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Heat Controller, Inc. DXM2 UNIT CONTROLS Application, Operation, & Maintenance Manual
DXM2 OVERVIEW
The manufacturer’s next generation control board, DXM2,
is the geothermal industry’s fi rst two-way communication.
The DXM2 electronic control is a robust, microprocessor
based heat pump controller that is advanced and feature-
laden for maximum application fl exibility. The DXM2
Control has relay outputs for Compressor, Compressor
Speed, Reversing Valve, Alarm Relay, and 2 confi gurable
relays for Fan, Fan Speed, HWG Pump, and Loop Pump,
and 2 confi gurable accessory relay outputs. For on board
diagnostics, there are 2 LED’s to provide status indication.
There are inputs for safety pressure switches, low
temperature protection thermistors, condensate overfl ow
sensor, DIP switch selection inputs, thermostat inputs, night
setback inputs, and emergency shutdown input. Additional
confi gurable temperature sensor inputs are available that
may be used for hot water, compressor discharge, leaving
air, leaving water, and entering water temperature sensors.
The DXM2 has an RS485 communications port to interface
with a communicating thermostat or other compatible
controls.
DXM2 Controller Part Number:
17B0002N02 DXM2 Control Board
General Operating Parameters
The following are general operating parameters for the
DXM2 Control:
• Operating Environment: -40°F to 176°F and up to 95%
relative humidity, non-condensing.
• Storage Environment: -40°F to 185°F and up to 95%
relative humidity, non-condensing.
Power Requirements
DXM2 only power draw -
• Normally 8 VA draw at 24VAC
• Maximum 12 VA draw at 24VAC. A dedicated 24VAC,
50-60Hz, 1Ph, 40VA transformer minimum is required for
typical WSHP application.
Relay and Connection Contact Ratings
The following relays are mounted on the DXM2 Control:
• Compressor Relay: 40VA at 24VAC
• Compressor Speed Relay: 28VA at 24VAC
• Alarm Relay: 28VA at 24VAC
• Reversing Valve: 28VA at 24VAC
• Accessory Relay 1: 28VA at 24VAC
• Accessory Relay 2: 28VA at 24VAC
• Fan Enable / Loop Pump Relay: 1 HP at 240VAC
• Fan Speed / HWG Pump Relay: 1 HP at 240VAC
• Connection ratings on the DXM2 Control:
• ‘A’ terminal: 20VA at 24VAC. Larger solenoid valve draw
should be controlled with accessory relays.
Grounding
The control board must be grounded from one of the C
terminals.
Basic Control Features
• Single or two–stage compressor control
• Anti-short cycle protection
• High pressure cut-out
• Loss of charge cut-out
• High and low voltage cut-outs
• Water coil low temperature cut-out
• Air coil low temperature cut-out
• Random start
• Status LED and Fault LED
• Reset lockout at unit or disconnect
• Condensate overfl ow sensor
• Intelligent fault retry
• Test Mode
• Multiple blower confi guration options
• Electric heat outputs
• Accessory water valve connection
Advanced Control Features
• Direct control of ECM blower
• Intelligent hot water generator control
• Two accessory relays confi gurable for multiple
applications
• Internal Flow Center output
• Proportional valve output
• Night setback with override capability
• Emergency shutdown capability
• Removable thermostat connector for ease of installation
and service
• Accepts conventional heat pump (Y,O) or heat/cool (Y,W)
thermostat types
• RS–485 port to interface with a communicating
thermostat or other compatible controls
• Boilerless electric heat
• Confi gurable inputs and outputs for advanced functions
DXM2 Electronic Heat Pump Controls
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