Mooney Series 20 Relief Valve Instruction Manual | 13
Copyright 2021 Baker Hughes Company. All rights reserved.
Improper use or re-
pair of a pressurized
device may result in
severe personal injury
or death.
Improper tools or im-
proper use of the right
tools could result in
personal injury or
product damage.
Reassembly of Pilot to Main Valve
To replace, put Teflon thread tape on NPT nipple end and turn
pilot clockwise with nipple in connecting port until snug and
oriented properly. Reconnect all tubing - Refer to Figure 6 and
Figure 7 for orientation and tubing locations.
Mooney Series 20 Pilot
Product Description
The Series 20 Pilot is an independent pneumatically operated
flowing auxiliary relief valve intended for controlling the
Consolidated* main valve.
Series 20 -
Brass construction with 15 to 450 psi (0.20 bar -
31.02 bar) control pressure range.
Series 20H -
High pressure brass construction with a 200 to 750
psi (13.79 bar - 62.05 bar) control pressure range.
Series 20S -
Stainless steel construction with a 15 to 450 (0.20
bar - 31.02 bar) control pressure range.
Series 20HS -
High pressure, stainless steel construction with
a 200 to 750 psi (13.79 bar - 62.05 bar) control pressure range.
The parts in all constructions are interchangeable. The high
pressure construction (Series 20H and 20HS) varies from the
Series 20 and 20S with the addition of a diaphragm spacer
assembly that reduces the effective area of the diaphragm and
increases the spring range of the black and green springs.
General Description
(Figure 11)
1
Spring Housing:
The Pilot Spring Housing is provided with a 1/4
inch NPT vent connection which may be piped to a safe area or
pressure loaded for remote control of the pressure setting. The
Main Spring may be changed by simply removing the Closing
Cap (1A).
2
Body Insert Assembly:
A removable Body Insert Assembly
(cartridge), at the bottom of the Pilot Body, contains the inner
valve mechanism. The cartridge may be replaced with a spare
unit for fast trouble shooting or repair. The Body Insert Assembly
is also field repairable.
3
Inlet and Loading Ports:
The INLET port is common with
the LOADING port through an internal passage in the pilot. A
Restrictor must always be connected to the INLET port when
used with the Consolidated main valve. The LOADING port is
used to connect and mount the pilot to the dome chamber of the
main valve.
4
Sensing Port:
The SENSE connection is “static” which means
that there is no flow in the sensing line and the true pipeline
pressure is measured at the diaphragm.
5
Outlet Port:
The OUTLET port must be connected to the
valve outlet or outlet pressure system. The Series 20 Pilot has
separate SENSE and OUTLET connections. Separate SENSE
and OUTLET ports make piping easier.
6
Diaphragm Spacer Assembly:
The addition of this assembly
converts the Series 20 & 20S Pilot into the high pressure Series
20H & 20HS. It reduces the pilot diaphragm area and increases
the spring range of the black and green springs.
WARNING:
The pilot is designed for use with an external
restrictor (Principle of Operation Section). The restrictor must be
the Mooney Type 25 Restrictor and must be installed in the pilot
inlet connection (3).
