Installation and Maintenance
Model 121 Regulators
Bypass (if required)
Remote Vent Line (if required)
Vent Cap
1" NPT
Vent
Inlet
Outlet
Control
Connection
Control Line
1/4" NPT (121-8 & 121-12)
1/2" NPT (121-16)
Model 121
5 Pipe
Diameters
8 – 10 Pipe Diameters
3
Temperature Limits
The Model 121 Regulator can be used for flowing temperatures from
-20° F to 150° F.
Buried Service
The Model 121 Regulator is not recommended for buried service.
Set Point Adjustment
A
The 121 is factory adjusted as specified on the order. To change
the set-point, readjust as follows:
1
Remove top cap
1.
2
Adjust set-point with adjustment button
3
or
3a
.
Turn clockwise to increase and counterclockwise to
decrease the outlet pressure.
Note:
a.
Only make this adjustment when gas is actually flowing
through the regulator. The flow should be small
(approximately 1000 SCFH). Do not adjust when the
regulator is closed and there is no flow.
b.
Do not increase the set-point beyond the upper limit of the
outlet pressure range for the spring
9
(refer to spring
tables, Page 4).
c.
Always check the outlet pressure with a pressure gauge
while adjusting the set-point.
3
When adjustment is complete, replace top cap
1
.
Screw it securely into place. Failing to replace cap could
cause unstable regulator operation.
CAUTION
It is the user's responsibility to assure that all regulator vents
and/or vent lines exhaust to a non-hazardous location away from
any potential sources of ignition. Where vent lines are used, it is
the user's responsibility to assure that each regulator is individually
vented and that common vent lines are not used.
To Change Spring
A
The outlet pressure ranges of spring
9
are given in the tables on
Pages 4 and 5. To change the spring:
1
Remove top cap
1
.
2
Unscrew and remove adjustment button
3
or
3a
by turning counterclockwise, and remove spring
9
.
3
Insert new spring. Make sure it is positioned correctly at
the bottom before replacing adjustment button
3
or
3a
.
4
Adjust for the desired outlet pressure per previous section
“Set Point Adjustment.”
5
When adjustment is complete, replace top cap
1
.
Screw it securely into place. Failing to replace
cap could result in unstable regulator operation.
6
New spring range should be marked on regulator.
If old spring range appears on regulator, it should be removed.
CAUTION
The diaphragm case vent must be positioned to protect against
flooding, drain water, ice formation, traffic, tampering, etc.
The vent must be protected against nest building animals, bees,
insects, etc. to minimize the chances for foreign material from
collecting in the vent side of the regulator diaphragm.
Shutdown
A
To Take the regulator out of service, carefully close the
inlet
stop valve first. Then close the
outlet
stop valve. Before
working on regulator, read the next section “General Servicing
Instructions” and the applicable servicing instructions.
CAUTION
Turn gas on very slowly. If an outlet stop valve is used, it should
be opened first. Do not overload diaphragm with a sudden surge
of inlet pressure. Monitor the outlet pressure during start-up to
prevent an outlet pressure overload.
General Servicing Instructions
A
Before any disassembly of the regulator, ensure it is completely
depressured. Pressure must be fully released from the inlet,
the outlet and the control line connection. Failure to adequately
depressure could result in serious personal injury.
B
Carefully note the location and position of all disassembled
parts to be certain reassembly is correct. Inspect each part
carefully and replace any that are worn, damaged or otherwise
unsatisfactory.
C
Upon completion of servicing, make certain that the regulator
installation is entirely free of leaks.
CAUTION
Regulators are pressure control devices with numerous
moving parts, subject to wear and dependent upon particular
operating conditions. To assure continuous satisfactory
operation, a periodic inspection schedule must be adhered
with the frequency of inspection determined by the severity
of service and applicable laws and regulations.
Typical Installation
