HVAC Procedure and Performance Guide

Adjust hot-gas bypass

Training for this procedure can be found in these courses:

                         131 – Oil Heat l  and  161 – Boilers l


Hot-gas bypass must be adjusted according to manufacturer’s specifications for specified application. Valve must limit minimum evaporator pressure, compressor cycling or control head pressure.  Applicable safety procedures must be followed.


  1. Review manufacturer’s specifications.
  2. Determine application of valve to be adjusted and manufacturer’s specified conditions to be maintained.
  3. Collect tools, equipment and materials.
  4. Put on safety and protective equipment and apparel.
  5. Remove access cover(s).
  6. Connect refrigeration manifold gage set and/or temperature-measuring instruments to system at locations required for application.
  7. Operate system under conditions that will require gas bypass and adjust valve according to manufacturer’s specifications.
  8. Remove temperature-measuring instruments and manifold gage set.
  9. Replace access cover(s).
  10. Leave equipment in required operating status.
  11. Remove safety and protective equipment and apparel.
  12. Gather tools, equipment and leftover materials, and leave work site clean.