HVAC Procedure and Performance Guide

Test for gas leaks

Training for this procedure can be found in these courses:

                         131 – Oil Heat l  and  161 – Boilers l


All gas leaks must be located using an approved test method.  Applicable safety procedures must be followed.


  1. Collect tools, equipment and materials.
  2. Put on safety and protective equipment and apparel.
  3. Identify section of line to be tested.
  4. Select test procedure:  gas or air pressurization.
  5. Standing pressure test in combination with soap solution test and gas meter reading.
  6. Perform test using procedure selected in Step 4.
  7. Gas pressurization:  Shut gas off at furnace & open gas supply valve at main.
  8. Record gas meter reading.
  9. Apply soap solution to joint and check for bubbles.
  10. Repair leaks and repeat procedure until all leaks are repaired.
  11. Note meter reading when all leaks have been repaired and allow system to stand overnight with gas off at furnace, with main supply open.
  12. Re-check meter reading and determine if gas flow is indicated.
  13. Use high-pressure test to find leaks if gas flow is indicated.
  14. Perform test using procedure selected in preceding step: 
  15. Air pressurization:  Isolate gas line from both furnace and supply ends.
  16. Connect hand-pressurization pump to system.
  17. Pump to elevated pressure, apply soap solution and locate leaks.
  18. Repair leaks.
  19. Re-pressurize line to approximately 10 psi and valve off pump.
  20. Check line in 10 minutes and determine that pressure has not been lost.
  21. Leave equipment in required operating status.
  22. Remove safety and protective equipment and apparel.
  23. Gather tools, equipment and leftover materials, and leave work site clean.