Data Sheet

Bulletin 71.4:MR98
2
1. The pressure/temperature limits in this Bulletin and any applicable standard limitation should not be exceeded.
2. Loading pressure plus spring setting should not exceed maximum inlet pressure.
3. Temperature and/or the body end connection may decrease these maximum pressures.
4. Maximum inlet pressure equals set pressure plus build-up.
5. Pressure and/or the body end connection may decrease these maximum temperatures.
6. Not for use on steam service.
7. Meets API 614 Requirements (with Stainless steel trim).
Available Constructions
Type MR98L: Direct-operated low pressure
backpressure regulator/relief valve with 2 to
38 psig / 0.14 to 2.6 bar set pressure range
Type MR98H: Direct-operated high pressure
backpressure regulator/relief valve with 5 to
200 psig / 0.34 to 13.8 bar set pressure range
Type MR98HH: Direct-operated high pressure
backpressure/relief valve with 150 to 375 psig /
10.3 to 25.9 bar set pressure range
Type MR98LD: Pressure-loaded low pressure
differential pressure relief valve with 2 to 38 psi /
0.14 to 2.6 bar set pressure range
Type MR98HD: Pressure-loaded high pressure
differential pressure relief valve with 5 to 200 psi /
0.34 to 13.8 bar set pressure range
Type MR98HHD: Pressure-loaded high pressure
backpressure/relief valve with 150 to 375 psi /
10.3 to 25.9 bar differential set pressure range
Body Sizes and End Connection Styles
See Tables 1 and 2
Main Valve Materials
See Table 5
Trim Materials
See Tables 4 and 5
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1/4 NPT body: 0.284 in. / 7.22 mm
1/2 in. / DN 15 body: 0.416 in. / 10.56 mm
3/4 and 1 in. / DN 20 and 25 bodies:
0.631 in. / 16.02 mm
1-1/2 and 2 in. / DN 40 and 50 bodies:
1.142 in. / 29 mm
Maximum Cold Working Pressures of
Body Size and Material
(1)(3)
See Table 6
Maximum Inlet and Outlet Pressure Ratings
(1)(4)
See Table 6
Relief Pressure Ranges
(1)
See Table 3
Maximum Spring Case Loading Pressure for
Types MR98LD, MR98HD and MR98HHD
(Spring Setting Plus Loading Pressure)
(1)(2)
Type MR98LD Spring Case
Gray Cast Iron: 50 psig / 3.4 bar
Steel or Stainless steel: 125 psig / 8.6 bar
Type MR98HD Spring Case
Gray Cast Iron: 250 psig / 17.2 bar
Steel or Stainless steel: 300 psig / 20.7 bar
Type MR98HHD Spring Case
Steel or Stainless steel: 300 psig / 20.7 bar
Temperature Capabilities for Elastomer Parts
(1)(5)
MATERIAL TEMPERATURE RANGE
Nitrile (NBR) -40 to 180°F / -40 to 82°C
Neoprene (CR) -40 to 180°F / -40 to 82°C
Fluorocarbon (FKM)
(6)
0 to 300°F / -18 to 149°C
Limited to 200°F / 93°C for hot water
Ethylenepropylene (EPDM)
(6)
20 to 275°F / -7 to 135°C
Peruoroelastomer (FFKM)
(6)
0 to 425°F / -18 to 218°C
Polytetrauoroethylene (PTFE)
Diaphragm Protector
-40 to 400°F / -40 to 204°C
Temperature Capabilities of Body Materials
(1)(5)
MATERIAL TEMPERATURE RANGE
Gray Cast Iron -20 to 406°F / -29 to 208°C
LCC Steel
(7)
-40 to 450°F / -40 to 232°C
WCC Steel
(7)
-20 to 450°F / -29 to 232°C
Stainless steel
(7)
, Monel
®
or
Hastelloy
®
C
-40 to 450°F / -40 to 232°C

BODY SIZE
C
v
C
g
C
1
In. DN
1/4 NPT - - - - 1.4 48 34.3
1/2 15 3.4 120 35.3
3/4 and 1 20 and 25 6.5 250 38.5
1-1/2 and 2 40 and 50 20.0 780 39.0
Hastelloy
®
C is a mark owned by Haynes International, Inc.
Monel
®
is a mark owned by Special Metals Corporation.
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This section lists the specications for the MR98 Series regulators. Factory specication such as type, maximum
inlet pressure, maximum temperature, maximum outlet pressure, spring range, orice size and seat material are
stamped on the nameplate fastened on the regulator at the factory.