2
243 Service Regulators Installation and Maintenance Instructions
6. Adjust outlet pressure (setpoint) by removing cap (1) or (1e)
and turning adjustment spring button (3). On the 243-8HP,
remove cap (1a), loosen locknut and turn adjustment screw
(1b). Turn clockwise to increase and counterclockwise to
decrease outlet pressure. Only adjust when gas is fl owing
through the 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.
7. On regualors with an internal relief valve (IRV), there is
no adjustment for the internal relief. It is fi xed, with relief
beginning at approximately 9" w.c. to 20" w.c., above regulator
setpoint, depending on relief spring (11k) used.
Internal relief valves must be carefully sized. For information,
contact your Sensus representative.
8. Regulators installed indoors must be vented outside. Run
vent pipe from the regulator vent connection to a safe place
outside. Vent piping should be as short and direct as possible.
Vent piping for regulators with an internal relief valve (Models
243-12-2 or 243-8-2) must be large enough to vent all relief
valve discharge to atmosphere without excessive back
pressure and resulting excessive pressure in the regulator.
The vent pipe outlet must be protected against nest building
animals, bees, insects, etc., and positioned to protect against
fl ooding, drain water, ice formation, etc. but must allow free
and unobstructed passage of air or gas.
CAUTION
Turn gas on very slowly. If an outlet stop valve is used, it
should be opened fi rst. 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.
Servicing
1. Make sure the regulator is entirely depressured before
disassembling.
2. Carefully note the location and position of all disassembled
parts to be certain that reassembly is correct. Inspect each
part and replace those that are worn or damaged or otherwise
unsatisfactory.
3. For access to valve (21) and orifi ce (24) loosen union bolts
(16) and remove the diaphragm case assembly from the body.
To remove valve (21), fi rst remove hair pin cotter (20b).
Orifi ce (24) unscrews from the body. Use 1⅝" hex socket
“thinwall” type. When replacing the orifi ce, use a moderate
amount of pipe dope on orifi ce threads.
4. Before reassembling and tightening union bolts (16), make
certain Tetraseal (17) is in position.
5. To replace diaphragm, remove spring (4), remove fl ange
bolts (8) and nuts (9), and disassemble diaphragm assembly.
Remove old diaphragm (11a), from diaphragm pan (11b).
Remove old adhesive from the diaphragm pan using a solvent
such a methyl ethyl ketone (MEK).
To reassemble, apply a thin, even layer of a rubber based
adhesive such as 3M Industrial Adhesive #EC-847 to the
cleaned, prepared side of the diaphragm pan.
Attach the diaphragm to the adhesive side of the diaphragm
pan, being careful to align the center hole of the diaphragm
with the corresponding center hole in the diaphragm pan.
Make certain all parts are reassembled in their correct order
and bolts (8) are tightened to a torque of 150 in-lbs. Bolts
must be tight enough to prevent leakage but not too tight
that the diaphragm material is crushed or damaged. The
diaphragm must not be twisted or pinched.
6. 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 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.
IN-G-REG-1306-1212-01-A Z_edited.indd 2 3/7/2013 2:17:26 PM
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