Watts 909 Series Basic Installation Instructions

Troubleshooting Guide - Backflow Preventers
Problem Cause Solution
A. Valve spits periodically from the vent.
A.1 Fluctuating supply pressure.
A.2 Fluctuating downstream pressure.
B. Valve drips continually from the vent
B.1 Fouled rst check.
B.2 Damaged or fouled relief valve seat.
B.3 Relief valve piston O-ring not free to move
due to pipe scale, dirt or build up of
mineral deposits.
B.4 Excessive backpressure, freezing or water
hammer has distorted the second check.
B.5 Electrolysis of relief valve seat or rst
check seats.
B.6 Valve improperly reassembled.
C. Valve exhibits high pressure drop.
C.1 Fouled strainer.
C.2 Valve too small for ows encountered.
D. No water ow downstream of valve.
D. Valve installed backwards.
E. Valve does not test properly.
E.1 Follow manufacturer’s test procedure
E.2 Leaky downstream gate valve.
F. Valve quickly and repeatedly fouls following
servicing.
F. Debris in pipe line is too ne to be trapped
by strainer.
G. Winterization of backow preventers.
A.1 Install a soft seated check valve immediately
upstream of the device. (Watts
3
⁄4" - 2" (20-50mm)
No. 601 bronze valve.)
A.2 Install a soft seated check valve downstream of
the device close as possible to the shutoff valve.
(Watts
3
⁄4" - 2" (20-50mm) No. 601 bronze valve.)
B.1 Flush valve. If ushing does not resolve problem,
disassemble valve and clean or replace the
rst check.
B.2 Clean or replace the relief valve seat.
B.3 Clean, grease or replace the piston O-ring.
B.4 Eliminate source of excessive backpressure or
water hammer in the system downstream of the
device. Use Watts No. 601 to dampen out back
pressure and No. 15 to eliminate water hammer.
Replace defective second check assembly. In
case of freezing; thaw, disassemble and inspect
internal components. Replace as necessary.
B.5 Replace relief valve seat or inlet cover. Install
dielectric unions (Watts Series 3001 through 3006).
Electrically ground the piping system and/or
electrically isolate the device with plastic pipe im-
mediately upstream and downstream of the device.
B.6 If valve is disassembled during installation, caution
must be exercised to install check springs in their
proper location.
C.1 Clean strainer element or replace.
C.2 Install proper size device based upon
ow requirements.
D. Install valve in accordance with ow
direction arrow.
E.1, E.2 Clean or replace gate valve with full port ball
valves or resilient wedge shutoff valves.
F. Install ner mesh strainer element in the strainer.
G. Electric heat-tape wrap closely together around
valve body. Build a small shelter around the valve
with a large light bulb installed and left on
at all times.
If supply line is not used during the winter, re-
moval of the complete body is the best. This
would create an air gap to eliminate any
possible backow.
7

Watts 909 Series Specifications

General

Series	909
Category	Control Unit
Body Material	Bronze
Connection Type	Threaded
Temperature Range	33°F-180°F
Size Range	1/2" - 2"
End Connections	Threaded