Instruction Manual

Principle of Operation
The Type D34 is a direct-operated regulator. When
the water supply is cut in, the valve is in wide open
position. Water flowing to the system creates a rising
delivery pressure which feeds back through the control
ports to the underside of diaphragm (key 8). As the
pressure on diaphragm approaches a balance with the
force exerted by adjusting spring (key 5), disc (key 20)
is throttled to a position where just enough water flows
to maintain the set delivery pressure.
Installation
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WARNING
Personal injury or system damage
may result if this pressure reducing
valve is installed, without appropriate
overpressure protection, where service
conditions could exceed the limits given
in the Specifications section and/or
pressure reducing valve nameplate.
Additionally, physical damage to the
pressure reducing valve may result in
personal injury or property damage
due to escaping of accumulated gas.
To avoid such injury and damage,
install the pressure reducing valve in a
safe location.
All pressure equipment should be
installed in a non-seismic area;
should not be exposed to fire; and
should be protected from thunderbolt
(lightning) strikes.
• Carefully clear inlet piping system of foreign matter
and mount regulator with the flow arrow pointing in
the direction of flow.
• Preferred position for Type D34 valve is in a
horizontal line with spring chamber up. When so
mounted, the tendency of sediment to settle in the
control ports is practically eliminated.
• Provide a three-valve by-pass to facilitate
inspection of the reducing valve without
interrupting service.
• Avoid damaging effects of foreign matter in the flow
by using a strainer ahead of the valve.
Start-up
On starting up, follow these steps:
1. Open the inlet stop valve gradually until the
reducing valve takes control as indicated by the
delivery pressure gage.
2. Turn adjusting screw (key 1) clockwise to increase
the set pressure, counterclockwise to lower it.
Maintenance
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WARNING
To avoid personal injury, property
damage or equipment damage caused
by sudden release of pressure or
explosion of accumulated gas, do not
attempt any maintenance or disassembly
without first isolating the pressure
reducing valve from system pressure
and relieving all internal pressure from
the pressure reducing valve.
Pressure reducing valves that have
been disassembled for repair must
be tested for proper operation before
being returned to service. Only parts
manufactured by Emerson should
be used for repairing this pressure
reducing valve.
Due to normal wear or damage that
may occur from external sources, this
pressure reducing valve should be
inspected and maintained periodically.
The frequency of inspection and
replacement of parts depends upon the
severity of service conditions or the
requirement of local, state and federal
rules and regulations.
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Type D34