Propane leaks in an RV are no small matter—they’re a major life safety issue. A leak can lead to dangerous fumes, fire hazards, or worse. That’s why it’s essential for every RV owner and technician to know how to properly test a propane system for leaks.
In this week’s Tech Tip Tuesday from the National RV Training Academy (NRVTA)—America’s largest hands-on RV training school—we’re walking through how to perform a time pressure drop test, one of the most reliable ways to find leaks in an RV propane system.
Step 1: Understanding the Time Pressure Drop Test
The time pressure drop test helps determine if propane is escaping from anywhere in the system—at fittings, connections, valves, or even within appliances.
The test works by:
- Pressurizing all propane lines in the RV.
- Shutting off the propane supply.
- Monitoring the system pressure over a set time window.
If the pressure drops during that time, it indicates a leak somewhere in the propane system.
Step 2: Safety First
Before performing any test, make sure the propane supply is completely turned off. Double-check with another person if possible. Propane is highly flammable, and it’s crucial to control every step.
Next, ensure all propane-burning appliances—such as your furnace, water heater, and refrigerator—are turned off. You don’t want any of these devices calling for gas during testing, as that can interfere with readings or cause ignition hazards.
Step 3: Setting Up Your Equipment
This test is typically performed using a dial manometer—a device that measures pressure in inches of water column. In this example, we’re using a Yellow Jacket brand manometer, pre-calibrated for propane.
You’ll also need a burner spud fitting, which connects the manometer’s rubber hose to the stove manifold. This allows the manometer to read system pressure directly from the RV’s propane lines.
- Remove the stove’s burner cover (usually two Phillips screws).
- Attach the spud fitting to the manifold and connect the manometer hose.
- Confirm all burner knobs are in the OFF position.
Step 4: Charging the Lines
To “charge” the lines:
- Turn the propane on for about five seconds, then shut it back off.
This fills the system with gas pressure for testing.
Now, open one of the stove burner valves to allow pressure into the manometer. The needle will rise to around 11 to 12 inches of water column (WC)—that’s the standard pressure for RV propane systems.
Next, slowly lower that reading to 8 inches of water column. This relaxation phase allows the regulator diaphragms to settle and the pressure to equalize throughout the system.
Step 5: The 3-Minute Test
Once your system is set to 8 inches WC, start your timer for three minutes.
Take a quick photo of the gauge reading as your baseline.
During this time, carefully observe the manometer:
- If the pressure remains steady, you’re in the clear—no leaks detected.
- If it drops, you’ve got a leak that needs to be located and repaired.
Propane expands about 1.5% for every 10°F increase, so testing within a short window helps prevent false readings due to temperature changes.
For accuracy, many technicians perform the test two or three times to confirm results. If a leak is suspected, recheck your manometer and hose connections before moving to the RV system itself.
Step 6: Verify After Repairs
Once any repair or replacement has been made, always repeat the time pressure drop test. This ensures your work didn’t introduce a new leak.
In addition, spray a liquid leak detector (a non-chlorinated, non-ammonia solution) on all connection points you’ve touched. If bubbles form, that fitting isn’t sealed properly and must be tightened or redone.
Avoid using soaps with chlorine or ammonia—they can corrode brass and copper fittings.
Step 7: Document and Show Your Work
When the test passes, take a photo of the stable reading and share it with your customer or record it in your service notes. This documentation proves that the propane system is safe and leak-free before and after your repair.
At NRVTA, we teach technicians to perform this test twice:
- Once before beginning any propane-related work.
- Once again after repairs are complete.
That second test confirms your repair maintained the integrity of the propane system.
Final Thoughts
A propane leak test isn’t just another task—it’s a critical safety procedure that protects you, your RV, and everyone around you. The time pressure drop test gives you confidence that your system is secure and working as it should.
And if you want to learn how to perform these tests professionally—or even start your own mobile RV repair business—consider training with us at the National RV Training Academy. You’ll get the hands-on experience, certifications, and confidence to keep RVers safe on the road.