Service Instructions
Backflow prevention assemblies must be drained for the winter
in areas where freezing temperatures may occur. If water inside
the assembly should freeze, damage to the assembly and the
system may occur. Proper draining procedures, insulation from
freezing using heat tape, and heated protective enclosures are all
methods of freeze protection.
In order to drain an assembly to prevent freezing, several import-
ant points must be remembered:
1 The assembly can not be adequately drained through the
testcocks. For proper draining follow the instructions detailed
in the drain procedures section.
2. Drain valves must be added on the inlet side and outlet side
of the assembly below the assembly (preferably below the
freeze line if the remainder of the system is to be drained).
3. Compressed air of adequate volume may be used to “blow-
out” the system after the backflow preventer is drained.
4. After removing water from the system and assembly, the
assembly shut-off valves, drain valves and testcocks should
remain in a half open / half closed (45o degree) position to
allow for full drainage of the ball valve shutoffs. If the assem-
bly is installed with ball valve shut-offs, see draining proce-
dure for ball valves on the reverse side of this sheet. The
main shut-off to the system must remain closed during the
winter period.
Draining Procedure
To drain the backflow prevention assembly for protection against
freezing, use the following procedures:
1. Turn off the main shut-off valve (A) which provides water to
the system.
2. Open all inlet and outlet drain valves on the system (B and E).
NOTICE
For any indoor drain valves, ensure that any water draining from
the system is collected to avoid water damage. Open inlet and
outlet shut-off valves on backflow prevention assembly (C and D)
and all testcocks. After fully draining system, leave in half open /
half closed (45o degree) position to allow for full drainage of ball
valve shutoffs. (See the ball valve freeze protection instructions
for more details.)
3. Should you “blowout” the piping system downstream of the
backflow prevention assembly, make sure the outlet drain
valve (E) is open and the backflow prevention outlet shut-off
valve (D) is closed.
4. Connect an air line to the outlet drain valve (E) and introduce
air of adequate volume to clear downstream system of water.
5.
NOTICE
Open outlet shut-off valves to the backflow
preventer assembly (C and D) to a half open/half closed (45°
degree) position after “blowout” procedure is complete.
6. Leave all drain valves (B and E), testcocks and ball or gate
valves to backflow preventer (C and D) in a hall open / half
closed position for the winter to prevent freezing.
NOTICE
When finished, make sure main shut-off valve (A) remains closed
to prevent accidental refilling of the system. AIso, the main shut-
off valve should be resilient seated to prevent see page of water
into the system.
E
Outlet
Drain Valve
D
A
Main Shut-Off
Valve
B
Inlet Drain
Valve
Valve Pit
C
Instructions for Installing
Model 765
Pressure Vacuum Breaker Draining
Procedure for Freeze Protection
IS-F-765-Winterization
WARNING
!
Read this Manual BEFORE using this equipment.
Failure to read and follow all safety and use information
can result in death, serious personal injury, property
damage, or damage to the equipment.
Keep this Manual for future reference.
Local building or plumbing codes may require modifica-
tions to the information provided. You are required to
consult the local building and plumbing codes prior
to installation. If the information provided here is not
consistent with local building or plumbing codes, the
local codes should be followed. This product must be
installed by a licensed contractor in accordance with
local codes and ordinances.
WARNING
!
