Mooney Series 20 Relief Valve Instruction Manual | 5
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Product Introduction
Figure 1
Mooney Series 20 Relief Valve.
The Mooney Series 20 Relief Valve included in this manual is an
over-pressure protection device designed to be used with a self-
contained pilot valve system. This device is intended for use on
DOT regulated applications and shall NOT be used to meet the
requirements for ASME Section VIII.
The Mooney Series 20 Relief Valve consists of five main
components (Figure 1):
A. Main valve
Available in inlet sizes 1.5” through 8”, with a full-bore
orifice, the main valve contains a seat O-Ring to maintain
a bubble tight seal and a nozzle O-Ring to isolate the dome
from the inlet and outlet ports. Assembly and disassembly
of the main valve are accomplished through top entry. When
there is no pressure in the system, routine maintenance,
such as replacement of O-Rings and seals, may be done
with the main valve in place.
B. Mooney Series 20 or 20H Pilot in Back Pressure (BPV)
Mode
The Series 20 Pilot is an independent pneumatically
operated flowing auxiliary device intended for controlling the
main valve. While the Series 20 Pilot is able to be configured
in either pressure reducing or back pressure (BPV) modes,
it should only be used in the back pressure (BPV) mode
when installed on the Consolidated* main valve assembly.
C. Mooney Type 25 Restrictor
Designed exclusively for the Mooney Series 20 Relief Valve,
the Type 25 Restrictor has a variably controlled orifice with
a range setting of ‘0-5’. Adjustment of the restrictor affects
the response rate, stability, and sensitivity of the valve.
Smaller restrictor openings result in higher gain (sensitivity)
and slower closing speeds. Larger openings result in lower
gain (greater proportional band), greater stability and
faster closing speeds. The Type 25 Restrictor is required
for normal valve operation. The recommended and factory
setting for optimal performance is ‘2’.
D. Inline Filter
A 15 micron inline filter is recommended on all Mooney
Series 20 Relief Valves. This inline filter serves to limit debris
particles from entering the supply line of the pilot.
E. Field Test Connection
A field test connection is recommended for the Mooney
Series 20 Relief Valve. This allows the stroking of the valve
with an auxiliary media, e.g. air or nitrogen in order to
establish the desired pressure set point. An internal check
valve is present in the field test connection isolating the inlet
media from the test media and at the same time, allowing
the valve to open normally in the event of a system over
pressurization during a field test.
Specifications
Specifications
Main Valve Orifice
Full-bore
Sizes
1.5” (40mm) through
8” (200mm) inlet
Body Style
1.5” through 4” Inlet – Single Outlet
6” through 8” Inlet – Dual Outlet
Inlet Ratings
ASME/ANSI Class 150 through 300
Outlet Ratings
ASME/ANSI Class 150
Temperature Range
-20°F to 150°F (-29°C to 66°C)
Pressure Range
15 psig to 740 psig
End Connections
Raised-face flanges
Materials
Carbon Steel or 316 SST Main Valve
Brass or SST Pilot
Table 1
