Our policy is one of continued research and development. We therefore reserve the right to amend,
without notice, the specifications given in this document. © 2015 Norgren, Inc.
Simplified Valve Circuit Guide
2
Normally open 2-way valves pass inlet flow when unactuated and block flow when actuated.
Normally open valves can be applied to safety applications which require cooling flow, etc. when
actuated. Normally held off cooling flow would come on in event of failure.
Spring Return
Added to valve symbol. The spring returns the valve to its normal, unactuated position.
Air Operator
Simplified air operator added to the valve symbol. When the valve is actuated, the flow path shown in
the upper block replaces the flow path in the lower block.
Spool Valve, 3-Way, 3-Port, used as a N.C. 2-Way, 2-Port
To use a 3-way spool valve as a 2-way normally closed valve, plug port 3 and connect the inlet to
port 1 and the outlet to port 2
Spool Valve, 3-Way, 3-Port, used as a N.O. 2-Way, 2-Port
Except: The normally open, 2-way configuration is not possible with the 3-way 1/8" Nugget solenoid
operated valve. This valve does not have provisions for "Normally Open" solenoid operated valves.
N.O. 2-WAY
SYMBOL
ACTUATED
POSITION
UNACTUATED
POSITION
IN OUT
SPRING
RETURN
SYMBOL
N.C. 2-WAY
SYMBOL
IN OUT
SIMPLIFIED
AIR PILOT
SYMBOL
3-WAY
USED AS
N.C.
2-WAY
IN 1
2 OUT
3
12
10
3-WAY
USED AS
N.O.
2-WAY
3
2 OUT
IN 1
12
10
