Emerson Fisher 644 and 645 Handbook

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Fisherr 644 and 645 Differential Pressure Pump
Governors
Contents
Introduction 1.................................
Scope of Manual 1.............................
Description 1.................................
Specifications 2...............................
Educational Services 3.........................
Installation 3..................................
Direct-Acting Actuators 4.......................
Reverse-Acting Actuators 5.....................
Overpressure 6.................................
Startup 6......................................
Adjustment 6.................................
Principle of Operation 7.........................
Maintenance 7.................................
Disassembly 8................................
Reassembly 8.................................
Parts Ordering 10...............................
Parts List 10...................................
Figure 1. Fisher 644 Actuator Mounted on a Typical
easy-e™ Valve
W2265-1
Introduction
Scope of Manual
This instruction manual provides information on installation, adjustment, maintenance, and parts ordering for the
Fisher 644 and 645 differential pressure pump governors. Refer to separate instruction manuals for information about
the valve and other accessories used with these governors.
Do not install, operate, or maintain 644 or 645 governors without being fully trained and qualified in valve, actuator,
and accessory installation, operation, and maintenance. To avoid p ersonal injury or property damage, it is important
to carefully read, understand, and follow all the contents of this manual, including all safety cautions and warnings. If
you have any questions about these instructions, contact your Emerson Process Management sales office before
proceeding.
Description
644 and 645 actuators are used in combination with any of several sliding-stem valves to automatically control
steam-driven boiler feedwater pumps (reciprocating or turbine). The 644 or 645 actuator (see figures 1 and 2), when
used in combination with one of several push-down-to-close sliding-stem valves, forms a pump governor.
644 and 645 actuators may also be combined with push-down-to-open valves to be used as relief governors. Relief
governors are used to divert excess pump discharge back to the suction side of the pump.
Instruction Manual
D100302X012
644 and 645 Pump Governors
February 2014