ICP Heat Pump: Force a defrost with the SPEEDUP pins
Force a defrost with the SPEEDUP pins on a ICP heat pump: With the unit heating and the defrost thermostat closed, shorting the SPEEDUP pins forces a defrost. Outdoor fan stops and strip heat comes on during defrost.
Applies to: ICP N4H3 heat pumps
How to fix force a defrost with the speedup pins: step by step
- Run the unit in heating with the defrost thermostat closed (or jumper the DFT terminals)
- Short the SPEEDUP pins with a screwdriver until the reversing valve shifts
- Remove the short at once for a brief defrost, or keep it for 2+ seconds to go straight back to heating
If the unit shows an error code, look it up: ICP Heat Pump codes
Models
Source: ICP N4H3 Installation Instructions, Defrost System (defrost control board and testing). 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.