How to Pressure Test a Heating System?

Pressure testing a heating system helps identify leaks and ensure its integrity. Here's how to do it:

1. Preparation:

   • Ensure the system is isolated from the mains water supply.
   • Completely vent the system, removing all residual air. This is crucial for accurate pressure readings. Air in the system can compress and give false readings.

2. Pressurization:

   • Connect a pressure testing pump to a suitable filling loop or drain valve.
   • Slowly increase the pressure to 6 bar (or the manufacturer's recommended test pressure, if different).

3. Stabilization:

   • Allow a 15-minute stabilization period at 6 bar. This allows the system to settle and any initial expansion to occur.
   • If the pressure drops during this period, repressurize the system back to 6 bar.

4. Testing Period:

   • Maintain the pressure at 6 bar for a further 45 minutes.

5. Leak Detection:

   • After the 45-minute period, carefully observe the pressure gauge.
     • If the pressure holds steady (no significant drop): The system is likely leak-free.
     • If the pressure drops: There's a leak in the system.
   • Visually inspect all pipework, radiators, valves, joints, and the manifold for signs of water leakage. Pay close attention to areas where leaks are common, such as connections and radiator valves.

6. Addressing Leaks:

   • If a leak is found, isolate the affected section of the system.
   • Repair or replace the leaking component.
   • Repeat the pressure test after the repair to ensure the leak has been resolved.

7. Depressurization:

   • After the test, slowly and carefully depressurize the system back to normal operating pressure, following the manufacturer's instructions.

Important Considerations:

• Always consult the heating system manufacturer's instructions for specific pressure testing recommendations.
• Use appropriate personal protective equipment (PPE), such as gloves and eye protection.
• If you are not comfortable performing a pressure test, it is best to hire a qualified heating engineer.
• Over-pressurizing the system can damage components; therefore, never exceed the maximum recommended pressure.