HVAC Procedure and Performance Guide
Adjust defrost cycle on heat pump
STANDARD OF PERFORMANCE
Defrost cycle must be adjusted according to manufacturer’s specifications. Defrost cycle must prevent icing of heat-pump outdoor coil during cold weather and must operate only when needed. Applicable safety procedures must be followed.
- Review manufacturer’s specifications.
- Determine type of defrost initiation system (time, temperature, air-flow, or combination) and termination system (time, temperature, or combination).
- Collect tools, equipment and materials.
- Put on safety and protective equipment and apparel.
- Remove access cover(s).
- Determine if all timers are synchronized and if time cycles are correct; adjust to manufacturer’s specifications.
- Measure coil temperatures and/or air-flow and adjust initiation temperature control and/or air-flow switch to manufacturer’s specifications.
- Measure coil temperatures and adjust termination temperature control to manufacturer’s specifications. (Note: If components (timers, switches and thermostats) are not adjustable and defrost cycle is not correct, replace defective components in lieu of making adjustments noted in Steps 6, 7 and 8).
- Replace access cover(s).
- Leave equipment in required operating status.
- Remove safety and protective equipment and apparel.
- Gather tools, equipment and leftover materials, and leave work site clean.