AbsolutAire 243-12 Installation 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

Basic Models

243-12

Model Numbers

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

Outlet Pressure
Ranges and Springs

For additional information on IRV refer to page 5. For LPCO refer to page 6
*The term standard refers to non-IR

Spring Color

Red-Black

V configurations.

Blue-Black
Green-Black
Red
Blue
Green
Orange-Black
Orange
Black
Cadmium
Cadmium
Cadmium

t

White

tWhite is nested inside Cadmium *Model 243-8HP only

Model Pipe Size

Pipe Sizes

243-12-1
and
243-12-2

243-8-1
and
243-8-2

243-8HP

1

1

⁄4”,1⁄2”

and 2”

1

⁄4”,11⁄2”

1
and 2”

1

1

⁄4”,11⁄2”

and 2”

assemblies. They are easy to install, adjust, inspect and serv­ice in all kinds of piping arrangements.

While used primarily for natural gas services, Model 243 regu­lators perform equally well on LPG vapor, air, dry CO

, nitrogen

2

and other inert gas applications. Contact your representative
for special construction which may be available for certain cor­rosive gases.

Variation

243-8

Model Numbers

243-8-1
243-8-2
243-8-4
243-8-6
243-8HP
243-8PL

Outlet Pressure Range

243-12 243-8

---

---

---

31⁄2” to 61⁄2” w.c.

1

5” to 8

⁄2” w.c.

6” to 14” w.c.
10” to 18” w.c.
12” to 28” w.c.

1 to 2 psi

1

⁄2 to 3 psi

1

1

1

⁄2 to 3 psi

---

---

31⁄2” to 61⁄2” w.c.

1

5” to 8

⁄2” w.c.

6” to 14” w.c.

---

---

12” to 28” w.c.

---

1 to 2 psi

1

⁄2 psi

2 to 4

◆

3 to 5 psi

◆

3 to 61⁄2 psi*

6 to 10 psi*

◆

◆

Model 243-8-2 (IRV) only.

Spring Part Number

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

Temperature Limits

The Model 243 Regulator may be used for flowing gas
temperatures from -20

o

F to 150oF.

Buried Service

The Model 243 Regulator is not recommended for buried service.

2

Copyright 2007, Sensus Metering Systems

Maximum Inlet
Pressure, psig

*External Control Regulator Only

Regulator

Model

and Size

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”
30

15
15
15

1

3

3

40

40

3

⁄4”

o

10

-

60

-

60

60

­40

­40

40

­40

-

-

40

⁄2”

⁄4”

o

o

10

100
100
100

80
80
80
80
80
80

10

125

125

125

100

100

100

100

100

*11⁄4”

o

10

-

-

-

-

-

-

25
25
25

1”

25
25
25

25
25

25
25

*1”

o

o

10

30

40
40
40

-

-

-

-

-

-

-

-

o

30

-

-

-

-

-

-

1

⁄8”

⁄4”

10

125
125
125
125
125
125
125
125
125

.207”

o

10

-

-

­125
125

-

-

-

-

o

o

Fixed Factor billing

Regulator accuracy is essen­tial to measurement accuracy,
and because the 243 is so
precise, it is ideal for Pres­sure-Factor Measurement,
Pressure Compensated
Metering, Fixed Factor Billing,
etc.

The table below gives the
pressure accuracies obtain­able with 243-12 and 243-8
regulators at the capacities in
the tables on pages 8 to 19.

Set Point

6” w.c.
7” w.c.

11” w.c.

.c.

18” w

1psi
1psi
2psi
3psi
3psi

The 243 will hold outlet pres­sure within the indicated per­centage limits from set flow
(250 scfh) to the flows given in
the capacity tables. Percent­ages are all based on
absolute pressure using 14.4
psia as atmospheric.

Droop

1” w.c.
1” w.c.
2” w.c.

.c.

3” w

0.3 psi

0.2 psi

0.6 psi

0.3 psi

0.6 psi

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. set­point (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).

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%

3

Construction and Design Features

Model 243-8-1

2-Way Vent Valve

• Fast Response on
Rapid Load Change

Vent

1” NPT

•

Interchangeable
Diaphragm
Assemblies

4 Bolt Union Connection

Easily Removable, Fast Off and On

•
Full 360

•

Easy Access for Valve Inspection

•

o

otation for Best

R

iaphragm Assembly Position

D

nd Servicing

a

Molded Valve

Buna-N Disc in

•
luminum Holder

A

Model 243-12-1
Travel Stop

Diaphragm

• Buna-N with
Nylon Fabric
Reinforcement

Die Cast Aluminum Alloy
Diaphragm Case

• Light Weight

• High Strength

• Corrosion Resistant

Interchangeable
Brass Orifices

A travel stop is located in the
243-12-1 and the 243-12-4 to
provide overpressurization
protection.

Cast Iron Bodies

(ASTM A126-81 Class B)

Pipe Sizes

2”, 11⁄2”, 11⁄4” NPT Screwed*

2” Flanged ANSI 125

*Can also be furnished with British Standard Threads (BST)

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

4

more detailed start-up procedures.

Operation of the
Internal Relief Valve

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 243­8-2 for relieving at approxi­mately 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 pres­sure from exceeding the value
shown by the curves upon
regulator failure at the condi­tions specified.

The IRV is a proven design of
quality construction. Within its
capacity limits it adds a meas­ure of safety protection to the
outstanding and dependable
performance of the 243.

, like any other relief valve, must be sized carefully

Caution: Note that an IR
exceed the maximum safe limit it is essential to provide an additional relief valve carefully sized to handle the dif

V

. If the curves indicate that outlet pressure can

ference.

5

243 Variations

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 overpressur­ization protection.

Like any relief valve, an IRV must be carefully sized.

ore complete description plus performance data is given on

M
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 shut­off 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 ori­fices are
capacities please refer to data bulletin RDS 1306-1.

1

⁄2”, 3⁄4” and 1”. For more complete information and

Pressure Loading

While pressure loading (self-operation) falls short of the remark­able accuracy inherent in the pilot operated regulator (relay­operation) it still does a good job. And the pressure loaded 243­8PL has a performance background of many years of depend­able, accurate pressure control.

1

Its outlet range is 3 to 35 psig. Pipe sizes are 1
It is available arranged either bleed to atmosphere or bleed to
line. Capacities range to over 50,000 scfh.

⁄4”, 11⁄2” and 2”.

6

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 down­stream control line.

A throat block with an o-ring stem seal isolates the lower

iaphragm chamber which has a

d

xternal control line.

e

Use of this regulator for monitoring is shown on page 20.
Capacities with the external control line are provided on pages
12 and 13.

1

FNPT connection for the

⁄2”

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.

1

The 243-RPC can be used for any outlet pressure from 3
to 35 psig with capacity ranging as high as 75,000 scfh.

For detailed information please refer to Bulletin R-1343.

⁄2” w.c.

7

Model 243 Capacity Tables

2” Models 243-12-1 and 243-12-2 in SCFH of Natural Gas

Outlet Pressure

and Spring

Set Point 6” w.c.
1” w.c. Droop
Red Spring
31⁄2” to 61⁄2” w.c.

43-16-021-03

1

Inlet

Pressure

psi

1

⁄2
1
2
5

10
15

1

⁄4”1”3⁄4”

1

o

30

2400
4000

6400
11000
13000
14000

25
40
60

80
100
125

1

2000

10

15

⁄2

3400

1

6000

2

11000

5

12500
14000

Set Point 7” w.c.
1” w.c. Droop
Blue Spring
5” to 81⁄2” w.c.

143-16-021-04

25

40

60

80
100
125

3400

10

15

1

5600

2

10500

5

13000
14000

Set Point 11” w.c.
2” w.c. Droop
Green Spring
6” to 14” w.c.

143-16-021-05

25

40

60

80
100
125

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.

Orifice Size and Valve Angle

o

30

2200
3600

6000
11000
15000
15000
15000

1800

3000

5600
11000
14000
15000
15000

3000

4700

9000
13000
14000
15000

(0.6 Specific Gravity - 14.65 psia - 60ºF)

30

1500
2700
4500

8200
12500
15000
20000
20000

3

o

⁄4”

o

10

1250
2100
3800
6500

9000
10300
11500
13000
15000

1

⁄2”

o

10

800
1300
2200
3800
5700
7100
9500

13000
13000
13000
13000

3

⁄8”

10

500

850
1400
2300
3300
4000
5300
7500

10000
12000
12000

12000
1400
2200
4000
8000

12000
15000
20000
20000

1100
2000
3200
6000

8400
10000
11500
13500
15000

700
1200
2000
3700
5600
7100
9500

12000
13000
13000
13000

500

750
1250
2100
3300
4000
5300
7500

10000
12000
12000

12000
2100
3700
7800

12000
15000
20000
20000

1950
3400
6900

9200
10500
12000
14500
15500

1150
2000
3500
5500
7000

9500
12500
13000
14000
14000

750
1200
2100
3200
4000
5300
7500

10000
12000
12000
12000

1

o

⁄4”

o

10

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.

8

Changes in performance can occur at extreme low flowing temperatures.