Cummins/Onan — LPG Regulator Test
Testing & diagnosis · Two-stage LPG regulator
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Before you start
- LP gas is flammable; eliminate ignition sources and provide ventilation
Procedure
- Attach a pressure gauge to the test port on the back of the regulator.
- Attach a pressure hose to the inlet opening and open the air pressure valve.
- If the primary seal is sound, gauge reads approximately 1-1/2 psi (10.3 kPa) and stays constant.
- Close the air pressure valve; pressure should remain constant (a drop means the secondary seat leaks).
- Rebuild or replace the regulator if it fails either test.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Primary pressure approximately 1-1/2 psi (10.3 kPa)
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.