HVAC Procedure and Performance Guide

Adjust compressor start-delay timer

Training for this procedure can be found in these courses:

                         131 – Oil Heat l  and  161 – Boilers l


Start-delay timer (anti-short cycle timer) must be adjusted according to timer manufacturer’s specifications.  Timer must delay compressor restart until system pressures have equalized to allowable restart level.  Applicable safety procedures must be followed.


  1. Review timer manufacturer’s specifications.
  2. Determine start delay time required and if timer is adjustable.
  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 to system.
  7. Locate start-delay timer and connect electrical test equipment.
  8. Start system and bring to stabilized operating condition.
  9. Stop compressor and restart immediately.
  10. Measure time delay between restart signal and actual starting of compressor; monitor system pressure changes.
  11. Set timer to provide specified time delay or provide adequate time delay to allow system pressures to equalize to specified range.  (Note:  If timer is not adjustable and cycle is not correct, timer must be replaced).
  12. Disconnect manifold gage set and electrical test equipment.
  13. Replace access cover(s).
  14. Leave equipment in required operating status.
  15. Remove safety and protective equipment and apparel.
  16. Gather tools, equipment and leftover materials, and leave work site clean.