Emerson FISHER 66R User manual

Types 66R and 66RR
Instruction Manual
D100248X012
February 2020
W1935
W1908
Types 66R and 66RR Relief Valves
TYPE 66R RELIEF VALVE TYPE 66RR RELIEF VALVE
Figure 1. Typical Constructions
Introduction
Scope of the Manual
This manual describes and provides instructions, installation,
and parts list for Type 66R direct-operated relief valve* and
for Type 66RR pilot-operated relief valve* complete with
Type T208RR pilot. Instructions and parts list for other
Fisher™ equipment used with these relief valves are found
in separate manuals.
Product Description
Types 66R and 66RR throttling relief valves (Figure 1) are
used to help protect a system against overpressure, or to
maintain an inlet or backpressure. The Type 66R direct-
operated construction is used for set pressure ranges of
2 in. w.c. to 5 psig / 5 mbar to 0.34 bar, while the Type 66RR
pilot-operated construction with the Type T208RR pilot is used
for set pressure ranges of 4 in. w.c. to 7 psig / 10 mbar to
0.48 bar.
Principle of Operation
Type 66R Relief Valve
Refer to Figure 2. Inlet pressure registers under the diaphragm
and is opposed by the spring. When the inlet pressure
increases above the spring setting, the valve plug opens in
a throttling manner and relieves the inlet pressure. As inlet
pressure drops back to set pressure, the spring closes the
valve plug.
Type 66RR Relief Valve
Refer to Figure 2. Inlet pressure registers on the bottom
of the pilot diaphragm through the upstream control line
and bleeds through a fixed restriction in the pilot to provide
loading pressure that helps the main valve spring keep the
main valve plug tightly shut off. When inlet pressure exceeds
the setting of the pilot spring, the pilot diaphragm moves
upward, opening the pilot valve disk and relieving some of
the pressure from the top of the main valve diaphragm. At
the same time, the inlet pressure increase registers on the
bottom of the main valve diaphragm.
*Relief valve dened in ANSI standard B95.1-1972. Not all codes or regulations permit these valves to be used as nal overpressure protection devices.

Types 66R and 66RR
2
!
The pressure di󰀨erential acting on the main valve diaphragm
moves this diaphragm upward, opening the main valve.
Further increases in inlet pressure continue to open the pilot
valve disk and the main valve plug. When inlet pressure
returns to the pilot control spring setting, the pilot disk
closes, allowing inlet pressure to load the top of the main
valve diaphragm through the xed restriction. This equalizes
the pressures acting on this diaphragm, and the main valve
spring closes the main valve plug.
Installation
Installing Types 66R and 66RR relief valve
where its capabilities can be exceeded may
cause leakage, part damage, or personal
injury due to bursting of pressure-containing
parts or explosion of accumulated gas. To
avoid this, install a Type 66R or 66RR relief
valve where:
• Service conditions are within unit
capabilities (including those given in the
Specications section),
• Service conditions are within applicable
local, state, or federal codes or
regulations, and
• The unit is protected from exposure
to physical damage and/or
corrosive substances.
1. Use qualified personnel when installing, operating, and
maintaining these relief valves. Before installing, inspect
the relief valve, and pilot if used, for any damage or
foreign material that may have collected.
2. Make certain the body interior is clean and that
pipelines are free of foreign material. Apply pipe
compound to only the male pipeline threads with an
NPT body, or use suitable line gaskets and acceptable
bolting practices with a flanged body.
Specifications
Refer to Specifications for Types 66R and 66RR constructions listed on page 2. Some specifications for a given relief valve as
it originally comes from the factory are stamped on nameplates located on the Type 66R relief valve body or Type 66RR main
valve body.
Body Sizes and End Connection Styles
Maximum Relief Inlet Pressure(1)
Type 66R: 8 psig / 0.55 bar, including build-up
Type 66RR: 10 psig / 0.69 bar, including build-up
Relief Set Pressure Ranges(1)
Type 66R: 2 in. w.c. to 5 psig / 5 mbar to 0.34 bar in
7 ranges
Type 66RR: 4 in. w.c. to 7 psig / 10 mbar to 0.48 bar
See Table 1
Allowable Emergency Outlet Pressure
Type 66R: 8 psig / 0.55 bar
Type 66RR: 10 psig / 0.69 bar
Port Diameters
NPS 2 / DN 50 Body: 2 in. / 51 mm
NPS 3 / DN 80 Body: 3 in. / 76 mm
NPS 4 / DN 100 Body: 4 in. / 102 mm
Temperature Capabilities
Standard Elastomers: -20 to 180°F / -29 to 82°C
High-Temperature Elastomers: 0 to 350°F /
-18 to 177°C
Pressure Setting Adjustment
Adjusting screw
Pressure Registration
Type 66R: Internal (standard) or external
Type 66RR: External on pilot and internal in main valve
Pressure Connections
Type 66R
Control Line (if used): 3/4 NPT internal
Spring Case Vent: 3/4 NPT internal with removable
Type Y602-10 vent assembly
Type 66RR
Pilot Body: 3/4 NPT internal
Pilot Diaphragm Case: 1/2 NPT internal
Pilot Spring Case: 1/4 NPT internal
Approximate Weights
NPS 2 (DN 50) Body
NPT: 50 lbs / 23 kg for Type 66R or 65 pounds / 30 kg
for Type 66RR
Flanged: 55 pounds / 25 kg for Type 66R or 70 lbs /
32 kg for Type 66RR
NPS 3 (DN 80) Body: 100 pounds / 45 kg for Type 66R
or 115 lbs / 52 kg for Type 66RR
NPS 4 (DN 100) Body: 155 lbs / 70 kg for Type 66R or
170 lbs / 77 kg for Type 66RR
NOMINAL SIZE,
NPS / DN
END CONNECTION STYLES AND RATINGS(1)
Standard Cast Iron Body Optional Steel Body
2 / 50 NPT or CL125 FF
Flanged
NPT, CL150 RF, and
CL300 RF Flanged
3, 4 /
80, 100 CL125 FF Flanged CL150 RF Flanged
1. The pressure/temperature limits in this Instruction Manual and any applicable standard or code limitation should not be exceeded.
WARNING

Types 66R and 66RR
3
M1041
!
3. Install a Type 66R or 66RR relief valve in a horizontal
pipeline with the diaphragm casings above the body.
Other orientations will change the relief set pressure
and set pressure range due to the weight of the internal
parts. The flow through the relief valve must comply with
the flow arrow on the body.
4. An upstream control line is not required for a standard
Type 66R relief valve with internal registration through
a stem guide (key 41, Figure 6). However, for an
optional Type 66R relief valve with sealing diaphragm
(key 14, Figure 6), connect a control line to the 3/4 NPT
tapped connection boss on the diaphragm case (key 3,
Figure 6) as shown in Figure 3.
5. For a Type 66RR relief valve used in a relief application,
connect an upstream control line to the 1/2 NPT
connection on the pilot diaphragm case (key 4, Figure 8).
For other typical applications, piping arrangements are
shown in Figures 4 and 5. Regardless of Type 66RR
installation, the pipe plug (key 78, not shown) will have
to be removed from the vent of the Type T208RR pilot
spring case (key 3, Figure 8).
6. On backpressure or bypass applications, install a three-
valve isolating bypass, and vent valves immediately
upstream and downstream of the unit, if system
operation is necessary during maintenance.
Relief valves vent gas from the main valve
outlet and from the exhaust of the pilot if
used. In hazardous gas service, personal
injury and equipment damage may occur
due to re or explosion of vented gas that
has accumulated. To prevent such injury and
damage, provide piping or tubing to vent
the gas to a safe location. Protect the vent
opening against anything that could clog it.
7. The standard Type 66R spring case (key 2, Figure 6)
has a Type Y602-10 vent assembly (key 30, Figure 6)
installed in the 3/4 NPT spring case tapping. The vent
may be removed and obstruction-free piping or tubing
installed for remote piping of the spring case or for
pressure loading of the spring case as shown in Figure 5.
If kept in the spring case, the vent must be protected
against clogging.
PILOT
CONTROL
SPRING
DIAPHRAGM
VALVE
PLUG SKIRT
FIXED
RESTRICTION
PILOT
VALVE DISK
MAIN VALVE
DIAPHRAGM
TYPE T208RR
PILOT
VALVE STEM
VALVE PLUG
SKIRT
MAIN VALVE
TYPE 66RRTYPE 66R
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
LOADING PRESSURE
Figure 2. Operational Schematics
Table 1. Type T208RR Pilot Control Spring Selection
MAIN VALVE
CONSTRUCTION RELIEF SET PRESSURE RANGE
PILOT CONTROL SPRING
Part Number Color Code Wire Diameter,
In. / mm
Free Length,
In. / mm
Standard
4 to 9 in. w.c. / 10 to 22 mbar(1)
5 to 15 in. w.c. / 12 to 37 mbar(1)
12 to 28 in. w.c. / 30 to 70 mbar(1)
0.9 to 2.5 psig / 0.06 to 0.17 bar
1.3 to 4.5 psig / 0.09 to 0.31 bar
1B653827052
1B653927022
1B537027052
1B537127022
1B537227022
Red
Olive drab
Yellow
Light green
Light blue
0.085 / 2.16
0.105 / 2.67
0.114 / 2.90
0.156 / 3.96
0.187 / 4.75
3.625 / 92.1
3.750 / 95.3
4.188 / 106
4.060 / 103
3.938 / 100
Special 3.8 to 7 psig / 0.26 to 0.48 bar 1B537327052 Black 0.218 / 5.54 3.980 / 101
1. Published ranges are with the spring case pointed up.
WARNING

Types 66R and 66RR
4
BJ8921-C
A2562
AV9712-D
A2564
AV9712-D
A2563-1
8. Each unit is factory-set for the set pressure specified
on the order. If no setting is specified, set pressure is
factory set at the mid-range of the Type 66R spring
(key 6, Figure 6) or the Type 66RR pilot control spring
(key 6, Figure 8). The set pressure of a unit is adjusted
by changing the compression of the appropriate spring.
Check and verify the spring setting to make sure that it is
correct for the application.
9. Set pressure for a Type 66RR relief valve is defined
as the pressure at which the main valve starts-to-
discharge. Type 66RR units have been designed so that
either a 1 in. w.c. / 2.50 mbar build-up or a 5 percent
build-up (whichever is greater) above this set pressure
will open the main valve and permit it to yield full
open capacity.
Startup
Key numbers are referenced in Figure 6 for the Type 66R
relief valve, in Figure 7 for the Type 66RR main valve, and in
Figure 8 for the Type 66RR relief valve pilot.
With proper installation and adjustment completed, slowly
open the upstream shutoff valve while using gauges to
monitor pressure. To monitor inlet pressure, remove the pipe
plug (key 31, not shown) on the side of the body opposite
the flow arrow, and then temporarily install a gauge.
On backpressure or bypass applications using an isolating
bypass, also open the downstream shutoff valve and close
the bypass valve.
If set pressure adjustment is necessary, monitor inlet
pressure with a gauge during the adjustment procedure.
Adjust a Type 66R relief valve by removing the closing
cap (key 27) if necessary, loosening the locknut (key 45) if
used, and turning the adjusting screw (key 25) clockwise to
increase or counterclockwise to decrease the set pressure.
After adjustment, tighten the locknut or install the closing
cap. To adjust a Type 66RR relief, remove the Type T208RR
pilot closing cap (key 22), turn the adjusting screw (key 35)
clockwise to increase or counterclockwise to decrease the
set pressure, and then install the closing cap.
Shutdown
Relief Installations
Slowly close the upstream shutoff valve. Release all
pressure from the relief valve, and pilot if used, by opening
the upstream vent valve.
Backpressure or Bypass Installations
Slowly close the upstream shutoff valve, while opening the
bypass valve if an isolating bypass is used. Then, close the
downstream shutoff valve, and open both vent valves to
release all pressure from the relief valve (and pilot if used).
CONTROL LINE
GAS TO
FUEL
SYSTEM
COMPRESSOR
DIGESTER
TANK
CONTROL LINE
ATMOSPHERE
ONLY INTO
DIAPHRAGM CASE
VENT
VACUUM
BEING
LIMITED
VACUUM PUMP
POSITIVE PRESSURE
OR ATMOSPHERE, OR A
LESSER VACUUM THAN THE
VACUUM BEING LIMITED
ATMOSPHERE ONLY INTO
SPRING CASE VENT
SPECIAL
PILOT
CONSTRUCTION
VACUUM
BEING
REGULATED
UNAVOIDABLE
LEAKAGE
HIGHER
VACUUM
SOURCE
VACUUM
PUMP
Figure 3. Type 66R Relief Valve Installation at
Outlet of Sewage Treatment Plant Digester Tank
Figure 4. Type 66RR Relief Valve Installation
in Vacuum Breaker System
Figure 5. Type 66R Relief Valve Installation in
Vacuum Regulation System

Types 66R and 66RR
5
!
Maintenance
Relief valve parts are subject to normal wear and must
be inspected and replaced as necessary. The frequency
of inspection and replacement of parts depends upon the
severity of service conditions and the requirements of local,
state, and federal regulations.
Avoid personal injury or property damage
from sudden release of pressure or
explosion of accumulated gas. Before
starting to disassemble:
• Isolate the relief valve from line pressure,
• Release trapped pressure from the body, and
• Vent any trapped loading pressure.
Type 66R Relief Valve or Type 66RR Main
Valve Body
This section gives procedures for complete disassembly and
assembly of the relief valve or main valve body. Disassemble
the valve only as far as required to gain access to the
necessary parts. Then, begin the “Assembly” procedure at
the appropriate step. Key numbers for the Type 66R relief
valve are referenced in Figure 6 and, for the Type 66RR
main valve, in Figure 7.
Note
All disassembly and assembly steps in this
section may be performed with the relief
valve in the main line. If used, the pilot and
its mounting parts (keys 60 through 65, and
67, Figure 7) may remain on the spring case
(key 2) unless the pilot body is to be removed
or the entire pilot replaced as a unit.
Disassembly
1. With a Type 66RR relief valve, disconnect the pilot
control and/or vent lines.
2. Loosen the locknut (key 45) if used, and remove the
closing cap (key 27) and closing cap gasket (key 26).
3. In order to facilitate resetting spring compression
during assembly, be sure to note the position of the
adjusting screw (key 25) before removing it. Then, turn
the screw out of the spring case (key 2) to remove
spring compression, and remove the upper spring seat
(key 24), spring (key 6), cap screws and nuts (keys 21
and 22), and spring case.
4. Unscrew the stem nut (key 23) from the top of the stem
(key 13). To keep the stem from twisting, lift the diaphragm
(key 5) and attached parts far enough to hold the stem with
an open-end wrench. Or, remove the pipe plug (key 31, not
shown) from the side of the body opposite the arrow, and
insert a 5/16 in. / 7.94 mm or smaller rod through the pipe
plug hole and the hole in the stem.
5. Remove the spring seat washer (key 36) if used, lower
spring seat (key 17), stiffener plate (key 39) if used,
upper diaphragm plate (key 4), diaphragm (key 5),
lower diaphragm plate (key 15), stem gasket (key 18),
diaphragm spacer (key 16) if used, and another stem
gasket and lower diaphragm plate if used. With a high-
temperature Fluorocarbon (FKM) diaphragm, remove
the diaphragm gasket (key 66, not shown) that goes
between the diaphragm and diaphragm case (key 3).
6. Remove the cap screws (key 20) and washers (key 34)
that attach the diaphragm case to the body (key 1).
7. Remove the diaphragm case and diaphragm case gasket
(key 35). Depending on construction, remove either the
stem guide (key 41) or the sealing diaphragm (key 14)
and last lower diaphragm plate (key 15) and stem gasket
(key 18). If used, remove the rod from the stem and the
pipe plug hole in the body.
8. Lift out the stem and attached parts.
9. Unscrew the stem nut (key 23) from the bottom of the
stem, and remove the valve plug skirt (key 10), O-ring
(key 8), O-ring retainer (key 9), and seal washer (key 37).
10. Slide a seat ring puller, T-wrench, or other suitable tool
over the seat ring (key 11). Engage the tool with the seat
ring lugs. Unscrew the seat ring.
11. If necessary to replace the bottom flange gasket
(key 19), remove the cap screws (key 20), bottom flange
(key 7), and gasket.
Assembly
1. Apply pipe compound to the threads of the seat ring
(key 11). Screw in the seat ring, using a seat ring puller
or similar device. Wipe off any excess pipe compound.
2. Place the seal washer (key 37), O-ring retainer (key 9),
O-ring (key 8), and valve plug skirt (key 10) on the stem
(key 13) in the order shown in Figure 6 or 7.
3. Secure the stem nut (key 23) to the stem. Install the
stem and attached parts into the body.
4. If necessary, install a new bottom flange gasket (key 19)
and the bottom flange (key 7) on the valve body. Secure
the flange with the cap screws (key 20).
5. Depending on construction, either install the stem guide
(key 41) on the body, or install the stem gasket (key 18),
lower diaphragm plate (key 15), and the sealing
diaphragm (key 14) on the stem. Make sure that on a
sealing diaphragm, the diaphragm holes are aligned
with the body flange holes.
6. Install the diaphragm case gasket (key 35) and
diaphragm case (key 3) on either the body flange or
sealing diaphragm, making sure the gasket and case
holes are aligned with the body flange holes.
WARNING

Types 66R and 66RR
6
!
WARNING
7. Secure the diaphragm case with the washers (key 34)
and cap screws (key 20), tightening the cap screws with
an even crisscross pattern. With a high-temperature
Fluorocarbon (FKM) diaphragm, use a new case
gasket (key 66, not shown), and install it on top of the
diaphragm case.
8. With a sealing diaphragm construction, place another
lower diaphragm plate on the sealing diaphragm so
that the cupped side of the plate faces up, followed by
another stem gasket (key 18) and the diaphragm spacer
(key 16) if used.
9. Place a stem gasket (key 18) on the stem or diaphragm
spacer, followed by the lower diaphragm plate (key 15),
diaphragm (key 5), upper diaphragm plate (key 4),
stiffener plate (key 39) if used, lower spring seat
(key 17), and spring seat washer (key 36) if used.
10. To keep the stem (key 13) from rotating, insert a
5/16 in. / 7.9 mm or smaller rod into the pipe plug hole
and through the hole in the stem, or reach far enough
under the diaphragm with an open-end wrench to hold
the stem. Install the other stem nut (key 23) on the stem.
11. Remove the rod (if used) from the pipe plug hole, and
install the pipe plug (key 31, not shown) in the body.
When changing from one spring to another, a
new spring case with set screw in a di󰀨erent
location must be matched to the replacement
spring. Installing an incorrect spring case
when changing from one spring to another
may cause the spring to go solid and restrict
the full opening of the valve plug. This
could keep the relief valve from full-capacity
performance and thus cause personal injury
or equipment damage. To avoid this, order
a replacement spring case according to the
“Parts List”.
12. Install the spring case (key 2) on the diaphragm, and
secure with the cap screws and nuts (keys 21 and 22),
finger-tightening only at this point.
13. Install the spring (key 6), upper spring seat (key 24),
adjusting screw (key 25), and new closing cap gasket
(key 26). With some constructions, the closing
cap (key 27) will have to be installed before the
adjusting screw.
14. Compress the spring slightly with the adjusting screw to
ensure proper slack in the diaphragm. Tighten the nuts
and cap screws alternately in equal increments to avoid
crushing the diaphragm.
15. Turn a Type 66RR adjusting screw into the spring case to
the position noted in “Disassembly” step 3. If this position
was not marked, turn the adjusting screw until the
valve begins to open when inlet pressure just exceeds
2 in. w.c. / 5 mbar.
16. Complete the relief valve adjustment according to the
“Startup” section.
Type 66RR Relief Valve Pilot
Body Area
This procedure is for gaining access to the disk assembly,
orifice, and body seal O-ring. All pressure must be released
from the regulator, before the following steps can be
performed. Key numbers are referenced in Figure 8.
1. To inspect and replace the disk assembly (key 13)
remove the body cap assembly (key 43).
2. Remove the disk assembly (key 13) from the disk
spacer (key 44) and replace if necessary.
3. To inspect the orifice (key 5), remove the cap screws
(key 2) and separate the diaphragm case assembly
(key 4) from the body (key 1).
4. Remove and inspect the body seal O-ring (key 11) and
the backup ring (key 49). Replace if damaged.
5. Inspect and replace the orifice (key 5) if necessary.
Lightly lubricate the threads of the replacement
orifice. Install with 340 to 470 in-lbs / 38.5 to 53.1 N•m
of torque.
6. Install the backup ring (key 49) into the body (key 1).
Next place the body seal O-ring (key 11) into the body.
See Figure 8.
7. Replace the diaphragm casing (key 4) on the body
(key 1) and secure with the cap screws (key 2) using
90 to 126 in-lbs / 10.2 to 14.2 N•m of torque.
8. Secure the disk assembly (key 13) to the disk spacer
(key 44). Place the back disk spring (key 41) and a new
back body seal O-ring (key 42) on the back body cap
(key 43).
9. Lightly lubricate the threads when replacing the body
cap assembly. Use 340 to 470 in-lbs / 38.5 to 53.1 N•m
of torque.
Diaphragm and Spring Case Area
This procedure is for gaining access to the control spring,
diaphragm, and lever assembly stem. All pressure must
be released from the diaphragm case assembly before
performing the following steps. Key numbers are referenced
in Figure 8.
To Change the Control Spring
For internal flat circular adjusting screw
1. Remove the closing cap (key 22) and closing cap
gasket (key 25). Turn the adjusting screw (key 35)
counterclockwise to remove all the compression from
the control spring (key 6).

Types 66R and 66RR
7
2. Remove the adjusting screw (key 35) and change the
control spring (key 6) to match the desired spring range.
3. Install the adjusting screw (key 35).
4. Adjust the outlet pressure to the desired control
pressure setting, refer to steps 2 and 3 of
Adjustment section.
5. Change the stamped spring range on the spring
case nameplate.
For external square head adjusting screw
1. Loosen the locknut (key 20) and turn the adjusting
screw (key 35) counterclockwise to remove all the
compression from the control spring (key 6).
2. Remove the adjusting screw (key 35), locknut (key 20),
closing cap (key 22), closing cap gasket (key 25) and
upper spring seat (key 19).
3. Take out the control spring (key 6) and replace with the
desired spring.
4. Reinstall the upper spring seat (key 19), closing cap
gasket (key 25), closing cap (key 22), locknut (key 20)
and adjusting screw (key 35).
5. Adjust the outlet pressure to the desired control
pressure setting, refer to steps 2 and 3 of
Adjustment section.
6. Change the stamped spring range on the nameplate.
To Disassemble and Reassemble
Diaphragm Parts
Use this procedure to gain access to the control spring,
diaphragm assembly, valve stem and stem O-ring. All
pressure must be released from the diaphragm case
assembly before performing these steps. Key numbers are
referenced in Figure 8.
1. For internal flat circular adjusting screw - remove the
closing cap (key 22), closing cap gasket (key 25) and
adjusting screw (key 35).
For external square head adjusting screw - remove
the adjusting screw (key 35), locknut (key 20), closing
cap (key 22), closing cap gasket (key 25) and upper
spring seat (key 19).
2. Remove the hex nuts (key 23) and cap screws (key 24).
Lift off the spring case (key 3) and remove the control
spring (key 6).
3. Remove the diaphragm (key 10) plus attached parts by
tilting them so that the pusher post (key 8) slips off the
lever assembly (key 16). To separate the diaphragm
assembly from the attached parts, unscrew the cap
screw (key 38) from the pusher post. If the only
maintenance is to replace the diaphragm components,
skip to step 7.
4. To replace the lever assembly (key 16), remove the
machine screws (key 17). To replace the stem (key 14)
or stem seal O-ring (key 30), also perform Body Area
Maintenance procedure steps 1 through 3 and pull the
stem (key 14) out of the guide insert (key 18).
5. Install the stem (key 14) into the guide insert (key 18)
and perform Body Area Maintenance procedure steps
7 through 10 as necessary.
6. Install the lever assembly (key 16) into the stem (key 14)
and secure the lever assembly with the machine screws
(key 17).
7. Reassemble the diaphragm parts as follows:
• Pusher post (key 8)
• Diaphragm head gasket (key 45)
• Diaphragm head (key 7)
• Diaphragm (key 10)
• Diaphragm head
• Lower spring seat (key 50)
• Washer (key 36)
Secure the parts with diaphragm plate cap screw
(key 38) using 60 to 72 in-lbs / 6.8 to 8.1 N•m of torque.
8. Install the pusher post (key 8) and attached diaphragm
parts onto the lever assembly (key 16).
9. Install the spring case (key 3) on the lower casing
(key 4) so that the vent assembly (key 26) is correctly
oriented and secure them with the cap screws (key 24)
and hex nuts (key 23) to finger tightness only.
10. Install the parts into the spring case (key 3).
Follow the order below:
For internal flat circular adjusting screw
a. Control spring (key 6)
b. Adjusting screw (key 35)
For external square head adjusting screw
a. Control spring (key 6)
b. Upper spring seat (key 19)
c. Closing cap gasket (key 25)
d. Closing cap (key 22)
e. Locknut (key 20)
f. Adjusting screw (key 35)
11. Turn the adjusting screw (key 35) clockwise until there
is enough control spring (key 6) force to provide proper
slack to diaphragm (key 10). Using a crisscross pattern,
finish tightening the cap screws (key 24) and hex nuts
(key 23) to 98 to 126 in-lbs / 11.1 to 14.2 N•m of torque.
Adjust the control pressure to the desired pressure
setting, refer to the Adjustment section.
Parts Ordering
A Type 66R or 66RR relief valve has a serial number
stamped on a nameplate attached to the diaphragm case.
When corresponding with your local Sales Office, always
refer to this serial number. Also, when ordering replacement
parts, give the complete 11-character part number of each
needed part as found in the following parts list.

Types 66R and 66RR
8
Parts List
Type 66R Relief Valve (Figure 6) or
Type 66RR Main Valve Body (Figure 7)
Key Description Part Number
1 Body
Cast iron (not for use with sealing diaphragm)
2 NPT 2K556819012
CL125 FF anged
NPS 2 / DN 50 2K557019012
NPS 3 / DN 80 2K557219012
NPS 4 / DN 100 2K557419012
Cast iron for use with sealing diaphragm
(Type 66R only)
2 NPT 2K556719012
CL125 FF anged
NPS 2 / DN 50 2K5569X0012
NPS 3 / DN 80 2K557119012
NPS 4 / DN 100 2K557319012
WCC Steel (not for use with sealing diaphragm)
2 NPT 2L3505X0012
CL150 RF anged
NPS 2 / DN 50 2J840122012
NPS 3 / DN 80 2P936022012
NPS 4 / DN 100 2N850022012
NPS 2 / DN 50 CL300 RF anged 2L4426X0012
2 Spring Case, Steel (complete with
Stainless steel drive screw) See following table
3 Diaphragm Case, Steel
Standard
NPS 2 / DN 50 body 3D478728992
NPS 3 / DN 80 body 3D478928992
NPS 4 / DN 100 body 3D479128992
Optional 3/4 NPT tapped
(for Type 66R with sealing diaphragm only)
NPS 2 / DN 50 body 1F4421000A2
NPS 3 / DN 80 body 1F4419000A2
NPS 4 / DN 100 body 1F1319000A2
4 Upper Diaphragm Plate, Zinc-plated steel
NPS 2 / DN 50 body
2 in. w.c. to 2 psig / 5 mbar to 0.14 bar
set pressures for Type 66R or 3 in. w.c.
to 3.25 psig / 7 mbar to 0.22 bar
set pressures for Type 66RR 1D255625072
1.5 to 5 psig / 0.10 to 0.34 bar
set pressures for Type 66R or 3.25 to
7 psig / 0.22 to 0.48 bar
set pressures for Type 66RR 1D555725012
NPS 3 / DN 80 body 1D477328992
NPS 4 / DN 100 body 1D477425062
5* Diaphragm
Nitrile (NBR)
NPS 2 / DN 50 body 1D477002072
NPS 3 / DN 80 body 1D477102072
NPS 4 / DN 100 body 1D477202072
Fluorocarbon (FKM)
NPS 2 / DN 50 body 1D477002332
NPS 3 / DN 80 body 1D477102332
NPS 4 / DN 100 body 1D477202332
6 Spring, Zinc-plated steel See following table
7 Bottom Flange, Steel
NPS 2 / DN 50 body 1D477825062
NPS 3 / DN 80 body 17A9250X012
NPS 4 / DN 100 body 1D478025062
Key Description Part Number
8* O-ring
Nitrile (NBR)
NPS 2 / DN 50 body 1D785306992
NPS 3 / DN 80 body 1D785406992
NPS 4 / DN 100 body 1D785506992
Fluorocarbon (FKM)
NPS 2 / DN 50 body 1N115606382
NPS 3 / DN 80 body 1N115706382
NPS 4 / DN 100 body 1D2658X0022
9 O-ring Retainer
Brass
NPS 2 / DN 50 body 1D475814012
NPS 3 / DN 80 body 1D475914012
NPS 4 / DN 100 body 1D476014012
316 Stainless steel
NPS 2 / DN 50 body 1D475835072
NPS 3 / DN 80 body 1D475935072
NPS 4 / DN 100 body 1D476035072
10 Valve Plug Skirt
Brass
NPS 2 / DN 50 body 1D476112012
NPS 3 / DN 80 body 1D476212012
NPS 4 / DN 100 body 1D476312012
316 Stainless steel
NPS 2 / DN 50 body 1D476133092
NPS 3 / DN 80 body 1D476233092
NPS 4 / DN 100 body 1D476333092
11 Seat Ring
Bronze
NPS 2 / DN 50 body 1D783012022
NPS 3 / DN 80 body 1D783112022
NPS 4 / DN 100 body 1D783212022
316 Stainless steel
NPS 2 / DN 50 body 1D783033092
NPS 3 / DN 80 body 1D783133092
NPS 4 / DN 100 body 1D783233092
13 Valve Stem
For use without sealing diaphragm
Brass
NPS 2 / DN 50 body 1D752914012
NPS 3 / DN 80 body
Cast iron body 1D754514012
Steel body 1N4455X0012
NPS 4 / DN 100 body 1D759614012
316 Stainless steel
NPS 2 / DN 50 body 1D752935072
NPS 3 / DN 80 body
Cast iron body 1D754535072
Steel body 1N445535072
NPS 4 / DN 100 body 1D759635072
For use with sealing diaphragm
Brass
NPS 2 / DN 50 body 1J820214012
NPS 3 / DN 80 body 1J259114012
NPS 4 / DN 100 body 1J130814012
For use with sealing diaphragm
316 Stainless steel
NPS 2 / DN 50 body 1J820235072
NPS 3 / DN 80 body 1J259135072
NPS 4 / DN 100 body 1J130835072
14* Sealing Diaphragm (for Type 66R
with tapped diaphragm case only)
Nitrile (NBR)
NPS 2 / DN 50 body 1H737002042
NPS 3 / DN 80 body 1J198102042
NPS 4 / DN 100 body 1H727502042
Fluorocarbon (FKM)
NPS 2 / DN 50 body 1H7370X0012
NPS 3 / DN 80 body 1J1981X0012
NPS 4 / DN 100 body 1H7275X0012
*Recommended spare part.

Types 66R and 66RR
9
Key Description Part Number
15 Lower Diaphragm Plate, Zinc-plated steel
(1 required without and 3 required with
sealing diaphragm)
NPS 2 / DN 50 body 1D475725062
NPS 3 / DN 80 body 1D479325062
NPS 4 / DN 100 body 1D479425062
16 Diaphragm Spacer (for Type 66R
with sealing diaphragm only),
Zinc-plated steel
NPS 2 / DN 50 body 1J820326092
NPS 3 / DN 80 body 1J259226092
NPS 4 / DN 100 body 1J130926092
17 Lower Spring Seat
Type 66R thru 3 psig / 0.21 bar
set pressures and all Type 66RR,
Aluminum 0X014744012
Type 66R for 3 to 5 psig /
0.21 to 0.34 bar set pressures,
Brass 1J331314012
18* Stem Gasket, Composition (1 required without
and 3 required with sealing diaphragm)
NPS 2 or 3 / DN 50 or 80 body 1D255304022
NPS 4 / DN 100 body 1D478404022
19* Bottom Flange Gasket, Composition
NPS 2 / DN 50 body 1D476404022
NPS 3 / DN 80 body 1D476504022
NPS 4 / DN 100 body 1D476604022
20 Cap Screw, Zinc-plated steel
NPS 2 / DN 50 body
Cast iron body (13 required) 1C631224052
Steel body (12 required) 1C275224052
NPS 3 / DN 80 body (17 required
for Cast iron or 16 for Steel body) 1D529824052
NPS 4 / DN 100 body (17 required
for Cast iron or 16 for Steel body) 1D530824052
21 Cap Screw, Zinc-plated steel
(16 required for NPS 2 / DN 50,
20 for NPS 3 / DN 80, or 24
for NPS 4 / DN 100 body) 1D529624052
22 Hex Nut, Zinc-plated steel
(16 required for NPS 2 / DN 50,
20 for NPS 3 / DN 80, or 24 for
NPS 4 / DN 100 body) 1A309324122
23 Stem Nut (2 required)
Brass
NPS 2 or 3 / DN 50 or 80 body 1D529718992
NPS 4 / DN 100 body 1D530918992
Stainless steel
NPS 2 or 3 / DN 50 or 80 body 1D5297X0022
NPS 4 / DN 100 body 1D5309X0052
24 Upper Spring Seat
Type 66R for 3 to 5 psig / 0.21 to
0.34 bar set pressures, Brass
NPS 2 or 3 / DN 50 or 80 body 1J331214012
NPS 4 / DN 100 body 1E271114012
25 Adjusting Screw
Type 66R thru 2 psig / 0.14 bar
set pressures and all Type 66RR, Aluminum 1L928608012
Type 66R for 1.5 to 3 psig / 0.10 to 0.21 bar
set pressures, Brass 1V9069X0012
Type 66R for 3 to 5 psig / 0.21 to 0.34 bar
set pressures (except NPS 4 / DN 100 body),
Zinc-plated steel
NPS 2 / DN 50 body 1A279128982
NPS 3 / DN 80 body 1N506624102
26* Closing Cap Gasket
Neoprene 1N446206992
Key Description Part Number
27 Closing Cap
Type 66R thru 3 psig / 0.21 bar
set pressures and all Type 66RR, Die-cast zinc 1A589544022
Type 66R for 3 to 5 psig / 0.21 to 0.34 bar
set pressures, Brass 1H798714012
28 Flapper Valve (for Type 66R only),
Brass 1C901715072
29 Snap Ring (for Type 66R only),
Bronze 1D178016012
30 Type Y602-10 Vent Assembly,
Stainless steel/Zinc/Monel®EMY602X1-A10
31 Pipe Plug (not shown)
Steel 1A369224492
34 Washer, Zinc-plated steel
NPS 2 / DN 50 body (7 required for
cast iron or 6 for steel body) 1D793624152
NPS 3 / DN 80 body (9 required for
cast iron or 8 for steel body) 1D716228982
NPS 4 / DN 100 body (9 required for
cast iron or 8 for steel body) 1D716328982
35* Diaphragm Case Gasket, Neoprene
Cast iron body
NPS 2 / DN 50 1D843604082
NPS 3 / DN 80 1D843704082
NPS 4 / DN 100 1D843804082
Steel body
NPS 2 / DN 50 1D753004082
NPS 3 / DN 80 1D754704082
NPS 4 / DN 100 1D843804082
36 Spring Seat Washer (for use only with
NPS 2 or 3 / DN 50 or 80 body),
Zinc-plated steel 1H723125072
37 Seal Washer
NPS 2 or 3 / DN 50 or 80 body, Steel 1F990428982
NPS 4 / DN 100 body, Brass 1H720799012
39 Sti󰀨ener Plate, Steel
2 in. w.c. to 2 psig / 5 mbar to 0.14 bar
set pressures for Type 66R or 3 in. w.c. to
3.25 psig / 7 mbar to 0.22 bar
set pressures for Type 66RR
NPS 2 or 3 / DN 50 or 80 body 1D753125062
NPS 4 / DN 100 body 1D760725072
1.5 to 5 psig / 0.10 to 0.34 bar
set pressures for Type 66R or 3.25 to 7 psig /
0.22 to 0.48 bar set pressures for Type 66RR
(not used with NPS 2 / DN 50 body)
NPS 3 / DN 80 body 1E204325012
NPS 4 / DN 100 body 1A355325012
40 Drive Screw, 18-8 Stainless steel 1A368228982
41 Stem Guide (not for use with sealing diaphragm)
Steel
NPS 2 / DN 50 body 1D752824092
NPS 3 / DN 80 body 1D754625032
NPS 4 / DN 100 body 1D759725032
Stainless steel
NPS 2 / DN 50 body 1D752835132
NPS 3 / DN 80 body 1D754635132
NPS 4 / DN 100 body 1D759735072
45 Locknut for 3 to 5 psig / 0.21 to 0.34 bar
set pressure Type 66R only,
Zinc-plated steel 1A352424122
60 U-Bolt (for Type 66RR only),
Steel 11A7488X012
61 U-Bolt (for Type 66RR only), Steel 11A7489X012
62 Mounting Bar (for Type 66RR only), Steel
NPS 2 / DN 50 body 11A7490X012
NPS 3 / DN 80 body 11A8938X012
NPS 4 / DN 100 body 11A8939X012
*Recommended spare part.
Monel® is a mark owned by Special Metals Corporation

Types 66R and 66RR
10
Type 66R Relief Valve (Figure 6) or
Type 66RR Main Valve Body (Figure 7)
(continued)
Key Description Part Number
63 Pipe Union (for Type 66RR only),
Malleable iron 1B540621992
64 Pipe Nipple (for Type 66RR only),
Steel 1K994226012
65 Hex Nut (for Type 66RR only),
Zinc-plated steel (4 required) 1A345724122
66* Diaphragm Gasket [for Fluorocarbon (FKM)
diaphragm only], Fluorocarbon (FKM) (not shown)
NPS 2 / DN 50 body 1U6985X0012
NPS 3 / DN 80 body 1U6986X0012
NPS 4 / DN 100 body 1U6989X0012
67 Pipe Nipple (for Type 66RR),
Steel 1B539126012
Type T208RR Pilot
Key Description Part Number
1 Body, Gray Cast Iron ERSA03695A0
2 Cap Screw (2 required), Zinc-plated steel 1C856228992
3 Spring Case, Gray cast iron ERSA02558A0
4 Lower Casing, Gray cast iron 47B2271X012
5 Orice, Stainless steel
7/16 in. / 11 mm 0L0832X0012
6 Spring See Table 1
7 Diaphragm Head (2 required), Stainless steel 17B9723X032
8 Pusher Post, Stainless steel 18B3462X012
10 Diaphragm
Nitrile (NBR) 17B9726X012
Fluorocarbon (FKM) 23B0101X052
Type T208RR Pilot (continued)
Key Description Part Number
11 Body Seal O-ring
Nitrile (NBR) 1H993806992
Fluorocarbon (FKM) 1H9938X0012
12 Insert Seal O-ring
Nitrile (NBR) 1B885506992
Fluorocarbon (FKM) 1B8855X0012
13 Disk Assembly
Nitrile (NBR) ERSA01112A0
Fluorocarbon (FKM) ERSA01112A1
14 Stem, Stainless steel ERSA00200A0
16 Lever Assembly, Stainless steel 1B5375000B2
17 Machine Screw (2 required) 19A7151X022
18 Guide Insert, Stainless steel 27B4028X022
22 Closing Cap
Plastic (standard) T11069X0012
Carbon Steel(1) ERSA01809A0
23 Hex Nut (8 required), Steel 1A345724122
24 Cap Screw (8 required), Zinc-plated steel 1A579724052
25 Gasket, Neoprene 1P753306992
26 Vent, Type Y602-11 (spring case up) 17A5515X012
35 Adjusting Screw
Internal Flat Circular 1B537944012
External Square Head(1)
For Green and Light Blue spring 10B3080X012
For Black spring 1D995448702
36 Washer, Plated Carbon steel 18B3440X012
38 Cap Screw, Zinc-plated steel 1B290524052
41 Back Disk Spring, Stainless steel 1E984637022
42 Back Body Seal O-ring
Nitrile (NBR) 13A1584X012
Fluorocarbon (FKM) 13A1584X022
43 Back Body Cap, Stainless steel 1F2737X0012
44 Disk Spacer, Stainless steel ERSA00198A0
45 Lower Head Gasket, Composition 18B3450X012
49 Backup Ring, Stainless steel 18B3446X012
50 Lower Spring Seat, Zinc-plated steel 1B636325062
Key 2, Spring Case Assembly
Key 6, Spring
BODY SIZE,
NPS / DN CONSTRUCTION RELIEF SET PRESSURE RANGE SPRING CASE ASSEMBLY PART NUMBER SPRING PART NUMBER
2 / 50
Type 66R 2 to 8 in. w.c. / 5 to 20 mbar 1D7614X0012 1D765427012
Type 66RR 3 to 8 in. w.c. / 7 to 20 mbar 12A6056X012
Type 66R only
6 to 16 in. w.c. / 15 to 40 mbar
11 in. w.c. to 1 psig / 27 mbar to 0.07 bar
0.75 to 1.5 psig / 0.05 to 0.10 bar
1 to 2 psig / 0.07 to 0.14 bar
1.5 to 3 psig / 0.10 to 0.21 bar
3 to 5 psig / 0.21 to 0.34 bar
1D7614X0022
1D7614X0032
1D7614X0042
1D7614X0052
1D7614X0062
1D4792000A2
1D765527012
1D765627032
1D765727032
1D765827032
1D962627032
1N506427142
3 / 80
Type 66R 2 to 8 in. w.c. / 5 to 20 bar 1D7614X0072 1D770727012
Type 66RR 3 to 8 in. w.c. / 7 to 20 mbar 12A6057X012
Type 66R only
6 to 16 in. w.c. / 15 to 40 mbar
11 in. w.c. to 1 psig / 27 mbar to 0.07 bar
0.75 to 1.5 psig / 0.05 to 0.10 bar
1 to 2 psig / 0.07 to 0.14 bar
1.5 to 3 psig / 0.10 to 0.21 bar
3 to 5 psig / 0.21 to 0.34 bar
1D7614X0082
1D7614X0092
1D7614X0102
1D7614X0112
1D7614X0122
1D5391000A2
1D770827032
1D765727032
1D765827032
1D770927032
1E204427032
1N506527142
4 / 100
Type 66R 2 to 8 in. w.c. / 5 to 20 mbar 1D7614X0132 1D771027012
Type 66RR 3 to 8 in. w.c. / 7 to 20 mbar 12A6058X012
Type 66R only
6 to 16 in. w.c. / 15 to 40 mbar
11 in. w.c. to 1 psig / 27 mbar to 0.07 bar
0.75 to 1.5 psig / 0.05 to 0.10 bar
1 to 2 psig / 0.07 to 0.14 bar
1.5 to 3 psig / 0.10 to 0.21 bar
1D7614X0142
1D7614X0152
1D7614X0162
1D7614X0172
1D7614X0182
1D771127032
1D527627032
1D771227032
1D771327032
1E204527032
*Recommended spare part.
1. Use for optional external square head adjusting screw assembly recommended for 0.9 to
2.5 psig / 62 to 172 mbar, 1.3 to 4.5 psig / 90 to 310 mbar and 3.8 to 7 psig / 0.26 to
0.48 bar spring ranges only.

20
7
19
1
10
11
8
9
13
41
34
15
3
22
32
21
5332439
17
36
40
6
24
25
26
27
23
29
28
30
18
35
37
23
18
15
13
14
16
35
27
25
45
26
24
67
27
26
25
72
40
36
39
4
33
2
21
32
3
15
18
35
41
11
10
1
7
5
64
60
65
63
62
61
17
13
34
22
37
9
8
23
19
20
6
Types 66R and 66RR
11
40A6361-B
30A6359-B
B1433
51A7562_E
APPLY LUBRICANT
SECTION A-A
TYPE T208RR PILOT
COMPLETE STANDARD ASSEMBLY WITH INTERNAL REGISTRATION
CLOSING CAP AND ADJUSTING SCREW DETAIL FOR
3 TO 5 psig / 0.21 to 0.34 bar CONSTRUCTION
DETAIL OF OPTIONAL CAST IRON CONTRUCTION WITH SEALING
DIAPHRAGM AND TAPPED DIAPHRAGM CASE
Figure 6. Type 66R Relief Valve
Figure 7. Type 66RR Main Valve and Pilot Mounting Parts

7
7 8
65
50
10 45 16 17 12 11 49 44 42
36 38 18 14 41
13
35
L1 L1 L1
L2 L2
1
2
4
26
24
23
3
22
25
43
Types 66R and 66RR
Emerson Automation Solutions
Facebook.com/EmersonAutomationSolutions
LinkedIn.com/company/emerson-automation-solutions
Twitter.com/emr_automation
[email protected]
Fisher.com
B2701
B2649_1
Americas
McKinney, Texas 75070 USA
T [phone]
[phone]
Europe
Bologna 40013, Italy
T [phone]
Asia Pacic
Singapore 128461, Singapore
T [phone]
Middle East and Africa
Dubai, United Arab Emirates
T [phone]
D100248X012 © 1980, 2020 Emerson Process Management Regulator
Technologies, Inc. All rights reserved. 02/20.
The Emerson logo is a trademark and service mark of Emerson
Electric Co. All other marks are the property of their prospective owners.
Fisher™ is a mark owned by Fisher Controls International LLC, a
business of Emerson Automation Solutions.
The contents of this publication are presented for informational purposes
only, and while every e󰀨ort has been made to ensure their accuracy, they
are not to be construed as warranties or guarantees, express or implied,
regarding the products or services described herein or their use or
applicability. All sales are governed by our terms and conditions, which
are available upon request. We reserve the right to modify or improve the
designs or specications of such products at any time without notice.
Emerson Process Management Regulator Technologies, Inc does not
assume responsibility for the selection, use or maintenance of any
product. Responsibility for proper selection, use and maintenance of any
Emerson Process Management Regulator Technologies, Inc. product
remains solely with the purchaser.
PILOT INTERIOR ASSEMBLY
PILOT EXTERIOR ASSEMBLY
EXPANDED VIEW OF THE BODY AREA SHOWING
THE BODY SEAL O-RING AND BACKUP RING PLACEMENT
BODY (KEY 1)
BACKUP RING (KEY 49)
BODY SEAL
O-RING (KEY 11)
Figure 8. Type T208RR Pilot Assembly