Sensus 243-12-4 User manual

Model 243
Service Regulators
R-1306
Rev. 10

243 Service Regulators
These large capacity service regulators are designed and built
for commercial, industrial and gas distribution work. They are
right at home in such places as factories and foundries, district
regulator stations, commercial laundries and laundromats,
motels-hotels and apartments, bakeries, restaurants, schools,
churches and hospitals.
The versatile 243 is used for all kinds of gas fueled equipment
. . .boilers, burners, furnaces, ovens, heaters, kilns, engines, air
conditioners, etc.
Remarkable field versatility results from the union connection
between the fully interchangeable bodies and diaphragm-case
assemblies. They are easy to install, adjust, inspect and serv-
ice in all kinds of piping arrangements.
While used primarily for natural gas services, Model 243 regu-
lators perform equally well on LPG vapor, air, dry CO2, nitrogen
and other inert gas applications. Contact your representative
for special construction which may be available for certain cor-
rosive gases.
2
Basic Models
Outlet Pressure
Ranges and Springs
Pipe Sizes
243-12
Model Numbers
243-8
Model Numbers
Variation
243-12-1
243-12-2
243-12-4
243-12-6
Standard* Regulator
Regulator with Internal Relief Valve (IRV)
Regulator with Low Pressure Cut-Off (LPCO)
Regulator with both IRV and LPCO
High Pressure Regulator
Pressure Loaded Regulator
243-8-1
243-8-2
243-8-4
243-8-6
243-8HP
243-8PL
For additional information on IRV refer to page 5. For LPCO refer to page 6
*The term standard refers to non-IRV configurations.
Spring Color 243-12 243-8
Outlet Pressure Range Spring Part Number
Red-Black
Blue-Black
Green-Black
Red
Blue
Green
Orange-Black
Orange
Black
Cadmium
Cadmium
Cadmium
White t
---
---
---
31⁄2” to 61⁄2” w.c.
5” to 81⁄2” w.c.
6” to 14” w.c.
10” to 18” w.c.
12” to 28” w.c.
1 to 2 psi
11⁄2to 3 psi
11⁄2to 3 psi
---
---
143-82-021-00
143-82-021-01
143-16-021-02
143-16-021-03
143-16-021-04
143-16-021-05
143-16-021-11
143-16-021-06
143-16-021-07
143-16-021-08
143-16-021-08
143-16-021-08
143-16-021-13
tWhite is nested inside Cadmium *Model 243-8HP only
◆
◆
Model 243-8-2 (IRV) only.
Model Pipe Size
243-12-1
and
243-12-2
243-8-1
and
243-8-2
243-8HP
11⁄4”,1⁄2”
and 2”
11⁄4”,11⁄2”
and 2”
11⁄4”,11⁄2”
and 2”
Temperature Limits
The Model 243 Regulator may be used for flowing gas
temperatures from -20oF to 150oF.
Buried Service
The Model 243 Regulator is not recommended for buried service.
Copyright 2007, Sensus Metering Systems
31⁄2” to 61⁄2” w.c.
5” to 81⁄2” w.c.
6” to 14” w.c.
---
---
12” to 28” w.c.
---
1 to 2 psi
2 to 41⁄2psi
3 to 5 psi
◆
◆
3 to 61⁄2psi*
6 to 10 psi*

3
Maximum Inlet
Pressure, psig
Fixed Factor billing
11⁄4”
30o
15
15
15
-
-
-
-
-
-
11⁄4”, 243-12
11⁄2”, 243-12
2”, 243-12
11⁄4”, 243-8
11⁄2”, 243-8
2”, 243-8
11⁄4”, 243-8HP
11⁄2”, 243-8HP
2”, 243-8HP
*11⁄4”
10o
25
25
25
-
-
-
-
-
-
1”
30o
25
25
25
-
25
25
-
25
25
1⁄2”
10o
100
100
100
80
80
80
80
80
80
3⁄8”
10o
125
125
125
100
100
100
100
100
1⁄4”
10o
125
125
125
125
125
125
125
125
125
.207”
10o
-
-
-
125
125
-
-
-
-
*1”
10o
40
40
40
-
-
-
-
-
-
3⁄4”
30o
-
-
40
-
-
40
-
-
-
3⁄4”
10o
60
60
60
40
40
40
40
40
*External Control Regulator Only
Regulator
Model
and Size
Regulator accuracy is essen-
tial to measurement accuracy,
and because the 243 is so
precise, it is ideal for Pres-
sure-Factor Measurement,
Pressure Compensated
Metering, Fixed Factor Billing,
etc.
The table below gives the
pressure accuracies obtain-
able with 243-12 and 243-8
regulators at the capacities in
the tables on pages 8 to 19.
The 243 will hold outlet pres-
sure within the indicated per-
centage limits from set flow
(250 scfh) to the flows given in
the capacity tables. Percent-
ages are all based on
absolute pressure using 14.4
psia as atmospheric.
As an example, referring to
page 10, a 11⁄2” Model 243-12-
2 with 1” orifice, 30o, valve, 15
psig inlet and 11” w.c. set-
point (green spring) at 2” w.c.
droop has a gas capacity of
9800 scfh. Per the below
table, this regulator at these
conditions will hold outlet
pressure at 11” w.c. = 1⁄2% (2”
w.c.) from 250 to 9800 scfh
(based on absolute pressure).
For higher outlet pressures,
greater capacities, increased
accuracies, and excessive
inlet pressure variations, use
the 243-RPC pilot operated
regulator (see page 7).
Set Point
6” w.c.
7” w.c.
11” w.c.
18” w.c.
1psi
1psi
2psi
3psi
3psi
Droop
1” w.c.
1” w.c.
2” w.c.
3” w.c.
0.3 psi
0.2 psi
0.6 psi
0.3 psi
0.6 psi
Accuracy
+ 1⁄2% and -1⁄2%
+ 1⁄2% and -1⁄2%
+ 1⁄2% and -1⁄2%
+ 1% and -1%
+ 1% and -2%
+ 1% and -11⁄2%
+ 1% and -4%
+ 1% and -2%
+ 1% and -31⁄2%

Construction and Design Features
4
Model 243-8-1
Model 243-12-1
Travel Stop
Vent
•1” NPT
2-Way Vent Valve
• Fast Response on
Rapid Load Change
4 Bolt Union Connection
•Easily Removable, Fast Off and On
•Full 360oRotation for Best
Diaphragm Assembly Position
•Easy Access for Valve Inspection
and Servicing
Interchangeable
Diaphragm
Assemblies
Molded Valve
•Buna-N Disc in
Aluminum Holder
Interchangeable
Brass Orifices
Cast Iron Bodies
(ASTM A126-81 Class B)
Die Cast Aluminum Alloy
Diaphragm Case
• Light Weight
• High Strength
• Corrosion Resistant
A travel stop is located in the
243-12-1 and the 243-12-4 to
provide overpressurization
protection.
Caution: Turn gas on slowly. If an outlet stop valve is used, it should be opened first. Do
not overload the diaphragm with a sudden surge of inlet pressure. Monitor the outlet
pressure during start-up to prevent an outlet pressure overload. Refer to RM-1306 for
more detailed start-up procedures.
Diaphragm
• Buna-N with
Nylon Fabric
Reinforcement
Pipe Sizes
2”, 11⁄2”, 11⁄4” NPT Screwed*
2” Flanged ANSI 125
*Can also be furnished with British Standard Threads (BST)

Operation of the
Internal Relief Valve
5
The internal relief valve is
optional (refer to Basic Models
Table, page 2).
Often called an “IRV”, it is built
into the center of the
diaphragm assembly as
shown in the adjoining sketch
and works in essentially the
same way as standard relief
valves.
It opens when outlet pressure
exceeds the setpoint by
approximately 9” w.c. thereby
allowing excess gas to
escape through the vent to
atmosphere. An optional
spring is available on the 243-
8-2 for relieving at approxi-
mately 20” w.c. above set
point. A cross-section of a
complete 243 with IRV is
shown on page 6.
Performance is given on the
curves at the right. The IRV
will prevent the outlet pres-
sure from exceeding the value
shown by the curves upon
regulator failure at the condi-
tions specified.
The IRV is a proven design of
quality construction. Within its
capacity limits it adds a meas-
ure of safety protection to the
outstanding and dependable
performance of the 243.
Caution: Note that an IRV, like any other relief valve, must be sized carefully. If the curves indicate that outlet pressure can
exceed the maximum safe limit it is essential to provide an additional relief valve carefully sized to handle the difference.

243 Variations
6
Internal Relief Valve
The 243 is available with an internal relief valve (IRV). It’s a
built-in safety device for providing a limited level of overpressur-
ization protection.
Like any relief valve, an IRV must be carefully sized.
More complete description plus performance data is given on
page 5. For Basic Models refer to the table on page 2.
Internal Relief valves are not available in the high pressure
Model 243-8HP
Low Pressure Cut-Off
The low pressure cut-off (LPCO) is used for automatic gas shut-
off when inlet pressure is too low for the required gas flow. Once
closed, it must be manually reopened and reset.
Basic Models are given in the table at the bottom on page 2.
Note: There is an LPCO version that also includes the internal
relief valve.
Outlet pressures range from 4” w.c. to 30” w.c. and available ori-
fices are 1⁄2”, 3⁄4” and 1”. For more complete information and
capacities please refer to data bulletin RDS 1306-1.
Pressure Loading
While pressure loading (self-operation) falls short of the remark-
able accuracy inherent in the pilot operated regulator (relay-
operation) it still does a good job. And the pressure loaded 243-
8PL has a performance background of many years of depend-
able, accurate pressure control.
Its outlet range is 3 to 35 psig. Pipe sizes are 11⁄4”, 11⁄2” and 2”.
It is available arranged either bleed to atmosphere or bleed to
line. Capacities range to over 50,000 scfh.

7
Monitoring and
External Control Line
This 243 is used for the first regulator (upstream regulator) in a
monitor set or for other applications requiring an external down-
stream control line.
A throat block with an o-ring stem seal isolates the lower
diaphragm chamber which has a 1⁄2”FNPT connection for the
external control line.
Use of this regulator for monitoring is shown on page 20.
Capacities with the external control line are provided on pages
12 and 13.
Pilot Operated Regulator
The 243-RPC is a genuine pilot operated regulator. It works on
exactly the same relay-operation principle as the widely used
models 1100 and 1200, and the 441-VPC.
Like its bigger brothers, it not only provides remarkably precise
pressure regulation but it maintains that high level of accuracy
even for wide variations in inlet pressure.
The 243-RPC can be used for any outlet pressure from 31⁄2” w.c.
to 35 psig with capacity ranging as high as 75,000 scfh.
For detailed information please refer to Bulletin R-1343.

Model 243 Capacity Tables
2” Models 243-12-1 and 243-12-2 in SCFH of Natural Gas (0.6 Specific Gravity - 14.65 psia - 60ºF)
8
Outlet Pressure
and Spring
Set Point 6” w.c.
1” w.c. Droop
Red Spring
31⁄2” to 61⁄2” w.c.
143-16-021-03
Set Point 7” w.c.
1” w.c. Droop
Blue Spring
5” to 81⁄2” w.c.
143-16-021-04
Set Point 11” w.c.
2” w.c. Droop
Green Spring
6” to 14” w.c.
143-16-021-05
Inlet
Pressure
psi
11⁄4”1” 3⁄4”3⁄4”1⁄2”3⁄8”1⁄4”
30o30o30o10o10o10o10o
Orifice Size and Valve Angle
1⁄2
1
2
5
10
15
25
40
60
80
100
125
1⁄2
1
2
5
10
15
25
40
60
80
100
125
1
2
5
10
15
25
40
60
80
100
125
2400
4000
6400
11000
13000
14000
2000
3400
6000
11000
12500
14000
3400
5600
10500
13000
14000
2200
3600
6000
11000
15000
15000
15000
1800
3000
5600
11000
14000
15000
15000
3000
4700
9000
13000
14000
15000
1500
2700
4500
8200
12500
15000
20000
20000
1400
2200
4000
8000
12000
15000
20000
20000
2100
3700
7800
12000
15000
20000
20000
1250
2100
3800
6500
9000
10300
11500
13000
15000
1100
2000
3200
6000
8400
10000
11500
13500
15000
1950
3400
6900
9200
10500
12000
14500
15500
800
1300
2200
3800
5700
7100
9500
13000
13000
13000
13000
700
1200
2000
3700
5600
7100
9500
12000
13000
13000
13000
1150
2000
3500
5500
7000
9500
12500
13000
14000
14000
500
850
1400
2300
3300
4000
5300
7500
10000
12000
12000
12000
500
750
1250
2100
3300
4000
5300
7500
10000
12000
12000
12000
750
1200
2100
3200
4000
5300
7500
10000
12000
12000
12000
400
600
1000
1500
1750
2400
3300
4500
5700
7000
8000
400
600
1000
1400
1750
2400
3200
4400
5600
7000
8000
400
600
1000
1600
1800
2400
3200
4400
5600
7000
8000
Note: The performance data is based on normal testing at 70ºF flowing temperature.
Changes in performance can occur at extreme low flowing temperatures.
Last capacity figure in each group indicates maximum allowable inlet pressure (except for emergency conditions). Heavy
stepped line indicates the recommended maximum capacity and inlet pressure for each orifice for operation within the
optimum performance range.

Model 243 Capacity Tables
9
2” Models 243-12-1 and 243-12-2 in SCFH of Natural Gas (0.6 Specific Gravity - 14.65 psia - 60ºF) (continued)
Outlet Pressure
and Spring
Set Point 18” w.c.
3” w.c. Droop
Orange Spring
12” to 28” w.c.
143-16-021-06
Set Point 1 psi
0.31 psi Droop
Orange Spring
12” to 28” w.c.
143-16-021-06
Set Point 1 psi
0.2 psi Droop
Black Spring
1 to 2 psi
143-16-021-07
Set Point 2 psi
0.6 psi Droop
Cadmium Spring
11⁄2to 3 psi
143-16-021-08
Set Point 3 psi
0.35 psi Droop
Cadmium Spring
11⁄2to 3 psi
143-16-021-08
Inlet
Pressure
psi
11⁄4”1” 3⁄4”3⁄4”1⁄2”3⁄8”1⁄4”
30o30o30o10o10o10o10o
Orifice Size and Valve Angle
1
2
5
10
15
25
40
60
80
100
125
2
5
10
15
25
40
60
80
100
125
2
5
10
15
25
40
60
80
100
125
5
10
15
25
40
60
80
100
125
5
10
15
25
40
60
80
100
125
2500
4200
8000
12000
13500
6500
8000
9000
12000
3350
6600
11000
13000
8200
12500
15500
3500
8000
10500
2000
3400
7100
12000
14500
16500
5000
7500
8500
11000
13500
3000
5900
10000
12000
15000
7400
11300
14500
18000
3000
7000
10000
11500
1400
2700
5600
10500
15000
20000
20000
4000
6000
8000
10000
12500
14000
2000
4200
7600
9300
16500
20000
5200
8700
11500
16500
20000
2000
5500
8000
9800
21500
1200
2400
4700
7500
9500
11500
13500
15000
4000
6000
8000
10000
11500
13000
15000
1900
3900
6500
8300
11000
14000
15500
4800
7800
10000
13500
16500
16500
1800
5000
7000
9000
20000
21000
950
1500
2800
4800
6500
9200
12000
13000
14000
14000
2000
4000
5500
7000
9500
11000
13500
15000
16000
1200
2400
4100
5600
8500
12500
13000
14000
14000
2900
4800
6500
9000
12500
15500
16000
16000
1400
3000
4000
5600
10500
14500
18000
20500
650
1000
1800
2900
3900
5300
7500
10000
12000
12000
12000
1300
2200
3000
4000
5500
7400
10000
13000
14000
14000
1000
1600
2800
3800
5300
7500
10000
12000
12000
12000
1900
3000
3800
5300
7600
10000
12000
12000
12000
1100
2000
3000
4500
7500
10500
13500
16400
19000
500
950
1400
1700
2300
3200
4400
5600
7000
8000
500
1000
1400
1800
2400
3300
4500
6000
7000
8500
500
1000
1450
1700
2400
3400
4400
5600
7000
8000
900
1400
1700
2400
3400
4600
5600
7000
8000
750
1100
1600
2000
3500
4500
6000
7500
9000
Note: The performance data is based on normal testing at 70ºF flowing temperature.
Changes in performance can occur at extreme low flowing temperatures.
Last capacity figure in each group indicates maximum allowable inlet pressure (except for emergency conditions). Heavy
stepped line indicates the recommended maximum capacity and inlet pressure for each orifice for operation within the
optimum performance range.

Model 243 Capacity Tables
10
11⁄2” Models 243-12-1 and 243-12-2 in SCFH of Natural Gas (0.6 Specific Gravity - 14.65 psia - 60ºF)
Outlet Pressure
and Spring
Set Point 6” w.c.
1” w.c. Droop
Red Spring
31⁄2”to 61⁄2”w.c.
143-16-021-03
Set Point 7” w.c.
1” w.c. Droop
Blue Spring
5” to 81⁄2” w.c.
143-16-021-04
Set Point 11“ w.c.
2” w.c. Droop
Green Spring
6” to 14” w.c.
143-16-021-05
Set Point 18” w.c.
3” w.c. Droop
Orange Spring
12” to 28” w.c.
143-16-021-06
Inlet
Pressure
psi
11⁄4”1” 3⁄4”1⁄2”3⁄8”1⁄4”
30o30o10o10o10o10o
Orifice Size and Valve Angle
1⁄2
1
2
5
10
15
25
40
60
80
100
125
1⁄2
1
2
5
10
15
25
40
60
80
100
125
1
2
5
10
15
25
40
60
80
100
125
1
2
5
10
15
25
40
60
80
100
125
2000
2800
4000
6100
8200
9300
1800
2600
3800
5700
8200
9300
2700
4000
6000
8800
10000
1800
3000
5600
8600
10000
1600
2500
3500
5600
7700
9300
11000
1550
2300
3300
5100
7600
9100
11000
2300
3500
5600
8200
9800
11500
1300
2800
5200
7700
9300
11500
1300
2100
3200
4800
6500
7400
9100
10500
12000
1100
1850
2600
4200
6000
7000
8400
10000
10500
1900
2700
4500
6500
7700
9700
11500
12500
1100
2200
4200
6000
7400
9100
11000
12500
700
1200
2100
3700
5600
6800
8100
9800
11000
12000
12000
600
1100
1900
3300
5400
6600
7800
9500
10500
11500
12000
1100
1900
3500
5500
6800
8100
9700
11500
12000
12500
800
1500
2600
4300
5800
7800
9500
11000
12500
13000
500
800
1300
2200
3100
3900
5100
7100
9300
10500
11000
11000
500
750
1250
2100
3100
3900
5100
7100
9300
10500
11000
11000
750
1200
2100
2900
3800
5100
7100
9300
10500
11000
11000
500
1000
1800
2900
3800
5100
7100
9300
10500
11000
11000
400
600
1000
1400
1750
2400
3200
4400
5600
7000
8000
400
600
1000
1400
1750
2400
3200
4400
5600
7000
8000
400
600
1000
1400
1750
2400
3200
4400
5600
7000
8000
500
950
1400
1750
2400
3200
4400
5600
7000
8000
Note: The performance data is based on normal testing at 70ºF flowing temperature.
Changes in performance can occur at extreme low flowing temperatures.
Last capacity figure in each group indicates maximum allowable inlet pressure (except for emergency conditions). Heavy
stepped line indicates the recommended maximum capacity and inlet pressure for each orifice for operation within the
optimum performance range.

Model 243 Capacity Tables
11
11⁄2” Models 243-12-1 and 243-12-2 in SCFH of Natural Gas (0.6 Specific Gravity - 14.65 psia - 60ºF) (cont’d.)
Outlet Pressure
and Spring
Set Point 1 psi
0.31 psi Droop
Orange Spring
12” to 28” w.c.
143-16-021-06
Set Point 1 psi
0.2 psi Droop
Black Spring
1 to 2 psi
143-16-021-07
Set Point 3 psi
0.35 psi Droop
Cadmium Spring
11⁄2to 3 psi
143-16-021-08
Set Point 2 psi
0.6 psi Droop
Cadmium Spring
11⁄2to 3 psi
143-16-021-08
Inlet
Pressure
psi
11⁄4”1” 3⁄4”1⁄2”3⁄8”1⁄4”
30o30o10o10o10o10o
Orifice Size and Valve Angle
2
5
10
15
25
40
60
80
100
125
2
5
10
15
25
40
60
80
100
125
5
10
15
25
40
60
80
100
125
5
10
15
25
40
60
80
100
125
6500
8000
9000
12000
2800
5500
8000
10000
3500
7000
9000
6000
10000
13000
5000
7500
8500
11500
13500
2450
5100
7500
9100
11000
3000
6000
8000
10000
5300
9300
12000
14500
4000
6000
8000
10000
11500
13000
15000
1500
3700
5700
7100
9300
11000
12500
2000
5000
7000
8000
11500
14000
4100
7100
8800
11000
13500
15000
2000
4000
5500
7000
9500
11000
13500
15000
16000
1200
2400
4000
5300
7300
9300
11000
12500
13000
1400
2500
3500
4800
6500
8000
9000
12000
2700
4700
6200
8600
11000
13500
15000
16000
1300
2200
3000
4000
5500
7400
10000
13000
14000
14000
850
1600
2700
3700
5100
7100
9300
10500
11000
11000
1100
2000
2500
4500
6000
7500
8000
11000
12000
1700
2900
3800
5200
7100
10000
12000
12000
12000
500
1000
1400
1800
2400
3300
4500
6000
7000
8500
500
950
1400
1750
2400
3200
4600
5600
7000
8000
500
1000
1500
1900
3500
4500
6000
7000
8500
900
1400
1700
2400
3200
4600
5600
7000
8000
Last capacity figure in each group indicates maximum allowable inlet pressure (except for emergency conditions). Heavy
stepped line indicates the recommended maximum capacity and inlet pressure for each orifice for operation within the
optimum performance range.
Note: The performance data is based on normal testing at 70ºF flowing temperature.
Changes in performance can occur at extreme low flowing temperatures.

Orifice Size and Valve Angle
Model 243 Capacity Tables
12
11⁄4”, 11⁄2” and 2” Model 243-12-1 with External Control Line in SCFH of Natural Gas
(0.6 Specific Gravity - 14.65 psia - 60ºF)
Outlet Pressure
and Spring
Set Point 6” w.c.
1” w.c. Droop
Red Spring
31⁄2” to 61⁄2” w.c.
143-16-021-03
Set Point 7” w.c.
1” w.c. Droop
Blue Spring
5” to 81⁄2” w.c.
143-16-021-04
Set Point 11 “ w.c.
2” w.c. Droop
Green Spring
6” to 14” w.c.
143-16-021-05
Inlet
Pressure
psi
11⁄4”* 1” 3⁄4”1⁄2”3⁄8”1⁄4”
10o10o10o10o10o10o
1⁄2
1
2
5
10
15
25
40
60
80
100
125
1⁄2
1
2
5
10
15
25
40
60
80
100
125
1
2
5
10
15
25
40
60
80
100
125
2200
3600
5600
10500
15000
19000
22000
2000
3100
5000
7800
13000
15000
20000
3200
5200
8500
13500
16000
20000
1900
3200
4700
8200
12000
16000
20000
24000
1700
2600
3800
6500
10000
14000
17000
21000
2500
4200
7200
11000
14000
17000
24000
1600
2300
3500
5700
8900
12000
16000
21000
27000
1500
2000
3000
5000
7000
9400
13500
17000
19000
1900
3200
5200
8000
11000
14000
21000
25000
800
1300
2000
3500
5200
6700
9000
12000
15500
17000
19000
700
1100
1700
3100
4800
6400
8500
11500
15000
17000
19000
1100
1800
3200
5000
6500
9000
12000
15000
17000
19000
500
850
1400
2200
3000
4000
5200
7500
10000
12000
13500
15000
450
750
1200
2000
2900
4000
5200
7500
10000
12000
13500
15000
700
1300
2000
3000
4000
5200
7000
9800
12000
13500
15000
400
600
1000
1500
1750
2400
3200
4400
5700
7000
8000
400
600
1000
1500
1750
2400
3200
4400
5700
7000
8000
350
550
1000
1500
1750
2400
3200
4400
5700
7000
8000
Note: The performance data is based on normal testing at 70ºF flowing temperature.
Changes in performance can occur at extreme low flowing temperatures.
Last capacity figure in each group indicates maximum allowable inlet pressure (except for emergency conditions). Heavy
stepped line indicates the recommended maximum capacity and inlet pressure for each orifice for operation within the
optimum performance range.
* 2” Body Only.

Model 243 Capacity Tables
13
11⁄4”, 11⁄2” and 2” Model 243-12-1 with External Control Line in SCFH of Natural Gas
(0.6 Specific Gravity - 14.65 psia - 60ºF) (cont’d.)
Outlet Pressure
and Spring
Set Point 18” w.c.
3” w.c. Droop
Orange Spring
12” to 28” w.c.
143-16-021-06
Set Point 1 psi
0.2 psi Droop
Black Spring
1 to 2 psi
143-16-021-07
Set Point 2 psi
0.6 psi Droop
Cadmium Spring
11⁄2to 3 psi
143-16-021-08
Inlet
Pressure
psi
11⁄4”* 1” 3⁄4”1⁄2”3⁄8”1⁄4”
10o10o10o10o10o10o
Orifice Size and Valve Angle
1
2
5
10
15
25
40
60
80
100
125
2
5
10
15
25
40
60
80
100
125
5
10
15
25
40
60
80
100
125
2400
4200
6500
11000
14500
18000
3500
7000
10500
14500
18000
8600
13000
17500
25000
2000
3200
5500
8000
11000
15000
21000
2900
5400
8500
10500
14500
20000
6800
10500
13500
20000
25000
1200
2000
4100
6200
8000
11500
15000
20000
1700
4000
5800
7600
10500
15000
20000
5300
7500
10500
14000
20000
25000
900
1500
2700
4200
5800
8000
11000
15000
17000
19000
1300
2600
4000
5400
7500
10500
15000
17000
19000
2700
4500
6000
8500
12000
15000
17000
19000
600
1000
1600
2800
3800
5000
7000
9800
12000
13500
15000
850
1600
2800
3800
5000
7000
9800
12000
13500
15000
1900
2900
3800
5000
7000
10000
12000
13500
15000
300
500
950
1500
1750
2400
3200
4400
5700
7000
8000
500
950
1500
1750
2400
3200
4400
5700
7000
8000
850
1400
1750
2400
3200
4400
5700
7000
8000
Last capacity figure in each group indicates maximum allowable inlet pressure (except for emergency conditions). Heavy
stepped line indicates the recommended maximum capacity and inlet pressure for each orifice for operation within the
optimum performance range.
*2” Body Only.
Note: The performance data is based on normal testing at 70ºF flowing temperature.
Changes in performance can occur at extreme low flowing temperatures.

Model 243 Capacity Tables
14
Orifice Size and Valve Angle
11⁄2” and 2” Model 243-8-1 and 243-8-2 in SCFH of Natural Gas
(0.6 Specific Gravity - 14.65 psia - 60ºF)
Outlet Pressure
and Spring
Set Point 6” w.c.
1” w.c. Droop
Red-Black Spring
31⁄2” to 61⁄2” w.c.
143-82-021-00
Set Point 7” w.c.
1” w.c. Droop
Blue-Black Spring
5” to 81⁄2” w.c.
143-82-021-01
Set Point 11 “ w.c.
2” w.c. Droop
Green-Black Spring
6” to 14” w.c.
143-82-021-02
Inlet
Pressure
psi
1” 3⁄4”1⁄2”3⁄8”1⁄4” 0.207”
30o10o10o10o10o10o
1⁄2
1
2
5
10
15
25
40
60
80
100
125
1⁄2
1
2
5
10
15
25
40
60
80
100
125
1
2
5
10
15
25
40
60
80
100
125
1100
1950
3200
5200
7400
9100
12500
1000
1600
2700
4800
7000
9100
12500
1650
2700
4800
7000
9000
11000
900
1600
2400
3900
5800
7100
8700
10500
750
1150
1800
3500
5400
7000
8700
10500
1150
2000
3800
5400
7400
8800
11000
700
1050
1550
2700
4500
5800
7200
9200
11000
11500
650
900
1350
2350
3900
5000
6600
9000
11000
11500
1000
1400
2600
4200
5500
7500
9600
11000
11500
500
750
1000
1900
3000
3800
5100
7100
9300
10500
11000
400
650
950
1600
2500
3500
5100
7100
9300
10500
11000
650
1000
1750
2800
3600
5100
7100
9300
10500
11000
350
550
950
1350
1700
2400
3200
4400
5600
7000
8000
300
450
770
1250
1700
2400
3200
4400
5600
7000
8000
300
450
900
1300
1700
2400
3200
4400
5600
7000
8000
350
550
900
1150
1500
2100
2900
3700
4500
5600
350
500
900
1150
1500
2100
2900
3700
4500
5600
350
600
900
1100
1500
2100
2900
3700
4500
5600
Note: The performance data is based on normal testing at 70ºF flowing temperature.
Changes in performance can occur at extreme low flowing temperatures.
Last capacity figure in each group indicates maximum allowable inlet pressure (except for emergency conditions). Heavy
stepped line indicates the recommended maximum capacity and inlet pressure for each orifice for operation within the
optimum performance range.

Model 243 Capacity Tables
15
11⁄2” Models 243-8-1 and 243-8-2 in SCFH of Natural Gas (0.6 Specific Gravity - 14.65 psia - 60ºF)
Outlet Pressure
and Spring
Set Point 18” w.c.
3” w.c. Droop
Green Spring
12” to 28” w.c.
143-16-021-05
Set Point 1 psi
0.31 psi Droop
Green Spring
12” to 28” w.c.
143-16-021-05
Set Point 1 psi
0.2 psi Droop
Orange Spring
1 to 2 psi
143-16-021-06
Set Point 3 psi
0.35 psi Droop
Black Spring
2 to 41⁄4psi
143-16-021-07
Inlet
Pressure
psi
1” 3⁄4”1⁄2”3⁄8”1⁄4” 0.207”
30o10o10o10o10o10o
Orifice Size and Valve Angle
1
2
5
10
15
25
40
60
80
100
125
2
5
10
15
25
40
60
80
100
125
2
5
10
15
25
40
60
80
100
125
5
10
15
25
40
60
80
100
125
5
10
15
25
40
60
80
100
125
1500
2100
4500
6600
8800
11500
4000
6000
7500
9000
12000
2100
4000
6500
8400
11000
3000
4000
5200
7000
4400
7100
9600
12500
1100
1700
3400
5700
7100
9100
11000
3500
5000
7000
8000
10000
12500
1650
3200
5200
6500
8600
11000
1800
2500
4000
5200
9000
3400
5900
7500
10500
13000
800
1300
2000
3500
5000
7100
9300
11000
12000
1800
3500
5000
6500
8000
9500
11500
12500
1200
2100
3100
4400
6500
8600
10500
11500
1200
1800
2850
3600
5000
8300
10000
2400
3600
4800
6500
9600
12500
13500
550
900
1350
2400
3400
5100
7100
9400
10500
11000
1200
2200
3000
4000
5000
7000
9500
11500
12500
850
1300
2200
3000
4400
6700
9000
10500
11000
1100
1500
2000
3100
4200
6500
8500
9000
1600
2400
3400
5000
7000
9300
11000
12000
450
850
1300
1700
2400
3200
4400
5600
7000
8000
500
1000
1500
1850
2000
3000
4500
6000
7000
8000
450
850
1300
1700
2400
3200
4400
5600
7000
8000
900
1000
1400
1800
2200
3000
5000
6000
8000
800
1300
1700
2400
3200
4400
5600
7000
8000
350
600
850
1050
1500
2100
2900
3700
4500
5600
550
800
1000
1500
2100
2900
3700
4500
5600
750
1000
1500
2100
2900
3700
4500
5600
Last capacity figure in each group indicates maximum allowable inlet pressure (except for emergency conditions). Heavy
stepped line indicates the recommended maximum capacity and inlet pressure for each orifice for operation within the
optimum performance range.
Note: The performance data is based on normal testing at 70ºF flowing temperature.
Changes in performance can occur at extreme low flowing temperatures.
Set Point 3 psi
0.6 psi Droop
Black Spring
2 to 41⁄4psi
143-16-021-07

Model 243 Capacity Tables
16
Orifice Size and Valve Angle
11⁄4” Models 243-8-1, 243-8-2, 243-12-1 and 243-12-2 in SCFH of Natural Gas
(0.6 Specific Gravity - 14.65 psia - 60ºF)
Outlet Pressure
and Spring
243-8
Set Point 6” w.c.
1” w.c. Droop
Red-Black Spring
31⁄2” to 61⁄2” w.c.
143-82-021-00
Set Point 7” w.c.
1” w.c. Droop
Blue-Black Spring
5” to 81⁄2” w.c.
143-82-021-01
Set Point 11 “ w.c.
2” w.c. Droop
Green-Black Spring
6” to 14” w.c.
143-82-021-02
Set Point 18” w.c.
3” w.c. Droop
Green Spring
12” to 28” w.c.
143-16-021-05
Outlet Pressure
and Spring
243-12
Set Point 6” w.c.
1” w.c. Droop
Red Spring
31⁄2” to 6” w.c.
143-16-021-03
Set Point 7” w.c.
1” w.c. Droop
Blue Spring
5” to 81⁄2” w.c.
143-16-021-04
Set Point 11 “ w.c.
2” w.c. Droop
Green Spring
6” to 14” w.c.
143-16-021-05
Set Point 18” w.c.
3” w.c. Droop
Orange Spring
12” to 28” w.c.
143-16-021-06
Inlet
Pressure
psi
3⁄4”1⁄2”3⁄8”1⁄4” 0.207”
10o10o10o10o10o
1⁄2
1
2
5
10
15
25
40
60
80
100
125
1⁄2
1
2
5
10
15
25
40
60
80
100
125
1
2
5
10
15
25
40
60
80
100
125
1
2
5
10
15
25
40
60
80
100
125
900
1600
2250
2500
3100
3550
4200
4200
750
1150
1700
2300
2900
3500
4200
4800
1150
1850
2500
2900
3700
4250
5300
1100
1900
2250
2950
3450
4400
5300
700
1050
1500
2200
2900
3600
3800
4100
4800
5600
650
900
1300
1900
2600
3100
3600
4000
4600
5600
1000
1350
2200
2700
3950
4000
4200
4850
5850
800
1250
1700
2250
3600
3750
4100
4800
4850
500
750
1000
1900
2650
2700
3300
3800
4400
5600
6000
400
650
950
1600
2200
2500
3300
3800
4400
5600
6000
650
1000
1750
2450
2600
3300
3800
4400
5600
6000
500
900
1350
2100
2450
3300
3800
4400
5600
6000
350
550
950
1350
1700
2400
3200
4400
5600
6000
6000
300
450
770
1250
1700
2400
3200
4400
5600
6000
6000
300
450
800
1300
1700
2400
3200
4400
5600
7000
8000
450
750
1300
1700
2400
3200
4400
5600
7000
8000
350
550
900
1050
1500
2100
2900
3700
4500
5600
350
500
900
1050
1500
2100
2900
3700
4500
5600
350
550
900
1100
1500
2100
2900
3700
4500
5600
350
550
850
1050
1500
2100
2900
3700
4500
5600
Note: The performance data is based on normal testing at 70ºF flowing temperature.
Changes in performance can occur at extreme low flowing temperatures.
Last capacity figure in each group indicates maximum allowable inlet pressure (except for emergency conditions). Heavy
stepped line indicates the recommended maximum capacity and inlet pressure for each orifice for operation within the
optimum performance range.
NOTE: 1” x 30” and 11⁄4” x 30” orifice and valve angle are available on the 11⁄4” 243-12-1 and 243-12-2 models.

Model 243 Capacity Tables
17
Orifice Size and Valve Angle
11⁄4” Models 243-8-1, 243-8-2, 243-12-1 and 243-12-2 in SCFH of Natural Gas
(0.6 Specific Gravity - 14.65 psia - 60ºF) (continued)
Outlet Pressure
and Spring
243-8
Set Point 1 psi
0.31 psi Droop
Green Spring
12” to 28” w.c.
143-16-021-05
Set Point 1 psi
0.2 psi Droop
Orange Spring
1 to 2 psi
143-16-021-06
Set Point 3 psi
0.35 psi Droop
Black Spring
2 to 41⁄4psi
143-16-021-07
Set Point 3 psi
0.6 psi Droop
Black Spring
2 to 41⁄4psi
143-16-021-07
Outlet Pressure
and Spring
243-12
Set Point 1 psi
0.31 psi Droop
Orange Spring
12” to 28” w.c.
143-16-021-06
Set Point 1 psi
0.2 psi Droop
Black Spring
1 to 2 psi
143-16-021-07
Set Point 3 psi
0.35 psi Droop
Cadmium Spring
11⁄2to 3 psi
143-16-021-08
Set Point 3 psi
0.6 psi Droop
Cadmium Spring
11⁄2to 3 psi
143-16-021-08
Inlet
Pressure
psi
3⁄4”1⁄2”3⁄8”1⁄4” 0.207”
10o10o10o10o10o
2
5
10
15
25
40
60
80
100
125
2
5
10
15
25
40
60
80
100
125
5
10
15
25
40
60
80
100
125
5
10
15
25
40
60
80
100
125
3000
4000
5000
6000
7500
8000
1850
2100
2700
3150
4150
5300
1200
2000
3300
4700
6300
2200
3600
3800
5000
6300
1800
3000
4000
5100
6400
7400
8000
8500
1150
1700
2000
3100
3250
3800
4600
4650
1000
1800
2800
3300
4900
5800
6500
1950
2300
3400
3900
4300
5500
5500
1200
2000
3000
3900
4500
6100
7350
8000
8500
850
1350
1950
2050
2850
3600
4250
5600
6000
800
1400
1800
2300
2800
5000
6400
6500
1650
2150
2350
3250
3700
4400
5850
6550
500
1000
1500
1900
2200
2600
4000
5100
6500
7000
450
750
1300
1700
2400
3200
4400
5600
7000
8000
500
1000
1400
1650
2000
2800
4600
4750
5000
700
1300
1700
2400
3200
4400
5600
7000
8000
500
800
1000
1500
2100
2900
3700
4500
5600
750
1000
1500
2100
2900
3700
4500
5600
Note: The performance data is based on normal testing at 70ºF flowing temperature.
Changes in performance can occur at extreme low flowing temperatures.
Last capacity figure in each group indicates maximum allowable inlet pressure (except for emergency conditions). Heavy
stepped line indicates the recommended maximum capacity and inlet pressure for each orifice for operation within the
optimum performance range.
NOTE: 1” x 30º and 11⁄4” x 30º orifice and valve angle are available on the 11⁄4” 243-12-1 and 243-12-2 models.

Model 243 Capacity Tables
18
2” Models 243-8-1 and 243-8-2 in SCFH of Natural Gas (0.6 Specific Gravity - 14.65 psia - 60ºF)
Outlet Pressure
and Spring
Set Point 18” w.c.
3” w.c. Droop
Green Spring
12” to 28” w.c.
143-16-021-05
Set Point 1 psi
0.31 psi Droop
Green Spring
12” to 28” w.c.
143-16-021-05
Set Point 1 psi
0.2 psi Droop
Orange Spring
1 to 2 psi
143-16-021-06
Set Point 3 psi
0.35 psi Droop
Black Spring
2 to 41⁄4psi
143-16-021-07
Set Point 3 psi
0.6 psi Droop
Black Spring
2 to 41⁄4psi
143-16-021-07
Inlet
Pressure
psi
1” 3⁄4”3⁄4”1⁄2”3⁄8”1⁄4”
30o30o10o10o10o10o
Orifice Size and Valve Angle
1
2
5
10
15
25
40
60
80
100
125
2
5
10
15
25
40
60
80
100
125
2
5
10
15
25
40
60
80
100
125
5
10
15
25
40
60
80
100
125
5
10
15
25
40
60
80
100
125
1500
2400
5500
9400
12000
14500
5000
8000
14000
16500
17700
2400
4000
7000
11000
14500
2000
4000
5800
7500
4400
7600
11000
15000
1200
1800
3700
8400
12000
17500
20000
4000
7000
12800
14000
16900
18000
1800
3400
6000
9000
15000
17500
1600
3000
4200
5200
9100
3400
6000
9000
15000
17500
1100
1700
3500
6000
8100
10000
12000
4000
7000
10000
13900
15000
16500
1700
3300
5400
7000
10000
12000
1600
3000
4000
5000
9000
3300
5800
7500
10500
13000
800
1250
2300
3700
5600
8200
11500
13500
14000
3000
4000
5500
7750
9000
11500
15000
17000
1200
2200
3500
4600
7400
10500
12500
13500
1400
2000
2600
3900
6500
10000
14000
2400
3600
4800
8000
11000
14000
15000
600
950
1400
2400
3800
5600
7400
10000
11000
12000
1000
1900
3000
4500
5500
7400
10000
13800
14000
850
1300
2200
3100
4800
7000
9500
10500
11000
1000
1400
1800
2750
5800
7500
10000
12000
1600
2400
3500
5100
7000
9600
11000
12000
500
900
1400
1700
2400
3400
4600
5600
7000
8000
500
1000
1500
1800
2500
3200
4600
6100
7000
9000
450
900
1400
1700
2400
3400
4600
5600
7000
8000
500
1000
1500
2300
3100
4600
6000
7000
9000
800
1300
1700
2400
3400
4600
5600
7000
8000
Note: The performance data is based on normal testing at 70ºF flowing temperature.
Changes in performance can occur at extreme low flowing temperatures.
Last capacity figure in each group indicates maximum allowable inlet pressure (except for emergency conditions). Heavy
stepped line indicates the recommended maximum capacity and inlet pressure for each orifice for operation within the
optimum performance range.

Model 243 Capacity Tables
19
Inlet
Pressure
psi
11
⁄4” Model 243-8HP
Orifice Size and Valve Angle
11 ⁄2” Model 243-8HP
Orifice Size and Valve Angle
2” Model 243-8HP
Orifice Size and Valve Angle
Outlet Pressure
Set Point
5 psi
1 psi Droop
Cadmium
Spring
3to 6 1⁄2psi
143-16-021-08
Set Point
7psi
1psi Droop
Cadmium-
White
Springs
6to 10 psi
143-16-021-03
Set Point
7 psi
2 psi Droop
Cadmium
White
Springs
6 to 10 psi
143-16-021-03
Set Point
10 psi
1 psi Droop
Cadmium-
White
Springs
6 to 10 psi
143-16-021-03
Set Point
10 psi
2 psi Droop
Cadmium-
White
Springs
6 to 10 psi
143-16-021-03
10
15
25
40
60
80
100
125
10
15
25
40
60
80
100
125
10
15
25
40
60
80
100
125
15
25
40
60
80
100
125
15
25
40
60
80
100
125
3300
3400
4400
5800
2300
3000
5400
7600
5400
7400
10000
12500
2500
4800
7200
6000
9000
12000
2050
3100
3650
3800
4400
4500
2000
2800
4100
5600
7500
8800
3500
5000
7600
10000
12500
14000
2200
3500
5000
6700
7800
4000
6500
9000
12000
13000
2000
2200
3050
3200
4100
5300
6000
1800
2200
3300
4800
6200
7200
8600
2500
3500
5500
7500
9500
11500
13500
1800
2800
4000
5700
6600
7800
2800
5000
7000
9400
11000
13000
1300
1700
2400
3200
4400
5600
7000
8000
1000
1400
2000
2800
3800
5200
5800
7000
1400
1800
2500
3500
4800
6100
7200
8800
1200
1900
2500
3500
4600
5400
6500
1700
2500
3500
4700
6000
7000
8800
6000
8600
12000
2500
5000
8500
8000
10500
15000
3500
6500
8500
12000
5500
6500
9300
12000
2300
4000
6500
9500
5500
8000
12000
16000
3000
5000
8000
10500
6500
10500
15000
3200
4400
6100
8500
10000
11000
2000
2500
4300
6500
9000
11000
3500
5000
8000
11500
15000
17500
2000
3500
5500
7500
9000
4000
7000
10000
14000
17000
2300
3200
4800
6100
8700
10000
11000
1600
2200
3500
5000
6500
8500
10500
2500
3500
5000
7500
9500
12500
15500
1300
2500
4300
6000
7500
9500
2500
4500
7500
10000
12000
15000
1300
1700
2400
3200
4400
5600
7000
8000
1000
1500
2000
3000
4000
5000
5500
5500
1300
1700
2300
3300
4500
5500
7000
7000
1000
1900
2500
3500
4500
6000
7000
1500
2300
3000
4500
5500
7000
9000
6000
8600
13000
2700
5900
8600
8600
12700
18600
3600
6800
9000
15500
5500
6000
8200
12000
2500
4300
6600
10000
6000
8900
13500
19000
3000
5700
8600
6600
11000
16500
3200
4400
6100
8700
10000
11500
2100
2800
4600
7200
9700
12000
4300
5700
8600
12500
17000
20000
2000
4000
5700
8600
10500
4800
7400
11000
15000
18500
2400
3200
4800
6100
8700
10000
11000
1600
2400
3600
5600
7000
9000
11500
2700
3800
5700
8000
10000
13500
16500
1800
3000
4600
6400
8400
10700
3000
5000
7700
10700
13000
16000
1300
1700
2400
3400
4600
5600
7000
8000
1000
1500
2000
3000
4500
5500
7000
5500
1400
1800
2400
3500
4800
6200
7300
8100
1000
1900
2800
4300
5200
6500
8000
1500
2400
3200
4800
6000
7300
9000
3
⁄4”
10o
1⁄2”
10o
3
⁄8”
10o
1⁄4”
10o
1”
30o
3
⁄4”
10o
1⁄2”
10o
3
⁄8”
10o
1⁄4”
10o
1”
30o
3
⁄4”
10o
1⁄2”
10o
3
⁄8”
10o
1⁄4”
10o
Last capacity figure in each group indicates maximum allowable inlet pressure (except for emergency conditions). Heavy stepped line indicates the recommended
maximum capacity and inlet pressure for each orifice for operation within the optimum performance range.
Note: The performance data is based on normal testing at 70ºF flowing temperature.
Changes in performance can occur at extreme low flowing temperatures.
Model 243-8HP in SCFH of Natural Gas (0.6 Specific Gravity - 14.65 psia - 60ºF)

20
Maximum Emergency
Pressures
NOTE: The use of an internal
or external relief valve is rec-
ommended for installations
subjected to no flow for
extended periods of time, such
as pilotless ignition systems.
A travel stop stem is located in
the 243-12-1 and 243-12-4 to
provide over-pressurization
protection to internal compo-
nents during overpressuriza-
tion.
The maximum pressure the regu-
lator inlet may be subjected to
under abnormal conditions with-
out causing damage to the regu-
lator is the maximum allowable
inlet pressure (from the capacity
tables, pages 8 through 19) plus
50 psi.
The maximum pressure the
diaphragm may be subjected to
without causing damage to the
internal parts of the regulator is:
243-12-1......... set point + 3 psi
243-12-2, 243-8-1 and
243-8-2........... set point + 5 psi
243-8HP........ set point + 5 psi
Set point is defined as the outlet
pressure a regulator is adjusted
to deliver.
If any of the pressure limits are
exceeded, the regulator must be
taken out of service and inspect-
ed. All damaged or otherwise
unsatisfactory parts must be
repaired or replaced.
The maximum pressure that
can be safely contained by the
diaphragm case is:
243-12-1 and
243-12-2........................ 15 psi
243-8-1 and 243-8-2...... 15 psi
243-8HP....................... 25 psi
Safely contained means no
leakage as well as no bursting
Before using any of the above
data, make sure this entire sec-
tion is clearly understood.
Overpressurization
Protection
Protect the downstream piping
system and the regulator’s low
pressure chambers against over-
pressurization due to possible
regulator malfunction or failure to
achieve positive lockup. The
allowable outlet pressure is
the lowest of the maximum
pressures permitted by fed-
eral codes, state codes, Bul-
letin RDS-1498 or other
applicable standards. The
method of protection can be a
relief valve, monitor regulator,
shut-off device or similar
mechanism.
Monitoring A monitor set consists of two reg-
ulators in series as shown. The
monitor is the standby. It takes
control if a failure in the operating
regulator causes outlet pressure
to exceed normal.
Either regulator may be used as
the monitor. In both cases the
upstream regulator must have a
blocked throat and external con-
trol line as shown for the 243 on
page 7. Also, the control line for
the upstream regulator connects
into the outlet piping all the way
downstream. . . that is, down-
stream of the downstream regu-
lator.
The illustration shows a typical
243 monitor set. While the
downstream regulator is shown
as operating and the upstream
regulator is shown as the moni-
tor, the two can be reversed.
There are reasons for doing it
one way or the other depending
on user’s practice. Stop and
bypass valves, not shown, like-
wise would depend on user’s
preference and practice.
Either way, the operating regulator
is adjusted for the normal outlet
pressure. The monitor is adjusted
somewhat higher so it is normally
full open. If a failure in the
operating regulator causes
excessive increase in outlet
pressure, the monitor will go
into operation to hold outlet
pressure at its set point.
Monitoring is an effective and
dependable method of provid-
ing overpressure protection.
A significant advantage is that
it provides the protection with-
out wasting gas to atmos-
phere. Refer to Bulletin RDS-
1306-2 (Package monitor sets
243-DOT) for more informa-
tion.
When a 243 is used to monitor
another 243 with an identical
orifice size, the total maximum
capacity through both can be
figured at 70% of the rated
capacity for one regulator.
This applies with the monitor
located upstream or down-
stream.
Periodic Inspection: Regulators are pressure control devices with numerous moving parts sub-
ject to wear that is dependent upon particular operating conditions. To assure continuous
satisfactory operation, a periodic inspection schedule must be adhered to with the frequency
of inspection determined by the severity of service and applicable laws and regulations.
See Bulletin RM-1306 field service instructions.