Backflow Preventor; Vacuum Breaker; Rp Device - GAYLORD CG Series Technical Manual

BACKFLOW PREVENTORS
Model GPC-5000 Series control cabinet uses a vacuum
breaker/check valve assembly for backflow prevention. Model
GPC-5000-RP Series control cabinet uses a reduced pressure
principle device (RP) for backflow prevention. Refer to Pages
26 through 28 for illustrations of each. The type of backflow
preventor used is dictated by state, county or city code.

VACUUM BREAKER

1. If the vacuum breaker leaks or "spits" either at the
beginning or the end of the wash cycle, check the
following:
A. Check to make sure the vacuum breaker is mounted
6" higher than the line going to the ventilator. (See
illustration on Page 26.)
B. Remove the top cap of the vacuum breaker and check
to make sure the nylon check valve slides up and
down on the guide stem properly, and that the stem
is straight.
C. Check to make sure that the rubber washer on top of
the nylon check seats properly against the
machined surface, and that the surfaces of both the
rubber washer and the machined surface are smooth.

RP DEVICE

The reduced pressure principle device (RP) is required to
prevent contaminated water from backflowing upstream to
potable water.
1. Initial Start-up-To avoid water hammer or shock damage
perform the following initial start-up procedures:
A. Close the outlet hand valve.
B. Open the inlet hand valve slowly, fill the valve and blend
the air through test cock number 2, 3, and 4.
C. When the valve is filled, open the outlet hand valve
slowly and fill the remaining supply system. The initial
start-up procedure is now complete.
The reduced pressure principle device type backflow preventor
(refer to Figure 22A & 22B) consists of two primary chambers
with spring loaded check valves and a secondary chamber
INLET HAND VALVE
FIGURE 22A
REDUCED PRESSURE PRINCIPLE DEVICE

BACKFLOW PREVENTOR

TROUBLE-SHOOTING
OUTLET HAND VALVE
with a spring loaded relief valve. This device prevents
backflow by opening and closing the check valves if the
pressure from the inlet side to the outlet side of the device
varies.
1. Intermittent Discharge - Intermittent discharge of
water through the relief valve is fairly common and usually
occurs if there is inlet pressure fluctuations of more than
3 psi and when the solenoid valve closes after a wash
cycle.
2. Continuous Discharge - If there is continuous
discharge of water out the relief valve when the ventilator
is not in a wash cycle, do the following:
A. Leave the inlet hand valve open and close the outlet
hand valve. If there is still continuous discharge it
indicates that foreign material is preventing the first
check valve from closing. If flushing will not clear the
unit, remove and clean the first check valve.
B. If there is continuous discharge of water out of the
relief valve during a wash cycle, there is foreign
material preventing complete closing of the relief
valve. Flushing the relief valve may correct this
condition.
Repeat procedure if necessary. If flushing does not stop
discharge with flow through the device, remove and clean relief
valve.
In no case should the relief valve outlet port be plugged, closed
off or restricted.
This device should be inspected occasionally for continual
discharge from the relief valve, which indicates a need for
maintenance. It is recommended that the RP device be
inspected and tested once a year.
NOTE: Some regulations require annual inspection and
testing by a company certified to perform such duties.
See Instruction Manual IS-TK-DP, obtainable from your Watts
installer or distributor. For the name of your nearest installer
or distributor, call Watts Regulator at (508)688-1811.
REDUCED PRESSURE PRINCIPLE DEVICE
BACKFLOW PREVENTOR
20
FIGURE 22B