Is your gas booster running but refusing to reach its final pressure?
When a booster stalls before full pressure, the issue is usually not complex, but it always affects efficiency, gas usage, and safety. Most pressure failures come from a few common faults that can be identified with simple, systematic checks.
This guide will break down the five most common reasons a booster cannot reach its final pressure and show you how to diagnose each one safely and correctly.
1. Safety Valve Leak or Loose Connection
A leak anywhere in the system can prevent the booster from reaching its final pressure. Even a very small leak at a fitting or safety valve is enough to stop pressure from building.
How to check
Spray soapy water onto all hose connections and fittings, especially around the safety valve. Watch closely for bubbles. If bubbles form, a leak is present.
How to fix
Fully release all pressure from the system before touching any components. Tighten the loose-fitting and repeat the test. If a seal appears worn or damaged, replace it immediately before operating the booster again.
2. Drive Gas Pressure Is Too Low
If the drive gas pressure is too low, the booster will not have enough force to cycle properly, and pressure buildup will stall.
How to check
Check your drive gas pressure gauge to observe if the pressure is too low for the booster to function. If you are using a high-pressure source, check the regulator; if you are using a workshop compressor, you must confirm it is delivering enough pressure and volume.
How to fix
If the pressure is too low while working with a regulator from a high-pressure source, rise the drive gas pressure. If you are working with a workshop compressor, make sure it is delivering enough pressure and volume.
3. Extraction Cylinder Closed or Empty
If the booster is not receiving enough gas from the extraction cylinder, it will not be able to generate final pressure.
How to check
Confirm that the extraction cylinder valve is fully open. Look at the cylinder pressure to make sure it is not empty or below the level required for boosting.
How to fix
Open the valve completely and repeat the check. If the cylinder is low, ensure you are using a cylinder with enough gas.
4. One-Way Valve Failure
If the internal one-way valve fails, gas can flow backward through the booster. When this happens, pressure cannot be held or increased.
How to test
Disconnect the source cylinder and connect the filling cylinder instead. Open the filling cylinder valve. If pressure comes out through the inlet side of the booster, the one-way valve has failed.
How to fix
If your one-way valve has failed, it will need to be replaced. Because this part operates under high pressure, it is not something that should be repaired on your own. At this point, the safest option is to send the booster to a qualified service station so it can be inspected and restored properly.
5. Booster Not Completing a Full Stroke
If the piston is not completing its full stroke, the booster will not reach its final pressure. This usually points to an issue with the switch-over valve or the pistons.
How to check
Listen carefully while the booster is running. If the piston is cycling too fast or not moving properly, it is likely not completing its full stroke.
How to fix
If the booster is not completing a full stroke, the problem is likely the switch-over valve or pistons. At this stage, it is best to send the booster for repair to a service station so it can be inspected and restored properly.
Get Your Booster Back to Full Performance
When a booster cannot reach its final pressure, the cause is usually one of a few common and manageable issues. By working through these five checks step by step, you can often identify the problem quickly and avoid unnecessary downtime, wasted gas, or unsafe operation.
For a clearer visual explanation, you can also watch Stefan as he walks through troubleshooting these five problems on YouTube:
If none of these checks solves the issue, it may be time for a professional inspection. Some internal components operate under extreme pressure and require proper tools and training to service safely.
Contact us if you need help diagnosing your booster or arranging proper service, and our team at NRC International will be happy to support you!
