the loom.

Personally I like to close my bottle/tank open the bleed valve on the compressor before shutting it down as it relieves pressure on the pistons, crank shaft etc.. I even let it run a minute or so to bleed out the water and cool off a bit.

Personally I like to close my bottle/tank open the bleed valve on the compressor before shutting it down as it relieves pressure on the pistons, crank shaft etc.. I even let it run a minute or so to bleed out the water and cool off a bit.

Click to expand...

YH has a check valve 

A check valve?

YH has a check valve with the auto shut off? Pretty sure the auto shut off dead heads the line and you have to bleed the lines after the fact.
(I could be wrong?)

YH has a check valve with the auto shut off? Pretty sure the auto shut off dead heads the line and you have to bleed the lines after the fact.
(I could be wrong?)

Click to expand...

There is a check valve on the inlet to the bleed block before the bleed screw. The set pressure or adjustable pressure switch does nothing but cut the power to the motor when the desired pressure is reached. I have the preset version and was toying with the idea of changing the gauge to upgrade mine to adjustable but after some consideration decided to just disconnect the switch and operate it manually. I don't think it is a good idea to just walk away and rely on the dodgy electronics to do their thing. I also don't want the thing to stop short of the pressure that I am happy to fill to because I like to bleed mine before shutdown. The reason that I do that is with my unit (others may differ) the separation block blow off valve vents loudly if I don't bleed it first. May be one of the check valves is not working properly. It doesn't make any difference to my fill times, so I don't worry about it. 

If you have the relay here is how it's wired. There are three black wires coming out of that middle connector one of them goes to the gauge. You can see the plug to the gauge in the background. As far as hooking it up goes it does not matter which one is red or black it's just a switch and switches don't care.

There is nothing here!

My Yong Heng has a red led with built in beeper that lights, locks out the motor and beeps until you shut it off. You can bleed it down but it will not restart without resetting.