NGT, LLC. Understanding PO Check Valve Symbols

Check Valve Symbols

Check Valve Symbols and Meanings (yellow shading for easy reference)

Standard PO Check Valve,
no manual release
(e.g. B6M00, B8100)

Standard PO Check Valve
with manual release button
(e.g. A4M0M, B6M0M)

Adjustable PO Check Valve,
with manual release
(e.g. B6MFMAD)

Flow Control PO Check Valve,
no manual release
(e.g. BG4M00FL-1)

Pneumatic Counterbalance Valve,
with manual release
(e.g. B4MCFM, BG6MC0M)

Normally Open, Pilot to Close,
with Floating Check
(e.g. B6M00N0)

Dual Check Valve,
with manual release
(e.g. D6C0M, D4AS0M)

Dual Counterbalance Valve,
with manual release
(e.g. D6C0MC)

Check Valve Types	Symbol	Good For:
Standard PO Check Valves		Standard applications
Adjustable PO Check Valves		Quicker valve response if cylinder is drifting
Flow Control PO Check Valves		Reducing bounce, slowing down system
Pneumatic Counterbalance Valves		Preventing runaway for vertical cylinders with load
Dual Check Valves		Checking on both sides of the cylinder, in one valve package instead of two. Also reduces bounce. Great for horizontal applications
Vacuum Valves		Maintaining vacuum on a suction cup when supply is removed