Specifications

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The Smart Choice for Energy Efficiency
Th
he Smart Choice for Energ
h. Option to reset unit at thermostat or disconnect.
i. Automatic intelligent reset. Unit shall automatically reset the unit 5 minutes after trip if the fault has cleared. If a fault occurs
3 times sequentially without thermostat meeting temperature, then lockout requiring manual reset will occur.
j. Ability to defeat time delays for servicing.
k. Light emitting diode (LED) on circuit board to indicate high pressure, low pressure, low voltage, high voltage, low water/air
temperature cut-out, condensate overfl ow, and control voltage status.
l. The low-pressure switch shall not be monitored for the fi rst 120 seconds after a compressor start command to prevent
nuisance safety trips.
m. 24V output to cycle a motorized water valve or other device with compressor contactor.
n. Unit Performance Sentinel (UPS). The UPS warns when the heat pump is running ineffi ciently.
o. Water coil low temperature sensing (selectable for water or anti-freeze).
p. Air coil low temperature sensing.
NOTE: Units not providing the 8 safety protections of anti-short cycle, low voltage, high voltage, high refrigerant
pressure, low pressure (loss of charge), air coil low temperature cut-out, water coil low temperature cut-out, and
condensate overfl ow protections will not be accepted.
Option: Enhanced solid state control system (DXM)
This control system features two stage control of cooling and two stage control of heating modes for exacting temperature and
dehumidifi cation purposes.
This control system coupled with a multi-stage thermostat will better dehumidify room air by automatically running the heat
pump’s fan at lower speed on the fi rst stage of cooling thereby implementing low sensible heat ratio cooling. On the need for
higher cooling performance the system will activate the second stage of cooling and automatically switch the fan to the higher
fan speed setting. This system may be further enhanced with a humidistat. Units not having automatic low sensible heat
ratio cooling will not be accepted; as an alternate a hot gas reheat coil may be provided with control system for automatic
activation.
Control shall have all of the above mentioned features of the CXM control system along with the following expanded features:
a. Removable thermostat connector.
b. Night setback control.
c. Random start on return from night setback.
d. Minimized reversing valve operation (Unit control logic shall only switch the reversing valve when cooling is demanded for
the fi rst time. The reversing valve shall be held in this position until the fi rst call for heating, ensuring quiet operation and
increased valve life.).
e. Override temperature control with 2-hour (adjustable) timer for room occupant to override setback temperature at
the thermostat.
f. Dry contact night setback output for digital night setback thermostats.
g. Ability to work with heat pump or heat/cool (Y, W) type thermostats.
h. Ability to work with heat pump thermostats using O or B reversing valve control.
i. Emergency shutdown contacts.
j. Boilerless system heat control at low loop water temperature.
k. Ability to allow up to 3 units to be controlled by one thermostat.
l. Relay to operate an external damper.
m. Ability to automatically change fan speed from multistage thermostat.
n. Relay to start system pump.
o. 75 VA control transformer. Control transformer shall have load side short circuit and overload protection via a built in
circuit breaker.
Remote Service Sentinel (CXM/DXM):
Solid state control system shall communicate with thermostat to display (at the thermostat) the unit status, fault status, and
specifi c fault condition, as well as retrieve previously stored fault that caused unit shutdown. The Remote Service Sentinel allows
building maintenance personnel or service personnel to diagnose unit from the wall thermostat. The control board shall provide
a signal to the thermostat fault light, indicating a lockout. Upon cycling the G (fan) input 3 times within a 60 second time period,
the fault light shall display the specifi c code as indicated by a sequence of fl ashes. A detailed fl ashing code shall be provided