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MV & LV SERIES ENGINEERED DRY CHEMICAL FIRE EXTINGUISHING SYSTEM
OPERATION, DESIGN, & SERVICE MANUAL
REV C
Document # DOC324
Issued: April 26, 2018
Revised: March 22, 2022
UL FILE # EX27541
Section 2 System Components and Description
2.2.2 Low-Pressure Supervisory Switch Assembly
P/N 22946 (See Figure 2.2.2)
e low-pressure supervisory switch assembly continuously monitors the pressure within the cylinder. Should
the cylinder pressure drop to approximately 440 psi (30.3 bar), the switch contacts will close transmitting an
abnormal signal to the system control panel. e contact configuration is single pole, single throw (SPST)
with contacts rated 1.5 Amps at 24 VDC.
e low-pressure supervisory switch is fitted with a swivel nut and O-ring seal to allow it to attach to the
cylinder valve at the low-pressure supervisory switch connection. e low-pressure supervisory switch ports
of the cylinder valve contains a Schrader valve that seals when the switch is absent. e switch has 36 inch
(914 mm) leads. Refer to Section 4.1.4.2 regarding installation and removal of the low-pressure supervisory
switch assembly.
1.01 in
25.7 mm
2.97 in
75.4 mm
36 in lead
914 mm
Figure 2.2.2 Low-Pressure Supervisory Switch Assembly
O-Ring
(P/N 18582
1
)
1. O-Rings must be ordered in packs of 25 as P/N 98791
The Mv and Lv Series cylinder assemblies shall not be transported with the low-pressure supervisory switch assembly
installed. Remove the low-pressure supervisory switch assembly from the cylinder valve before transporting the
Mv Series or Lv Series cylinder assembly even if the contents are still under pressure. Refer to Section 4.1.4.2
regarding installation and removal of the pressure switch assembly.