Note
backpressure regulator be installed
case is unobstructed at all times. For
or downspouts and be sure it is above
CAUTION
®E-body, damage
if necessary.
Overpressure
Maximum inlet pressures depend upon body
materials and temperatures. Refer to the nameplate
for the maximum inlet pressure of the relief valve
or backpressure regulator. The relief valve or
backpressure regulator should be inspected for
damage after any overpressure condition.
valve or backpressure regulators are NOT ASME
safety relief valves.
Table 1. Type LR128 Main Valve Body Sizes, End Connection Styles, Structural Design Ratings and
Maximum Operating Inlet Pressures(1)
MAIN VALVE
BODY SIZE MAIN VALVE
BODY MATERIAL END CONNECTION STYLE
STRUCTURAL
DESIGN RATING(3)
MAXIMUM OPERATING
RELIEF (INLET)
PRESSURE INCLUDING
BUILD-UP(3)
MAXIMUM
OPERATING OUTLET
PRESSURE
DN In. bar psig bar psig bar psig
25, 50,
80 and
100
1, 2,
3 and
4
WCC Steel
NPT or SWE (1 and 2 in. only) 103 1500 31.0 450 31.0 450
CL150 RF 20.0 290 20.0 290 20.0 290
CL300 RF 51.7 750
31.0 450 31.0 450CL600 RF 103 1500
PN 16/25/40 RF 40.0 580
CF8M
Stainless steel
NPT (1 and 2 in. only) 99.2 1440 31.0 450 31.0 450
CL150 RF 19.0 275 19.0 275 19.0 275
CL300 RF 49.6 720
31.0 450 31.0 450CL600 RF 99.2 1440
PN 16/25/40 RF 40.0 580
1. The pressure/temperature limits in this Installation Guide and any applicable standard or code limitation should not be exceeded.
2. Ratings and end connections for other than ASME standard can usually be provided. Contact your local Sales Ofce for assistance.
3. Maximum cold working pressure (CWP) per ASME B16.34 or product bulletin limit, whichever is lowest. Temperature may decrease these maximum pressures.
Table 2. Type MR98H Pilot Maximum Cold Working Pressure(1)(2)
BODY SIZE BODY AND SPRING CASE MATERIAL MAXIMUM INLET PRESSURE MAXIMUM OUTLET PRESSURE
1/2 NPT Steel or Stainless steel 31.0 bar / 450 psig 31.0 bar / 450 psig
1. The pressure/temperature limits in this Installation Guide and any applicable standard or code limitation should not be exceeded.
2. Temperature and/or the body end connection may decrease these maximum pressures.
Startup
The relief valve or backpressure regulator is factory
set at approximately the midpoint of the spring range
or the pressure requested, so an initial adjustment
may be required to give the desired results. With
proper installation completed and relief valves properly
adjusted, slowly open the upstream and downstream
shutoff valves (if applicable).
To change the outlet pressure, remove closing
cap or loosen the locknut and turn the adjusting
screw clockwise to increase outlet pressure or
counterclockwise to decrease pressure. Monitor
the outlet pressure with a test gauge during the
adjustment. Replace closing cap or tighten the locknut
to maintain the desired setting.
