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2
Basic Installation Instructions
Installation Note:
The flange gasket bolts for the
gate valves should be retight-
ened during installation as the
bolts may have loosened due to
storage and shipping.
Check with local authorities for installation requirements. If
installing on a fire protection system be sure to purge air
from the system. Fill system slowly with all inspector test
valves open.
Pipe lines should be thoroughly flushed to remove foreign
material before installing the unit. A strainer should be in-
stalled as shown, ahead of the backflow preventer to prevent
discs from unnecessary fouling.
CAUTION: Do not install a strainer when backflow preventer
is used on seldom-used water lines which are called upon
during emergencies, such as fire sprinkler lines, etc.
It is important that Series 775 be tested periodically in compli-
ance with local codes, but at least once a year or more often,
depending upon system conditions.
775 Series for Retrofit Installations
Watts 775
12” min.
Refer to
Local Codes
Vault Installation
Vertical Flow
Up
12” min.
Refer to
Local Codes
Watts 775
Watts Series 775 Double Check Valve
#2 Test Cock
#3 Test Cock
#4 Test Cock
Outlet
Shutoff
Valve
Second Check
First
Check
#1 Test Cock
Inlet
Shutoff
Valve
