Microtech ® Iii Controller - Daikin Enfinity Installation And Maintenance Manual

MicroTech III controller
®
DANGER
To avoid electrical shock, personal injury or death, be sure that
field wiring complies with local and national fire, safety, and
electrical codes, and voltage to the system is within the limits
shown in the job-specific drawings and unit electrical data plate(s).
Power supply to unit
making field connections. To avoid electrical shock, personal
injury or death, be sure to rigorously adhere to field wiring
procedures regarding proper lockout and tagout of components.
General use and information
All Microtech III controller inputs must be operated by
dry contacts powered by the control board's power
terminals. No solid state devices (Triacs) may be used
to operate the Microtech III controller inputs. No outside
power source may be used to operate the Microtech III
controller inputs.
The MicroTech III control system includes two
microprocessor-based control boards conveniently
located in the unit control box for easy access through a
removable access panel. The standalone controls are a
hard wired interface and provides all the necessary field
connections. The board can be wired for 24-volt AC output
to the wall thermostat by using terminals R & C. Two sets
of LED annunciators are located on the front of the unit
chassis to allow quick check of the unit operating status.
MicroTech III unit protections & LED
fault status annunciation
Assumes cycle fan operation-not continuous fan
operation:
■ Start-up – The unit will not operate until all the inputs
and safety controls are checked for normal conditions.
■ Cooling mode – On an initial call for stage 1 cooling,
the fan will energize, the pump request will energize,
and the 45 second flow timer will start. When the
compressor minimum off, and random startup timers
are expired, the lead compressor will start the stage
1 cooling settings. If room setpoint conditions are not
satisfied, the lag compressor will start, which is stage
2 cooling settings. When the room setpoint conditions
are satisfied, the lag compressor will shut off first
followed by the lead compressor when all cooling
requests are satisfied. If fan cycling is enabled, the fan
will turn off once room setpoint conditions are satisfied.
■ Waterside economizer – This mode requires the
optional factory-installed waterside economizer. A
hydronic economizer coil, 3-way water valve and
temperature sensor are added to the unit. The
purpose of this mode is to satisfy some or all of
the cooling demand by using the loop water, which
is often reduced to 50°F or less via the cooling
tower to achieve sufficient cooling performance.
IM 1059-12 LARGE VERTICAL WSHP
must be disconnected when
When a call for 1st stage cooling is engaged, with the
entering loop water below the economizer changeover
temperature, the H8 output on the MicroTech III board
is activated to open the motorized valve allowing water
flow to the equipment. The compressor is locked out,
the 3-way water valve opens to allow cool loop water to
flow through the economizer coil. The fan starts after 30
seconds (unless it is already on thru activation of the G
terminal by the thermostat fan switch "on"). On a further
demand for cooling, stage 2; the 1st compressor will
start in the cooling mode and the waterside economizer
will be disabled. On a further demand for cooling the
second compressor will energize. The waterside
economizer mode will not be activated if the entering
water temperature is below 35°F and an alarm (fault)
signal will be generated.
When the room setpoint conditions are satisfied, the
compressor will shut off, the 3-way valve will close and
the fan will either shut off (fan switch "auto") or continue
to run (fan switch "on"). The minimum off timer of 360
seconds starts. If the loop temperature increases above
the changeover temperature, waterside economizer
mode will be suspended and the unit will resume normal
mechanical cooling mode with stage 1 of the thermostat
now starting the compressor.
■ Dehumidification mode – Uses hot gas reheat with a
2-stage thermostat and humidistat for precise humidity
control.
■ Hot gas reheat with temperature control – If the
space temperature setpoint is satisfied, but the
space humidity is above the humidity setpoint, the
dehumidification mode is activated. The fan will
energize, the pump request will energize, the 45
second flow timer will start, the compressor minimum
off, and random startup timers expire, the hot gas
reheat valve opens sending hot gas to the reheat
coil, the lead compressor energizes, and after 180
seconds the lag compressor energizes. Return air
is cooled and reheated to near space temperature.
A call for cooling will close the hot gas reheat valve
and the unit will resume normal cooling operation.
If the space cooling and heating temperature
setpoints are satisfied, but the humidity falls below
the space humidity setpoint, the dehumidification
mode is suspended.
■ Heating mode – On an initial call for heating, the fan
will energize, the pump request will energize, the 45
second flow timer will start. After the flow, compressor
minimum off, and random startup timers are expired, the
lead compressor will start at stage 1 heating settings;
the reversing valve shall energize 5 seconds after the
lead compressor turns on. If room setpoint conditions
are not satisfied, the lag compressor will operate at
stage 2 heating settings. When the room setpoint
conditions are satisfied, the compressor will shut off. If
fan cycling is enabled, the fan will turn off, once room
setpoint conditions are satisfied.
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ontrols
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