Carrier Heat Pump: Force a defrost cycle by shorting the defrost pins
Force a defrost cycle by shorting the defrost pins on a Carrier heat pump: Starts a defrost by hand. A full defrost only runs with coil at 32 F / 0 C or colder and outdoor air under 50 F / 10 C; otherwise only an abbreviated 30-second defrost. On HK32EA003/008 boards, with the defrost thermostat open you get about 30 s, closed a full cycle.
Applies to: Carrier single-stage communicating heat pump; HK32EA003/008 defrost boards
How to fix force a defrost cycle by shorting the defrost pins: step by step
- Short the two-pin FORCED DEFROST header for 5 seconds, then release
- On HK32EA003/008 boards, short the speed-up pins (J1) with a screwdriver for 5 seconds and release
- On the Infinity single-stage communicating heat pump the same can be commanded from the user interface
If the unit shows an error code, look it up: Carrier Heat Pump codes
Source: Carrier residential A/C and heat pump service manual 24-25, Forced Defrost, p.48; HK32EA003/008 Defrost Control, p.17-18. Written in our own words as a summary; always check the original manual.
General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.