North American High Pressure Regulators and Relief Valves
Instructions 7337/7347
Ref: Bulletin 7337A-3, 7337A/B/C-4, 7337-4 and 7347
INSTALLATION
must be in a straight length of pipe, and not after elbows or any other fittings. Using ½ " or ¾ " pipe, connect the underside of the regulator diaphragm case to this connection. Install an 1837D-01 Needle Valve in the pressure sensing line to provide means for pulsation dampening. This valve has an inter- nal orifice which prevents shutoff. DO NOT use a conventional needle valve which can completely shut off the downstream signal and result in a dangerous condition.
Make sure all piping is clean before installing regulator(s). Blow out piping if necessary before installing components.
Inspect regulator for damage and make sure the valve disc and seat are clean.
Most regulators and relief valves may be installed in any posi- tion (gas flow must be in the same direction as the arrow on the valve body.) Exception: It is preferable, but not necessary, that the 7337-4 diaphragm case be mounted over the valve body. This is to prevent the weight of the regulator internals from af- fecting the outlet pressure. Coat male pipe threads lightly with pipe joint compound (ex- cess can migrate to the valve seat and affect operation). If using Teflon tape, do not wrap the first two threads (avoid using tape at all if possible).
7337A-3 and 7347 Regulators
The regulator outlet pipe size must be maintained for 10 pipe diameters before increasing the size. The 7337A-3 piping may then be increased. The 7347 piping may then be increased one pipe size only. CROSS-CONNECTING The 7337A-3 and 7347 Regulators MUST NOT be cross-connect- ed to the air line. To do so will create a hazardous condition because they have internal relief valves. The 7337-4 Regulator vent may be cross-connected to the com- bustion air line downstream of the combustion air control valve for the following reasons: 1) To permit functioning as a ratio regulator. 2) To provide a constant pressure drop across a downstream cross-connected ratio regulator. (Provides more accurate con- trol especially on turndown.) When cross-connecting 7337-4L-1 and -2 Regulators, remove and discard the snap-ring and flapper valve inside the regulator vent connection.
Install unions on both the inlet and outlet of the regulator to facilitate repair or replacement if necessary.
If uninterrupted operation is necessary in the event of a regula- tor failure, install two regulators in parallel. Each regulator will require manual shutoff valves on both inlet and outlet. When installing a regulator, place the pipe wrench only on the end being tightened. Do not tighten from the opposite end as distortion of the regulator body may occur. DOWNSTREAM PIPING 7337-4 Regulators (see Figure 1) The downstream pipe size, should be increased as close to the regulator outlet as possible. A reducing coupling must be used, not a bushing. Measuring 10 pipe diameters downstream of the outlet of the reducing coupling, on the top or side of the pipe, provide a con- nection for a pressure sensing line (see Fig. 1). This connection
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