D103247XUS2
Installation Guide
English – March 2015
Type MR108
www.fisherregulators.com
Introduction
This installation guide provides instructions for
installation, startup and adjustment. To receive a copy
of the instruction manual, contact your local Sales
Office or view a copy at www.fisherregulators.com. For
further information refer to Type MR108 Instruction
Manual, Form 5875, D103247X012.
P.E.D. Category
This product may be used as a pressure accessory
with pressure equipment in the following Pressure
Equipment Directive 97/23/EC categories. It may
also be used outside of the Pressure Equipment
Directive using sound engineering practice (SEP)
per table below.
PRODUCT SIZE
CATEGORY
DN 25 / NPS 1
SEP
DN 50 / NPS 2
II
DN 80 / NPS 3
II
DN 100 / NPS 4
II
Specifications
Available Constructions
Type MR108 with low-pressure actuator:
Direct-operated large multi-purpose backpressure
regulator with 0.34 to 2.4 bar / 5 to 35 psig
pressure range
Type MR108 with high-pressure actuator:
Direct-operated large multi-purpose backpressure
regulator with 1.7 to 20.7 bar / 25 to 300 psig
pressure range
Body Sizes and End Connection Styles
DN 25 and 50 / NPS 1 and 2:
NPT, CL125 FF, CL250 RF, CL150 RF, CL300 RF,
CL600 RF and PN 16/25/40 RF
DN 80 and 100 / NPS 3 and 4:
CL125 FF, CL250 RF, CL150 RF, CL300 RF,
CL600 RF and PN 16 RF
Backpressure Control Ranges
(1)
Low-Pressure Actuator:
0.34 to 0.97 bar / 5 to 14 psig; 0.55 to 1.7 bar /
8 to 24 psig; 0.83 to 2.1 bar / 12 to 30 psig;
1.0 to 2.4 bar / 15 to 35 psig
High-Pressure Actuator:
1.7 to 2.8 bar / 25 to 40 psig; 2.4 to 4.8 bar /
35 to 70 psig; 3.8 to 8.3 bar / 55 to 120 psig;
6.2 to 13.8 bar / 90 to 200 psig
(2)
; 12.1 to 20.7 bar /
175 to 300 psig
(3)
Maximum Set Pressure
(1)
Low-Pressure Actuator:
2.4 bar / 35 psig
High-Pressure Actuator:
Nitrile (NBR) and Ethylene Propylene (EPDM)
Diaphragm:
20.7 bar / 300 psig
Fluorocarbon (FKM) Diaphragm:
10.3 bar / 150 psig
Temperature Capabilities
(1)
Nitrile (NBR):
-29 to 82°C / -20 to 180°F
Fluorocarbon (FKM):
-7 to 121°C / 20 to 250°F
(4)
Ethylene Propylene (EPDM):
-29 to 107°C /
-20 to 225°F
(6)
Maximum Emergency Casing Pressures
(1)(7)
Low-Pressure Actuator:
4.8 bar / 70 psig
High-Pressure Actuator:
27.6 bar / 400 psig
(5)
Maximum Inlet Pressures
(1)(7)
Low-Pressure Actuator:
4.8 bar / 70 psig
High-Pressure Actuator:
27.6 bar / 400 psig
(5)
Maximum Outlet Pressures
(1)(7)
Low-Pressure Actuator:
4.8 bar / 70 psig
High-Pressure Actuator:
27.6 bar / 400 psig
(5)
Maximum Differential Pressures
(1)
Low-Pressure Actuator:
4.8 bar / 70 psig
High-Pressure Actuator:
27.6 bar / 400 psig or
maximum inlet pressure, whichever is lower
Maximum Pressures over Set Pressure to Avoid
Internal Parts Damage
(1)
Low-Pressure Actuator:
1.4 bar / 20 psig
High-Pressure Actuator:
8.3 bar / 120 psig
Installation
!
WARNING
Only qualified personnel should
install or service a backpressure
regulator. Backpressure regulators
should be installed, operated and
maintained in accordance with
international and applicable codes
and regulations and Emerson Process
Management Regulator
Technologies Inc. instructions.
If using a backpressure regulator
on a hazardous or flammable fluid
service, personal injury and property
damage could occur due to fire or
explosion of vented fluid that may
1. The pressure/temperature limits in this Installation Guide or any applicable limitation should not be exceeded.
2. Maximum set pressure is limited to 10.3 bar / 150 psig for constructions with Fluorocarbon (FKM) diaphragm.
3. Not applicable for constructions with Fluorocarbon (FKM) diaphragm.
4. Fluorocarbon (FKM) is limited to 93°C / 200°F hot water.
5. Maximum Inlet, Outlet and Emergency Casing Pressures for constructions with Fluorocarbon (FKM) diaphragm are limited to 15.8 bar / 230 psig or the body rating limit, whichever is lower.
6. Ethylene Propylene (EPDM) is limited to -7 to 107°C / 20 to 225°F when used with Low Pressure Actuator.
7. Pressure ratings are based on a maximum operating temperature of 121°C / 250°F.
