iWorx® HPU3
505-035, Effective: June 30, 2015
3
© 2015 Taco Electronic Solutions, Inc.
HPU3
The HPU3 heat pump controller is a stand-alone microprocessor-based controller for liquid source heat pump units.
The application includes liquid source heat pump units with two-stage compressor, reversing valve, fan, dehumidifica-
tion (internal and external), humidification, and auxiliary (emergency) heat.
Overview
The HPU3 incorporates digital outputs in the form of triacs for digital fan fan start/stop, two compressor stages, dehu-
midification enable, humidification enable, reheat enable, auxiliary heat enable, and a reversing valve. An analog out-
put for modulated fan control is also provided. Digital inputs are provided to monitor equipment status and high and low
pressure alarms. A two-wire serial interface is provided for the thermostat. Analog inputs are available for optional
space temperature, power transducer, supply air temperature, and supply air humidity.
The controller is based on L
ON
W
ORKS
®
networking technology. The controller can be networked to a higher-level control
system for monitoring and control applications.
Features
• Two stage compressor heating/cooling control
• Reversing valve control
• Auxiliary (Emergency) Heat enable
• Dehumidification with Reheat, both internal and external
• Humidification with SAT monitoring
• Local backup schedule
• Individual temperature setpoints for occupied/unoccupied heat and cool
• L
ON
W
ORKS
interface to building automation systems
• Equipment status input for additional safety interlocks
• High and Low Pressure Alarm inputs
• Thermostat with space temperature, humidity, temperature setpoint adjust, fan override, occupancy override
• Fan control energized on call for heating or cooling
• Automatic heat/cool changeover
• Global unit enable for main plant synchronization
• Remote sensor capabilities
• Automatic configuration with the LCI
• Real Time Clock
• Alarm/Event reporting
PURPOSE OF THIS GUIDE
The
iWorx® HPU3 Application Guide
provides application information for the HPU3 Controller.
The reader should understand basic HVAC concepts, intelligent environmental control automation, and basic L
ON-
W
ORKS
networking and communications. This application manual is written for:
• Users who engineer control logic
• Users who set up hardware configuration
• Users who change hardware or control logic
• Technicians and field engineers
