any water flow to the Domestic Flow Port is diverted to
the Fire Sprinkler Flow Port.
The contours of the Piston have been specifically config-
ured to minimize its upward movement except under the
level of sustained fire sprinkler system flow resulting from
operation of one or more fire sprinklers. However, be-
cause most fire sprinkler systems contain air pockets, the
Piston will tend to move momentarily upward if there is a
surge in supply pressure. The momentary opening and re-
closing of the Piston at the Fire Sprinkler Line Seals will
trap a portion of the pressure increase within the fire
sprinkler system. The trapping of pressure increases
within the fire sprinkler system will help to reduce the pos-
sibility of a subsequent surge in the supply pressure from
causing the waterflow detector to signal a false alarm.
As indicated above, domestic system usage may reduce
the pressure available to the fire sprinkler system. How-
ever, when utilizing the S370 Valve, it is not necessary to
take into account the complex hydraulic modeling of the
domestic system that would otherwise be required to de-
termine the minimum possible residual (flowing) pressure
that would be available to the fire sprinkler system.
For operation of the S370 Valve, it is only necessary to de-
sign the fire sprinkler system, from the water supply main
to the most hydraulically remote sprinkler, to provide a
minimum single sprinkler flow of 5 GPM (19 LPM), when
the supply pressure at the main is at its minimum ex-
pected value. Actual sprinkler demand for the most hy-
draulically remote fire sprinkler should be in accordance
with the manufacturer’s minimum acceptable flow and
pressure, but the minimum flow must be at least 5 GPM
(19 LPM).
DESIGN CRITERIA
In order for the S370 Valve to automatically operate once
a fire sprinkler operates, the fire sprinkler system from
the water supply main to the most hydraulically remote
sprinkler must be designed to provide a minimum single
sprinkler flow of 5 GPM (19 LPM), when the water supply
pressure at the water supply main is at its minimum ex-
pected value.
NOTES
The minimum single sprinkler flow rate of 5 GPM (19
LPM), required for use with the S370 Valve, does not
take precedence over any more hydraulically demanding
single or multiple sprinkler flow rates specified for the resi-
dential sprinklers being utilized.
INSTALLATION
The Model S370 Automatic Residential Domestic Shut-
Off Valve must be installed in accordance with the follow-
ing instructions:
NOTE
A fire sprinkler water supply connection to a public water
supply is usually subject to local regulations concerning
metering and backflow prevention requirements. Consult
with the local water authorities concerning local require-
STAR SPRINKLER INC.
Page 2
2-7.1.10
FIGURE 1
MODEL S370 AUTOMATIC RESIDENTIAL
DOMESTIC SHUT-OFF VALVE
4-5/8"
(117.5 mm)
4-9/16"
(115.9 mm)
5-3/8" DIA.
(136.5 mm)
3-3/4"
(95.3 mm)
9-3/16"
(233.4 mm)
5
2
3
7
4
1
FIRE
PORT,
2" NPT
SUPPLY
PORT,
2" NPT
DOMESTIC
6
PORT,
2" NPT
SPRINKLER
WATER
NO. DESCRIPTION . . . . . QTY.
1
Body . . . . . . . . . . . 1
2
Cover . . . . . . . . . . 1
3
Piston . . . . . . . . . . 1
4
Spring . . . . . . . . . . 1
5
Fire Sprinkler Line Seal . 2
6
Domestic Line Seal . . . 1
7
Cover O-Ring . . . . . . 1
FIGURE 2
TYPICAL INSTALLATION
OBSOLETE
