REFERENCE 28-00 · LP GAS SYSTEM
LP Gas Pressure Specs & Timed Leak Test
Reference values from NFPA 1192 (Standard on Recreational Vehicles) practice for regulator output pressure and the timed pressure-drop test. This is diagnostic reference material, not a DIY leak-test walkthrough — gas work should be performed or verified by a certified technician.
⚠ LP gas leaks and improper regulator adjustment can cause fire, explosion, or asphyxiation. This page is reference information only. Leak testing and regulator service should be performed by a certified RV or propane technician with a calibrated manometer.
Operating Pressure
| Stage | Pressure |
|---|---|
| Tank pressure (varies by temp) | ~100–200 psi |
| First stage (two-stage regulator) | ~10–15 psi |
| Second stage / appliance operating pressure | 11″ W.C. (~0.4 psi) |
Most RV appliances are rated for a working range of roughly 10–14″ W.C., with 11″ W.C. as the standard set point. “W.C.” = inches of water column, the standard low-pressure gas measurement.
Lock-Up Pressure
When all burner valves are closed, a healthy regulator’s pressure rises slightly above the 11″ W.C. flow pressure and then stops — this is “lock-up.” A properly functioning regulator should not lock up more than about 30% above the flow pressure. A lock-up reading noticeably higher than that, or one that keeps climbing instead of stopping, indicates a failing regulator diaphragm that needs replacement.
Timed Pressure-Drop Leak Test (NFPA 1192 §5.3.20.6)
Per NFPA 1192, the system pressure-drop test uses a test pressure of not less than 8″ W.C. and not more than 14″ W.C. The standard field practice technicians use:
- Connect a calibrated manometer to the system (commonly at a burner orifice with the valve closed), with all appliance valves shut and pilot lights out.
- Pressurize the system, then let it relax down to a stable 8″ W.C. baseline reading — this settling period allows the regulator diaphragm and system volume to stabilize.
- Isolate the manometer from the supply (close the service valve) and start a timer for a minimum of 3 minutes.
- Read the manometer again. Any drop indicates a leak that must be located (soap-solution test at fittings) and repaired before the system is returned to service. A pressure rise usually indicates ambient temperature change or a valve that isn’t fully seated — not a leak.
This is a certified-technician task. Never test with an open flame, never rely on smell alone, and never return a system to service after a failed test without a proper repair.
Related Reference Pages
⚠ Safety note: This page is for informational purposes only and is not a substitute for the advice of a qualified professional. LP gas systems carry fire, explosion, and asphyxiation risk. Do not attempt leak testing, regulator adjustment, or appliance conversion without proper training and calibrated equipment. If you smell gas, do not operate switches or open flames — shut off the supply, ventilate, and call a certified technician immediately. United Mobile RV LLC is not responsible for outcomes of DIY gas work performed using this reference. Rev. 1 — August 2026.
Suspect a leak or a regulator issue? We test it properly with calibrated equipment, on-site.