Watts 774 - Manual (Page 3)

3
Installation
A. Series 774 may be installed in a horizontal or vertical flow up
position. The shutoff valve with the test cock is to be mount-
ed on the inlet side of the backflow preventer. The test cock
is on the inlet side of the shutoff valve.
B. The 774 should always be installed in an accessible location
to facilitate testing and servicing. Check state and local
codes to insure that the backflow preventer is installed in
compliance, such as the proper height above the ground.
The backflow preventer must be supported and is not de-
signed to carry full weight of the stand pipe.
C. Backflow preventers should never be placed in pits unless
absolutely necessary and then only when and as approved
by local codes. Consult your local or state plumbing or health
inspector. Watts recommends installation indoors or above
ground in an insulated enclosure.
Start Up
D. The downstream shutoff should be closed. Open upstream
slowly, fill the valve and bleed the air through Test cock 2,
3 and 4. When valve is filled, open the downstream shutoff
slowly and fill the water supply system. This is necessary to
avoid water hammer or shock damage.
E . Two or more valves can be piped in parallel (when approved)
to serve a large supply pipe main. This type of installation is
employed where increase capacity is needed beyond that
provided by a single valve and permits testing or servicing of
an individual valve without shutting down the complete line.
The number of assemblies used in parallel should be deter-
mined by the engineer’s judgement based on the operating
conditions of a specific installation.
Above Ground
Parallel
Watts 774
* For additional information on Watts insulated
enclosures send for ES-WB or ES-WBT.
*Insulated Enclosure
Watts 774
12” min.
Refer to
Local Codes
12” min.
Refer to
Local Codes
Installation Instructions
Watts Series 774