ICM301 Heat Pump Defrost Timer

The ICM301 integrates multiple time and temperature defrost functions onto a low cost, conformally coated, open board package.

Features

• Ultra low cost, time and temperature defrost
• Sensor input for defrost terminate
• Time and temperature terminate
• 10 minute fixed defrost time
• Pin selectable intervals: 30/60/90 minutes
• Test pins reduce test time by 256x
• HOLD input accumulates actual compressor run times
• Simple time and temperature control
• Must have external relays for fan reversing valve and auxiliary heat
• High installed base

Mode of Operation - The ICM301 provides a selectable time interval between defrost cycles. It will allow a 10 minute defrost every 30/60/90 minutes as long as the DFT is closed on the SEN terminal. A HOLD input allows the timer to accumulate time while the compressor is running.

A warm coil causes the DFT to open which will prevent time accumulation or end the defrost period. When the defrost period ends, either by opening the DFT or after the 10 minute defrost period has elapsed, the timer is reset.