Automatic Residential Domestic
Shut-Off Valve, 2 Inch (50 mm)
Model S370
GENERAL DESCRIPTION
The Star 2 inch (50 mm) Model S370 Automatic Residen-
tial Domestic Shutoff Valve is intended for use in dual-pur-
pose residential water supply piping that serves both do-
mestic and NFPA 13D or 13R residential fire protection
sprinkler system needs. When an automatic fire sprinkler
operates, the S370 Valve will automatically shut off water
flow to the domestic system and divert the available water
supply to the fire sprinkler system. Consequently, when
the S370 is utilized, the system designer need not add
the domestic flow demand to the fire sprinkler system
flow demand, as would otherwise be required by NFPA
13D or 13R.
Use of the Model S370 Automatic Residential Domestic
Shutoff Valve should be considered when either the water
supply cannot adequately provide for both the domestic
design demand and fire sprinkler flow demand, or it is de-
sirable to increase the effectiveness of the fire sprinkler
system by automatically shutting off domestic flow.
The S370 maximizes the effective use of a limited water
supply. It may eliminate the need to add costly pumps,
pressurized reservoirs, or electrically operated domestic
shutoff valves. The S370 has a built-in check valve in the
fire sprinkler system outlet that eliminates the need for a
separate check valve. Also, the S370 automatically resets,
thereby eliminating the need for valve disassembly after a
fire sprinkler system test or operation.
WARNING
The Model S370 Automatic Residential Domestic Shut-
Off Valve described herein must be installed and main-
tained in compliance with this document, as well as with
the applicable standards of the National Fire Protection
Association, in addition to the standards of any other
authorities having jurisdiction. Failure to do so may impair
the integrity of this device.
The owner is responsible for maintaining his fire protec-
tion system and devices in proper operating condition.
The installing contractor or sprinkler manufacturer should
be contacted relative to any questions.
TECHNICAL DATA
Approvals
UL and C-UL Listed.
Maximum Working Pressure
175 psi (12.1 bar).
End Connections
2 inch NPT
Friction Loss
Refer to Figure 4.
Physical Characteristics
The body, cover, and piston are bronze, and the piston is
Teflon
†
coated. The fire sprinkler line seals and domestic
line seal are silicone rubber, the spring is stainless steel,
and the cover O-ring is Buna-N.
OPERATION
The design of the S370 Valve is such that if there is a fire
sprinkler operation during domestic usage, the S370
Valve will automatically shut off flow to the domestic sys-
tem and divert the available water supply to the fire sprin-
kler system. This eliminates the lower flow into the sprin-
kler system that might otherwise be caused by possible
significant domestic water usage.
When the S370 Valve is in the normal standby position as
shown in Figure 3, the Piston, assisted by the Spring, is
in the down position. With the Piston in the down position,
the Fire Sprinkler Seals permit the S370 to perform as a
conventional check valve. Also, with the Piston in the
down position, water is available on demand through the
Domestic Flow Passage and out the Domestic Port.
Upon operation and a minimum 5 GPM (19 LPM) water
flow to the automatic residential fire sprinkler system, the
Piston moves upward. With the Piston in the up position,
414-570-5000 • 800-558-5236 • FAX 414-570-5010
6-99
2-7.1.10
STAR SPRINKLER INC.
E-mail [email protected]
#4200
†
D
u
P
ont
R
e
g
istered
T
ra
demar
k
OBSOLETE
