3. Adjust the pilot as needed. If the pilot is not piped
downstream, make sure the pilot exhaust is pointed in
the correct direction.
Shutdown
1. Close upstream block valve first and then close the
downstream block valve.
2. Open downstream and upstream vent valves
(not shown).
Pilot adjustment
The adjustment of setpoint (Figure 7), is performed
by means of the pilot adjusting screw, which varies
the compression of the control spring. Adjustment is
performed while the relief valve or backpressure regulator
is in operation with the aid of a pressure gauge to monitor
upstream pressure.
Loosen the Type PRX pilot locknut and turn the adjusting
screw slowly clockwise to increase set pressure and
counterclockwise to decrease set pressure. Use a
pressure gauge to monitor the set pressure until the
desired opening pressure is reached. When the desired
setpoint adjustment is completed and verified, tighten the
locknut to lock the adjusting screw in position.
!
Warning
avoid personal injury or damage to property
from sudden release of pressure or
uncontrolled gas or other process fluid. Before
starting to disassemble, carefully release
all pressures according to the appropriate
shutdown procedure. Use a gauge to monitor
relief (inlet) pressure while releasing it.
CaUTiOn
Use proper lifting techniques, when lifting the
upper and lower actuator casings (keys 11
and 5) off the Type EZH body (key 1). The
actuator assembly weighs more than 100 lbs /
45 kg.
Customer cannot use another type of eyebolt
in the regulator. Only Emerson parts can be
used to repair the unit.
Eye bolts are installed to aid in the handling
and installation of the regulator assembly
only. Do not attempt to lift more weight than
the regulator with these eye bolts.
Maintenance
Relief valve or backpressure regulator parts are subject
to normal wear and must be inspected periodically and
replaced as necessary. Due to the care Emerson takes
in meeting all manufacturing requirements (heat treating,
dimensional tolerances, etc.), use only replacement
parts manufactured or furnished by Emerson. Also when
lubrication is required, use a good quality lubricant and
sparingly coat the recommended parts.
The frequency of inspection and replacement depends upon
the severity of service conditions and upon applicable codes,
government regulations and company standards.
Use Torque Specifications (Table 3) for proper
torque values.
Polyurethane (PU) Disk Conversion
To convert Type EZH Relief units to a Polyurethane (PU)
disk from a Nitrile (NBR) or Fluorocarbon (FKM) disk, the
user will need to order three parts: disk retainer (key 31),
disk holder assembly (key 30) and seat ring (key 2). Please
contact your local Sales Office with any questions about
parts selection.
Main Valve and actuator Maintenance
Disk Maintenance
NPS 1 through 3 / DN 25 through 80 (Refer to Figure 4)
1. Remove nuts (key 26).
2. Carefully lift the upper actuator casing and lower actuator
casing assembly (keys 11 and 5) off the body (key 1).
3. Remove the hex socket cap screws (key 33) and lock
washers (key 32). Lift off the disk holder assembly (key 30)
and disk retainer (key 31).
4. Remove the O-ring (key 29). Inspect the O-ring for
damage or wear and replace if necessary. Lightly lubricate
O-ring before placing in the sleeve adaptor (key 27).
5. Remove the cage (key 3), seat ring (key 2) and O-ring
(key 34). Inspect the O-ring for damage or wear and
replace if necessary. Lightly lubricate O-ring before placing
in the body (key 1).
6. Set the seat ring (key 2) back in the body (key 1) with the
curved side down and the seat edge up. Place the cage
(key 3) on top of seat ring. The cage will engage the step
on the seat ring.
7. Place the disk holder assembly (key 30) and disk retainer
(key 31) on the sleeve adaptor (key 27).
8. Insert the lock washers (key 32) and hex socket cap
screws (key 33) and tighten.
9. Carefully lift the upper actuator casing and lower
actuator casing assembly (keys 11 and 5) and place
on the body (key 1). Secure with stud bolts and nuts
(keys 24 and 26).
5
Type EZH Relief
