INSTALLATION, OPERATION & MAINTENANCE MANUAL (IOM)
ISO Registered Company
MODEL B7
BACK PRESSURE REGULATOR
SECTION l
I. DESCRIPTION AND SCOPE
The Model B7 is a back pressure regulator used to control upstream (inlet or P1) pressure. Available in
sizes 1/2" and 3/4" (DN15 and DN20) with FNPT, Flanged ends or Tri-Clamp connections. The unit is suitable
for gaseous service. Refer to Technical Bulletin B7-TB for design conditions and selection rec om men da tions.
CAUTION
This is not a safety device and must not be substituted for a code approved pressure safety relief valve
or a rupture disc.
SECTION II
II. INSTALLATION
IOM-B7
03/16
CAUTION
Installation of adequate overpressure pro tec tion
is recommended to pro tect the reg u la tor from
over pres sure and all down stream equip ment from
dam age in the event of regulator failure.
1. An inlet block valve should always be installed.
2. If service application is continuous such that
shut down is not readily accomplished, it is recommended that an inlet block valve, outlet block
valve, and a manual bypass valve be installed.
3. Pipe unions should be installed to allow removal
from piping.
4. An inlet pressure gauge should be located ap proxi mately ten pipe diameters upstream, and
within sight.
5. All installations should include a downstream
re lief de vice if the inlet pressure could exceed the
pres sure rating of any downstream equip ment or
the maximum outlet pressure rating of the unit.
6. Clean the pip ing of all foreign material including
chips, welding scale, oil, grease and dirt before
installing the reg u la tor. Strainers are rec om mend ed.
7. In plac ing thread seal ant on pipe ends pri or to
en gage ment, ensure that excess material is
Recommended Piping Schematic for Back Pressure Regulator
re moved and not allowed to enter the regulator
upon startup.
8. Flow Direction: Install so the flow direction
match es the inlet stamp on the regulator body
(1).
9. For best performance, install in well drained
hori zon tal pipe.
10. Regulator may be rotated around the pipe axis
360°. Recommended position is with knob (20)
or adjusting screw (14) ver ti cal upwards.
11. Regulators are not to be buried un der ground.
12. For insulated piping systems, recommendation
is to not insulate regulator.
SECTION III
III. PRINCIPLE OF OPERATION
1. Movement occurs as pressure variations register on
the piston (5). The registering pressure is the inlet,
, or upstream pressure. The range spring (12)
P
1
opposes piston movement. As inlet pressure drops,
the range spring pushes the piston down, closing the
SECTION IV
IV. STARTUP
CAUTION
port; as inlet pres sure in creas es, the piston pushes
up and the port opens.
2. A piston failure will cause the reg u la tor to fail closed.
6. Continue to slowly open the outlet (downstream)
block valve until fully open.
The maximum inlet pressure is stamped on the
body as the upper range spring pres sure level, and
is the rec om mend ed “upper operative limit” for the
sens ing piston (see Sec tion IV. Startup, Step 7).
Higher press ures could dam age the internals. DO
NOT HYDRO STATIC TEST THRU AN IN STALLED
UNIT; ISO LATE FROM TEST.)
1. Start with the block valves closed. A bypass valve
may be used to maintain inlet pressure in the upstream system without changing the fol low ing steps.
2. Relax the range spring (12) by turning knob (20)
or adjusting screw (14) counter clockwise (CCW) a
minimum of three full rev o lu tions. This reduces the
inlet pres sure setpoint.
3. If it is a “hot” piping system, and equipped with a bypass valve, slowly open the bypass valve to pre-heat
the system piping and to allow slow ex pan sion of the
piping. Closely monitor inlet (up stream) pres sure via
gauge to assure not over-pressurizing. NOTE: If
no bypass valve is in stalled, extra caution should be
used in starting up a cold system; i.e. do everything
slowly.
4. Crack open the inlet (upstream) block valve.
7. Observing the inlet (upstream) pressure gauge, ro tate knob or adjusting screw clockwise (CW) slowly
until the inlet pres sure begins to rise. Rotate CW
until the desired setpoint is reached.
8. Continue to slowly open the inlet (upstream block
valve. If the inlet (upstream) pressure exceeds the
desired setpoint pressure, rotate knob or adjusting
screw CCW until the pres sure decreases.
9. When flow is established steady enough that both
the outlet and inlet block valves are fully open, begin
to slowly close the bypass valve, if installed.
10. Develop system flow to a level near its expected
normal rate, and reset the regulator setpoint by
turn ing knob or adjusting screw CW to increase inlet
pressure, or CCW to reduce inlet pressure.
11. Using a downstream valve, reduce system flow to a
min i mum level and ob serve setpoint. Inlet pres sure
will rise from the setpoint of Step 9. (Ensure this rise
does not exceed the stated upper limit of the range
spring by greater than 50%, i.e. 2-50 psig (.14 - 3.4
Barg) range spring, at maximum flow the inlet pres sure should not exceed 1.5 x 50 psig (3.4 Barg), or
75 psig (5.2 Barg). If it does, consult factory).
5. Slowly open the outlet (downstream) block valve
ob serv ing the inlet (upstream) pressure gauge.
De ter mine if the regulator is flowing. If not, slowly
rotate the regulator knob or adjusting screw CCW
until flow begins.
SECTION V
V. SHUTDOWN
1. On systems with a bypass valve, and where sys tem
pressure is to be main tained as the reg u la tor is shut
down, slowly open the bypass valve while closing the
inlet (up stream) block valve. Fully close the inlet (up stream) block valve. (When on bypass, the sys tem
pres sure must be con stant ly observed and man u al ly
2
12. Increase flow to maximum lev el, if possible. Inlet
(up stream or P
setpoint as necessary at the normal flow rate.
reg u lat ed. Close the outlet (down stream) block
valve.
) pressure should fall off. Re ad just
1
CAUTION
Do not walk away and leave a bypassed regulator
unattended.
IOM-B7
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