Bell & Gossett A91590B DB-3/4″ Differential By-Pass Valve 3/4″ x 3/4″ NPT Male Connections Operational Limits - Manual (Page 2)

INSTALLATION INSTRUCTIONS
(cont'd)
INSTALLATION INSTRUCTIONS
(cont'd)
The by-pass valve should be installed after the pump between
the supply and return piping. It can be installed either in the hor-
izontal or vertical position provided it is in accordance with the
direction of flow as indicated by the arrow on the valve body
(see Figure 1). With all valves open, set the bypass valve to
maximum pressure (clockwise). Gradually open the bypass
valve (counterclockwise) until flow begins in the bypass valve.
Increase the pressure setting by 1/2 to 1 psi or turn knob clock-
wise 1/2 revolution so the water stops flowing through the
bypass valve.
OPERATING INSTRUCTIONS OPERATING INSTRUCTIONS
Turn the knob to the desired value of the graduated scale; the
values correspond to the discharge pressure of the pump. Lock
the setscrew located on the knob.
CAUTION: Make sure that all the connecting pipework
is water tight.
CAUTION: If the by-pass valve is not installed, com-
missioned and maintained properly, according to the
instructions contained in this manual, it may not operate cor-
rectly and may endanger the user.
SERVICE INSTRUCTIONS
There is no service required for the differential by-pass valve.
CAUTION: Corrosion or leakage of the differential by-
pass valve can cause damage or injury, Periodically
inspect the differential by-pass valve for signs of leakage or
corrosion. If noted, the differential by-pass valve must be
replaced. Failure to follow these instructions could result in
property damage and/or moderate personal injury.
CAUTION: Overtightening and breakage can occur
with the use of PTFE pipe joint compounds. PTFE
provides lubricity so that care must be exercised not to over
tighten joints. Failure to follow these instructions could result
in property damage and/or moderate personal injury.
TYPICAL INSTALLATION
FIGURE 1
Xylem Inc.
8200 N. Austin Avenue
Morton Grove, Illinois 60053
Phone: (847) 966-3700
Fax: (847) 965-8379
www.xyleminc.com/brands/bellgossett
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© 2012 Xylem Inc. A91590B October 2012