Flowserve H71 Series - Manual (Page 2)

6. Torque Requirements - Operating torque requirements will vary
depending on the length of time between cycles, line pressure,
type of valve seats, and the media in the system. For a detailed
analysis of valve torque requirements, see the Worcester Actuator
Sizing Manual.
MAINTENANCE
Tighten retaining nut if seepage is noted at stem.
CAUTION: For maximum stem seal life, proper stem adjustment
procedure must be followed. Excessive tightening causes
higher torque and shorter stem seal life.
For 1/2"–1 1/2" Valves with two Stem Nuts and a Lockwasher (Manual
Valves):
1. Tighten retaining nut (lower nut) until Belleville washers are flat,
the nut will “bottom”.
2. Back off retaining nut 1/6 turn.
3. Tighten top nut securely to lock retaining nut in place.
For 1/2"–1 1/2" Valves with Self-Locking Stem Nut and four Belleville
washers (Automated Valves):
1. Tighten self-locking stem nut until Belleville washers are flat, the
nut will “bottom”.
2. Back off 1/3 turn.
CAUTION: The self-locking stem nut is difficult to tighten, and
must fully flatten Belleville washers before backing off.
For 2" Valves
1. Tighten retaining nut 1/6 turn at a time until seepage stops.
REBUILDING
a WARNING: Ball valves can trap high-pressure fluids in ball
cavity when closed.
If the valve has been used to control hazardous media, it must be
decontaminated before disassembly. It is recommended that the
following steps be taken for safe removal and disassembly:
• Relieve the line pressure. Operate the valve prior to attempting
removal from line.
• Place valve in half-open position and flush the line to remove any
hazardous material from valve. (See Caution, page 1,
paragraph 2.)
• All persons involved in the removal and disassembly of the valve
should wear the proper protective clothing such as face shield,
gloves, apron, etc.
1. A standard repair kit may be ordered for these valves, consisting
of seats and body seals, two or four Belleville washers, stem
seals, and thrust bearings. Specify the material of seats and body
seals, size, Series and R number (revision number) of valve or for
non-standard valve, the “P”, “T”, “C”, or similar number, as found
on the valve nameplate or on the actuator bracket nameplate. If
valve body is stainless steel, place a “6” after valve size in repair
kit ordering code.
To Order:
Valve Size/HRK71/Material/Rev. Number or P, T, C, etc. Number
Example: 1" 6 HRK71 XV C0222
CAUTION: If the seats and seals installed differ from those
removed, the valve nameplate or stop must be replaced or
remarked to indicate the altered materials and ratings, or valve
tagged to so indicate.
2. To replace seats and seals:
a. Place valve in open position, remove all but one of the body
nuts and bolts, loosen remaining one, swing out center
section from between pipe ends with valve open.
b. With valve in closed position, remove old seats, body seals,
and ball.
c. For 1/2"–1" valves remove handle nut, lockwasher, one-piece
handle and stop (if manual valve). (This step is not applicable
to valves with self-locking stem nut.)
For 1-1/2" valves only, remove handle nut, lockwasher, one-
piece wrench/stop and extension (if manual valve). This step
is not applicable to valves with self-locking stem nut.
For 2" manual valves only, remove handle assembly (wrench
block and extension), by removing hex head screw.
d. Using handle or a wrench to prevent stem from turning,
remove retaining or self-locking stem nut, stop (2" manual
valve only, or stem spacer if automated valve), Belleville
washers (1/2"–1 1/2" only), and follower from stem. Remove
stem through body cavity.
e. Remove thrust bearing(s) from body or stem, stem seals, and
stem seal protector from recess in top of body.
f. Clean all sealing surfaces of valve including the ball.
NOTE: The ball and the surfaces against which the seats and seals are
installed should be undamaged, clean and free of pit marks and
scratches. Light marring from the action of the ball against the seats is
normal and will not affect the operation of the valve. Flaws which can
be seen but barely detected with fingertips are acceptable. The stem
and body surfaces that the thrust bearings and stem seals contact
must be undamaged, clean, and free from pit marks and scratches.
g. Lightly lubricate the ball, seats, body seals, stem seals, stem
seal protector, and thrust bearings with a lubricant compatible
Flow Control Division
Worcester Control Valves
2 14932-D