RM-1306-1 Rev. 11
Regulator Installation and
Maintenance Instructions
243 Service
Regulators
Introduction
The 243 is a large capacity general-purpose gas pressure
regulator.
Its outstanding performance and versatility make it an excellent
choice for use on industrial meter sets, combustion equipment,
boilers, burners, unit heaters, furnaces, ovens and other appli-
cations.
Use it for natural gas, air, dry CO
2
, propane, butane, L.P.G.,
nitrogen, and others. Special materials are available for cer-
tain corrosive gases.
In addition to the standard models and internal relief models
covered in this bulletin, the 243 is also available with low pres-
sure cut-off, with built-in monitor, and as a pilot operated regu-
lator (outlet pressures to 35 psig), a back pressure valve, a
relief valve, a vacuum regulator and a vacuum breaker. For
information, please contact your Sensus Sales Office or
authorized industrial distributor. The 243 is manufactured in
conformance with Code B31.8.
Note: The term standard refers to Non-IRV configurations.
Model Specifications
243-12-1 and 243-12-2
Maximum Inlet Pressure.........................................125 psi
Outlet Pressures......................................3
1
⁄
2
” w.c. to 3 psi
Pipe Sizes................................................ 1
1
⁄
4
”, 1
1
⁄
2
” and 2”
Diaphragm..................................... 12” (nominal diameter)
243-8-1 and 243-8-2
Maximum Inlet Pressure.........................................125 psi
Outlet Pressures..................................3
1
⁄
2
” w.c. to 4
1
⁄
4
” psi
Pipe Sizes................................................ 1
1
⁄
4
”, 1
1
⁄
2
” and 2”
Diaphragm....................................... 8” (nominal diameter)
243-8HP
Maximum Inlet Pressure.........................................125 psi
Outlet Pressures................................................3 to 10 psi
Pipe Sizes................................................ 1
1
⁄
4
”, 1
1
⁄
2
” and 2”
Diaphragm....................................... 8” (nominal diameter)
Maximum Inlet Pressures
* Applies only to 243-12 with external control line.
t
80 psi for 243-12 with external control line
Temperature Limits
The Model 243 Service Regulators can be used for flowing
temperatures from -20 F to 150 F.
Buried Service
The Model 243 Service Regulators are
not
recommended for
buried service.
Installation and Start Up
(See Illustrations on Page 3.)
1. Make certain that regulator and piping are free of dirt,
moisture, foreign matter and other debris.
2. Be sure all shipping screens or covers are removed and
regulator is installed with flow in correct direction.
3. Regulator may be installed in any position; right-side-up, up-
side down, vertical pipe, horizontal pipe, diagonal pipe, etc.
By loosening union bolts
(16)
, the diaphragm case assembly
may be rotated to various positions in relation to the body.
Make certain
(16)
are re-tightened to hold diaphragm case
assembly in new position and to reseal.
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 prevent vent
blockage and minimize the chances for
foreign material from collecting in the vent
side of the regulator diaphragm.
4. Make sure there are no leaks and all connections are firm
and tight. Tighten flange bolts evenly and firmly. On screwed
connections apply pipe dope to male threads only.
5. On regulators arranged for External Control Line, run pipe
or tubing from
1
⁄
2
” NPT connection in lower case to the con-
trol connection in the outlet piping. This control piping
should not be less than
1
⁄
2
” in size and should be adequately
protected against breakage (regulators go wide open if the
control line is broken). In general, the control connection
should be at least 8 pipe diameters from the regulator and in
as straight a run of pipe as possible. The connection itself
must be smooth on the inside of the pipe. Pitch the control
line away from the regulator and avoid moisture pockets.
Keep inside of control line clean. Never install any type of
automatic shut-off device, which closes completely, between
the regulator outlet and the control line connection.
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 line are
used, it is the user’s responsibility to assure
that each service regulator is individually vented
and that common vent lines
are not
used.
6. Adjust outlet pressure (set point) by removing cap
(1)
or
(1e)
and turning adjustment spring button
(3)
. On 243-8 HP
remove cap
(1a)
, loosen locknut and turn adjustment screw
(1b)
. Turn clockwise to increase and counter-clockwise to
decrease outlet pressure. Only adjust when gas is flowing
through regulator. When adjustment is completed, seal cap
(1)
or
(1e)
must be securely screwed into place. The
absence of this seal cap can result in unstable operation.
243-12
15 psi
25 psi
25 psi
40 psi
40 psi
60 psi
100 psi
125 psi
125 psi
• • •
243-8
• • •
• • •
25 psi
25 psi
40 psi
40 psi
80 psi
100 psi
125 psi
125 psi
1
1
⁄
4
” - 30
1
1
⁄
4
” - 10
1” - 30
1” - 10
3
⁄
4
” - 30
3
⁄
4
” - 10
1
⁄
2
” - 10
3
⁄
8
” - 10
1
⁄
4
” - 10
.207” - 10
t
ORIFICE SIZE - VALVE
O
O
O
O
O
O
O
O
O
O
O
O
*
*
