Instruction Manual
September 2013
Type EZH
Type EZH Relief or Backpressure Regulator
TYPE PRX/182
Figure 1. Type EZH Regulator Figure 2. PRX Series Pilot
WARNING
!
Failure to follow these instructions or to
properly install and maintain this equipment
could result in an explosion and/or re
causing property damage and personal injury
or death.
Fisher® relief valve or backpressure regulator
must be installed, operated, and maintained
in accordance with federal, state, and local
codes, rules and regulations, and Emerson
Process Management Regulator Technologies,
Inc. (Regulator Technologies) instructions.
If the relief valve or backpressure regulator
vents gas or a leak develops in the system,
service to the unit may be required.
Failure to correct trouble could result in a
hazardous condition.
Call a gas service person to service the unit.
Only a quali ed person must install or service
the relief valve or backpressure regulator.
Introduction
Scope of the Manual
This manual provides installation, startup and maintenance
instructions, and parts ordering information for theType EZH
relief valve or backpressure regulator and PRX Series pilots.
Information on other equipment used with this product is
found in separate manuals.
Product Description
Type EZH relief valve or backpressure regulator is pilotoperated and designed for use in high pressure natural gas
transmission/city gate stations, large capacity distribution
systems, and power plant feeds.
Pilot Descriptions
The Type EZH relief valve or backpressure regulator
include a Type PRX/182 pilot mounted on the main valve.
PRX Series pressure reducing pilots have the ability to
handle a wide range of setpoints from 29 to 1160 psig /
2.0 to 80.0 bar.
www.fisherregulators.com
D103078X012
Type EZH Relief or Backpressure Regulator
Speci cations
Ratings and speci cations for the Type EZH are listed in the Speci cations section below. Speci cations for speci c relief
valve or backpressure regulator constructions are stamped on a nameplate attached to either the main actuator or the pilot
spring case.
Body Sizes, End Connection Styles, and
Pressure Ratings
(1)
See Table 1
Maximum Inlet and Outlet (Casing) Pressures
(1)
1500 psig / 103 bar
Maximum Emergency (Design Casing Pressure)
1500 psig / 103 bar
Maximum Operating Differential Pressure
(1)
Main Valve: 1500 psid / 103 bar d
Pilot (Between loading pressure in pilot and
loading sense pressure): 1233 psid / 85.0 bar d
Outlet Pressure Ranges
(1)
Pressure Registration
External
Pilot Connections
1/4 NPT
Temperature Capabilities
Nitrile (NBR) Version:
-20 to 180ºF / -29 to 82ºC
Fluorocarbon (FKM) Version:
0 to 180ºF / -18 to 82ºC
Options
• Pre-piped Pilot Supply
• Travel Indicator
See Table 2
Minimum Differential Pressures
MAIN VALVE
TYPE
EZH
1. The pressure/temperature limits in this Instructional Manual and any applicable standard or code limitation should not be exceeded.
2. Type PRX Fluorocarbon (FKM) elastomer is limited to 0°F / -18°C.
BODY SIZE
NPS DN psid bar d psid bar d
1 25 15.2 1.1 15.7 1.1
2 50 12.0 0.83 13.8 0.95
3 80 10.6 0.73 12.8 0.88
4 100 15.8 1.1 16.4 1.1
(1)
MINIMUM DIFFERENTIAL
For 90% Capacity For 100% Capacity
(1)
(2)
SPRING
PORT A
CASE VENT
PORT B
EXHAUST
PORT L
PORT S
M1055
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
LOADING PRESSURE
Figure 3. Type EZH with Type PRX/182 Pilot
2
Type EZH Relief or Backpressure Regulator
Table 1. Main Valve Body Sizes, End Connection Styles, and Body Ratings
MAIN VALVE BODY SIZE
NPS DN psig bar
1 25
2 50
3 80
4 100
MAIN VALVE BODY MATERIAL END CONNECTION STYLE
NPT or SWE 1500 103
CL150 RF 290 20.0
CL300 RF 750 51.7
CL600 RF or BWE 1500 103
NPT or SWE 1500 103
CL150 RF 290 20.0
WCC Steel
CL300 RF 750 51.7
CL600 RF or BWE 1500 103
CL150 RF 290 20.0
CL300 RF 750 51.7
CL600 RF or BWE 1500 103
CL150 RF 290 20.0
CL300 RF 750 51.7
CL600 RF or BWE 1500 103
STRUCTURAL DESIGN RATING
Table 2. Relief Set Pressure Ranges
PILOT
TYPE
PRX/182
PRX-AP/182 435 to 1160 30.0 to 80.0 GD27379X012 Clear 0.335 8.51 3.94 100 1160 80.0 1480 102
RELIEF SET
PRESSURE RANGE
psig bar Inch mm Inch mm psig bar psig bar
29 to 116
73 to 290
217 to 609
2.0 to 8.0
5.0 to 20.0
15.0 to 42.0
Part Number Color
GD25522X012
GD25520X012
GD25519X012
Black
Gold
Red
PILOT CONTROL INFORMATION
Wire Diameter Free Length
0.157
0.197
0.236
3.99
5.00
5.99
2.16
2.01
2.01
Maximum
Operating
Pressure
55
51
51
609 42.0 1480 102
Maximum
Emergency
Pressure
Principle of Operation
A pressure relief valve is a throttling pressure control device
that opens and closes to ensure the inlet pressure does not
rise above a predetermined pressure. Fisher® relief valves
cannot be used as ASME safety relief valves. A backpressure
regulator is a device that controls and responds to changes in
the upstream pressure. It functions the same as a relief valve
in that it opens on increasing upstream pressure.
Relief Valve
As long as the inlet pressure is below the set pressure, the pilot
control spring keeps the pilot valve plug closed. Inlet pressure
passes through the restrictor and registers as loading pressure
on the main valve diaphragm chamber. Force from the main
spring, in addition to pilot loading pressure, provide loading
pressure to keep the main valve diaphragm and plug assembly
tightly shut off. When the inlet pressure rises above the set
pressure, the pressure on the pilot diaphragm overcomes
the pilot control spring and opens the pilot valve plug. The
pilot then exhausts the loading pressure from the main valve
diaphragm chamber. The pilot continuously exhausts gas when
the inlet pressure is above the set pressure. The inlet pressure
unbalance overcomes the main spring force and opens the
diaphragm and plug assembly.
As the inlet pressure drops below the set pressure, the pilot
control spring closes the pilot valve plug and the exhaust to
atmosphere stops. Force from the main spring, along with pilot
loading pressure, pushes the diaphragm and plug assembly
onto the knife-edged seat, producing tight shutoff.
Backpressure Regulator
As long as inlet pressure remains below setpoint, the
pilot control spring keeps the pilot valve plug closed. Inlet
pressure passes through the upper port around the upper
portion of the valve plug and then through the hollow passage
in that valve plug. Force from the main spring, in addition to
pilot loading pressure, provide downward loading pressure to
keep the main valve diaphragm and plug assembly tightly shut
off. When inlet pressure rises above the set pressure, pressure
on the pilot diaphragm overcomes the control spring to close
the upper port and stroke the valve plug to open the lower
port. The pilot exhausts loading pressure from the main valve
diaphragm chamber. Inlet pressure unbalance overcomes the
main spring force to open the diaphragm and plug assembly.
While the main valve is throttling, the upper port of the pilot
stays closed. The pilot exhausts only when it repositions the
main valve. As inlet pressure drops below setpoint, the pilot
control spring overcomes the diaphragm force to stroke the
valve plug down to close the lower port and open the upper
port. Force from the main spring, along with pilot loading
pressure, pushes the diaphragm and plug assembly onto the
knife-edged seat, producing tight shutoff.
3
Type EZH Relief or Backpressure Regulator
Type EZH
Type EZH Single-Pilot Relief Valve or
Backpressure Regulator
Type EZH 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.
CAUTION
Personal injury or equipment damage, due
to bursting of pressure-containing parts may
result if this relief valve or backpressure
regulator is overpressured or is installed
where service conditions could exceed the
product and pilot pressure ratings.
CAUTION
When installing Type EZH trim in an existing
Fisher® E-body, damage can result if ow is not
in the correct direction. Look at the body web
to conrm that ow is in the correct direction—
up through the center of the cage and down
through the cage slots. Change the existing
ow arrow if necessary.
After assembly, check for shutoff and leakage
to atmosphere.
2. A Type EZH relief valve or backpressure regulator may
be installed in any orientation, as long as ow through it
matches the direction of the arrow on the main valve body.
3. Apply pipe compound to the external pipeline threads
before installing a relief valve or backpressure regulator
with threaded NPT end connections. Use gaskets between
pipeline and relief valve or backpressure regulator anges
when installing a relief valve or backpressure regulator
with anged end connections. When installing butt weld
end connections, remove trim before welding and make
sure to use approved welding practices. Use approved
piping procedures when installing the relief valve or
backpressure regulator.
Installation
WARNING
!
Personal injury, equipment damage, or
leakage due to escaping gas or bursting of
pressure-containing parts may result if the
Type EZH is installed where its capabilities
can be exceeded or where conditions
exceed any ratings of the adjacent piping or
connections. To avoid this, install a Type EZH
relief valve or backpressure regulator where:
• Service conditions are within unit
capabilities (including those in the
Specications section).
• Service conditions are within applicable
codes, regulations, or standards.
Additionally, physical damage to the relief
valve or backpressure regulator could break
the pilot off the main valve, causing personal
injury and property damage due to escaping
gas. To avoid such injury or damage, install
the unit in a safe location.
1. Only personnel qualied through training and
experience should install, operate, and maintain a relief
valve or backpressure regulator. Before installation,
make sure that there is no damage to, or debris in
the main valve body or pilot. Also, make sure that all
tubing and piping are clean and unobstructed.
WARNING
!
When used in relief valve service, the Type EZH
main valve and pilot both exhaust gas. In
hazardous or ammable gas service, personal
injury, death, or property damage may occur
due to re or explosion of vented gas that
has accumulated. To prevent such injury or
damage, provide piping or tubing to vent the
gas to a safe location. The exhaust piping
must be designed and installed to guard
against excessive ow restriction. This piping
must be protected against condensation or
debris that could clog it.
For safety during shutdown, vent valves
are required immediately upstream
and downstream of the main valve on a
backpressure or bypass installation.
4. If system operation during maintenance is required, install
isolating and vent valves as needed.
5. For the Type PRX/182 pilot, if the vent assembly (key 12,
Figure 7) remains in the pilot body (key 1, Figure 7), then
it must be pointed down if possible or otherwise protected.
If the exhaust is to be piped to the main valve exhaust or
remotely vented, remove the vent assembly and install
tubing or piping into the 1/4 NPT pilot exhaust connection.
Protect the open end of the exhaust pipe by installing a
screened vent cap.
4
Type EZH Relief or Backpressure Regulator
6. The Type PRX/182 pilot spring case vent (key 12,
Figure 7) must be kept open to atmospheric pressure.
Protect the vent assembly from icing, moisture, or debris
that may cause blockage, as required. To change the
vent orientation, twist the vent assembly in the spring
case. To remotely vent the pilot spring case, remove the
vent assembly and install tubing or piping into the 1/4 NPT
spring case vent tapping. Protect the open end of the vent
line by installing a screened vent cap.
7. The Type PRX pilot connections are 1/4 NPT. Connect
the inlet control (sense) line from the “A” port, Figure 6
(key 47) on the bottom of the PRX Series pilot to a straight
run of pipe 6 to 10 pipe diameters from the relief valve or
backpressure regulator inlet as shown in Figure 3 using
3/8-inch / 9.5 mm or larger outside diameter tubing. If such
a distance is not practical, connect the control line away
from elbows, swages, nipples, or any area where abnormal
ow velocities occur.
Startup and Shutdown
CAUTION
If pressure is introduced rst to the main
valve before the pilot, the main valve may
go wide-open and subject the downstream
system to full inlet pressure.
Shutdown
1. Close upstream block valve rst and then close the
downstream block valve.
2. Open downstream and upstream vent valves
(not shown).
Type PRX/182 Pilot Adjustment
For PRX Series pilots (Figure 7), loosen locknut
(key 2) and turn the adjusting screw into the spring case
to increase (or out of the spring case to decrease) the
downstream pressure. When the required downstream
pressure is maintained for several minutes, 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 uid. 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
Note
The maximum inlet pressure for specic
constructions are given in Table 6. Use a
pressure gauge to monitor inlet pressure
during startup.
Relief Installation (Figure 6)
Startup
1. Close vent valve (not shown).
2. Slowly open block valve and hand valve, if installed.
3. Adjust the pilot as needed.
Shutdown
1. Close block valve and hand valve, if installed.
2. Slowly open vent valve (not shown).
Backpressure Installation
Startup
1. Close upstream and downstream vent valves
(not shown).
2. Slowly open upstream block valve rst and then slowly
open downstream block valve.
3. Adjust the pilot as needed. If the pilot is not piped
downstream, make sure the pilot exhaust is pointed in
the correct direction.
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 pounds / 45 kg.
Customer cannot use another type of eyebolt
in the regulator. Only Regulator Technologies
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 Fisher® takes in
meeting all manufacturing requirements (heat treating,
dimensional tolerances, etc.), use only replacement parts
manufactured or furnished by Fisher. 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.
5
Type EZH Relief or Backpressure Regulator
Table 3. Torque Specications
TORQUE SPECIFICATIONS
PART NAME
Indicator Fitting or Plug (key 141) 10 to 30 14 to 41 10 to 30 14 to 41 10 to 30 14 to 41 10 to 30 14 to 41
Stud Nuts (key 26) 45 to 50 61 to 68 45 to 50 61 to 68 80 to 95 108 to 129 - - - -
Socket Head Cap Screws (key 16) 50 to 70
Stud Bolts (key 24) 50 to 70 68 to 95 50 to 70 68 to 75 100 to 120 136 to 163 - - - -
Cap Screws (key 21) 50 to 55 68 to 75 130 to 150 176 to 203 250 to 270 339 to 366 280 to 310 380 to 420
Cap Screws (key 6) 50 to 60 68 to 81 50 to 60 68 to 81 70 to 95 95 to 129 140 to 155 190 to 210
Socket Head Cap Screws (key 33) 30 to 40
Smart Screws (key 68) - - - - - - - - - - - - 31 to 40
Socket Head Cap Screws (key 74) - - - - - - - - - - - - 26 to 35
Cap Screws (key 77) - - - - - - - - - - - - 90 to 110 122 to 149
Sleeve Guide (key 61) - - - - - - - - - - - - 130 to 140 176 to 190
Cap Screw (key 154) 16
Stem Nut (key 151) 32 43 32 43 45
Stem Nut (key 155) 30
Hex Nut (key 152) - - - - 40
1. Torque specications are given in inch-pounds.
NPS 1 / DN 25 NPS 2 / DN 50 NPS 3 / DN 80 NPS 4 / DN 100
foot-pound N•m foot-pound N•m foot-pound N•m foot-pound N•m
(1)
5.6 to 7.9 50 to 70
(1)
3.4 to 4.5 50 to 60
(1)
1.8 50
41 - - - - - - - - - - - -
(1)
6 to 7.9 50 to 70
(1)
5.6 to 6.8 80 to 100
(1)
Body Size
(1)
6.2 to 7.9 100 to 115
(1)
9 to 11 80 to 100
5.6 10
54 60 81 45 to 50 61 to 68
14 2.9 to 3.5 3.9 to 4.7
61 45 to 50 61 to 68
(1)
11 to 13
(1)
9 to 11
(1)
3.5 to 4.5
(1)
2.9 to 4
Main Valve and Actuator Maintenance
NPS 1 through 3 / DN 25 through 80
Disk Maintenance (Refer to Figure 4)
For Type EZH:
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. See Torque Specications
(Table 3) for proper torque values.
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). See Torque Specications (Table 3) for
proper torque values.
NPS 4 / DN 100 Disk Maintenance
(Refer to Figure 4)
1. Remove cap screws (key 77).
2. Carefully lift the cap (key 70) off the upper actuator
casing (key 11) and unscrew the eye bolts (key 35) from
the cap (key 70).
3. Remove O-ring (key 75). Inspect the O-ring for damage
or wear, and replace if necessary.
4. Remove the O-ring (key 69). Inspect the O-ring for
damage or wear, and replace if necessary. Lubricate
O-ring before placing inside the cap (key 70).
5. Remove special screws (key 68) from sleeve (key 14).
6. Fit eye bolt (key 35) into the upper spring seat (key 73)
threaded hole.
7. Carefully remove the trim system from the sleeve guide
(key 61) using the eye bolts (key 35).
8. Remove socket head cap screws (key 33) and lock
washers (key 32).
9. Lift off the disk retainer (key 31) and disk holder assembly
(key 30).
10. Remove the O-ring (key 29). Inspect the O-ring for
damage or wear, replace if necessary. Lightly lubricate
O-ring before placing the sleeve adaptor (key 27).
11. Place disk holder assembly (key 30) onto disk retainer
(key 31).
6
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