General Use And Information; Operating Modes; Safety Inputs (Hps, Lps, Slts, Cos) - Daikin MicroTech III Installation And Maintenance Manual

General Use and Information

The Microtech III SmartSource unit controller is a water
source heat pump control platform used to control the heat
pump in all modes of operation, including variable speed
fans, two stage compressors, loop pumps, waterside
economizers, hydronic heat, electric heat, two-way valves,
reversing valves, and all components used to control
conditioned space temperature and humidity . By adding
communications cards, (L
on
integration is possible . The controller can be used with
thermostat or sensor control .
All MicroTech III unit controller inputs must be operated by
dry contacts powered by the control board's power terminals
or appropriate Daikin sensors . No solid state devices
(Triacs) may be used to operate MicroTech III unit controller
inputs . No external power sources may be used to operate
MicroTech III . All units must be properly grounded per local
code requirements . See the Installation and Maintenance
bulletin specific to your Water Source Heat Pump.

Operating Modes

The I/O Expansion Module is an expansion of the main
board and provides extra functionality to the MicroTech
III control system .
• The MicroTech III unit controller in combination with
the I/O Expansion Module will be the standard control
system for SmartSource Water Source Heat Pumps .
Adding an I/O Expansion Module (with an interconnect
cable) to the main controller allows:
• Compressor High Capacity On/Off Control
• Variable Speed Fan Control
• Water Side Economizer Control
• Active Hot Gas/Reheat (HGR), or Low Capacity
Dehumidification Options
• Boilerless & Supplemental Auxiliary Heating Options
• The fourth thermostat Heating Stage (W4) Input
• Hydronic Heating Control
The I/O Expansion Module has an independent LED
annunciator to identify operational fault conditions .
The MicroTech III SmartSource unit controller will
manage occupied and unoccupied modes of operation .
■ Occupied Mode – When in the occupied mode, the
unit will be controlled to its occupied setpoint conditions .
The occupancy mode can be established by a BACnet
or L W communication signal, from a room
on orks
sensor equipped with "Occupied/Unoccupied" mode
functions, or a thermostat equipped with an "Occupied/
Unoccupied" mode switch . The occupancy state will be
displayed on sensors equipped with a status LED .
■ Unoccupied Mode – When in the unoccupied mode,
the unit will be controlled to its unoccupied setpoints .
The occupancy state will be displayed on sensors
equipped with a status LED .
www .DaikinApplied .com
W or BACnet) network
orks
A contact closure between terminals U and C on the
MicroTech III SmartSource unit controller will place the
unit into the unoccupied mode for night setback/setup
operation . Thermostat equipped units will be controlled
from Y2, W2, W3, W4 and DH inputs . The fan will cycle
according to a call for cooling, dehumidification or heating.
■ Override Mode – A momentary (4 to 9 seconds) press
of the "Override" button on the thermostat or room
sensor during the unoccupied mode will cause the unit
to operate in the occupied mode for up to two hours,
for after-hours heating, cooling or dehumidification.
"OVERRIDE" will be displayed on sensors equipped
with override button and status LED .
■ "Energy Save" Standby – BACnet or L
units can receive a signal from the Building Automation
System (BAS) to initiate the energy savings mode . This
mode is typically initiated by the BAS with smart grid
technologies to save energy . The savings is driven by
reducing peak electrical demand for the building . Once
initiated, the MicroTech III SmartSource unit controller
will reset its effective setpoint to minimize compressor
operation . "E-SAVE" will be displayed on sensors
equipped with bypass mode annunciation capabilities .
■ Remote Shutdown – When the unit is in the remote
shutdown mode, unit operation is suspended . A contact
closure between terminals E and C on the MicroTech
III SmartSource unit controller will place the unit into
remote shutdown mode .

Safety Inputs (HPS, LPS, SLTS, COS)

The control inputs are High Pressure Switch (HPS),
Low Pressure Switch (LPS), Suction Line Temperature
Sensor (SLTS), Condensate Overflow Sensor (COS).
The control inputs are in normal states during occupied
mode . The state of each control in occupied mode during
normal operation is as follows:
■ High Pressure Switch (HPS) – Normally closed switch
that opens on a high refrigerant pressure condition .
Control will generate a high pressure fault and will
disable the compressor output when the switch is open .
■ Low Pressure Switch (LPS) – Normally closed switch
that opens on a low refrigerant pressure condition .
Control will generate a low pressure fault and will
disable the compressor output when the switch is open .
■ Suction Line Temperature Sensor (SLTS) –
Monitors refrigerant suction line temperature . Control
will generate a low temperature fault when the suction
temperature drops below the cutout setpoint and will
disable the compressor output .
■ Condensate Overflow Sensor (COS) – Senses
condensate level in condensate pan . Control
will generate a condensate overflow fault when
condensate level is too high and will disable the
compressor in the cooling and dehumidification
modes .
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