www.DaikinApplied.com 45
IM 830-6
9. Outdoor Air/Return Air Damper Actuator (A1):
Proportional, direct-coupled actuator that spring returns
the outdoor air damper to the closed position upon a loss
of power.
10. Face and Bypass Damper Actuator (A2):
Proportional,
direct-coupled actuator that is non-spring returned (Model
AHF and AHB only).
11. Hydronic Coil Low Air Temperature Limit (T6
freezestat):
Factory installed on all units with hydronic
(water) coils. The T6 freezestat cuts out at 38°F (+/- 3°F)
and automatically resets at 45°F (+/- 3°F).
12. Low Refrigerant Temperature Sensor (ICT):
The ICT
sensor is provided on all units with a direct expansion (DX)
cooling coil. It is located on the right hand side of the coil
“u-bend”.
13. Room Temperature Sensor (RAT):
The unit mounted
sensor is located in the sampling chamber (front, center
section) where room air is continuously drawn through
for prompt response to temperature changes in the room.
A Remote Wall Mounted Temperature Sensor is also
available for remote room temperature sensing. (Optional
accessory).
14. Discharge Air Temperature Sensor (DAT):
The sensor
is located at the right end and inside the discharge air
plenum to sense discharge air temperatures.
15. Outdoor Air Temperature Sensor (OAT):
The sensor
is located in the outdoor air section of the unit before the
outdoor air damper. With network applications, the unit
mounted sensor can be overridden by a remote sensor
through the network.
16. Outdoor Air Humidity Sensor (OH) (optional):
Unit
mounted humidity sensor for units using Expanded
outdoor enthalpy economizer or Leading Edge indoor/
outdoor, true enthalpy comparison economizer. The
sensor is located in the outdoor air section of the unit
before the outdoor air damper. With network applications,
the unit mounted sensor can be overridden by a remote
sensor through the network.
17. Room Humidity Sensor (IH) (optional):
Unit mounted
humidity sensor for units capable of passive or active
dehumidification or with units using Leading Edge indoor/
outdoor, true enthalpy comparison economizer. The
sensor is located in the sampling chamber (front, center
panel) where room air is continuously drawn through
for fast response to humidity changes in the room. With
network applications, the unit mounted sensor can be
overridden by a remote sensor through the network.
18. CO2 Sensor (CO2) (optional):
Unit mounted, single
beam absorption infrared gas sensor with a sensing range
of 0 – 2000 ppm and voltage output of 0 to 10 VDC (100
ohm output impedance). The Pitot Tube sensing device
is located in the unit ventilator’s return air stream. The
optional CO2 sensor is used with the UVC’s Demand
Control Ventilation feature to vary the amount of outside
air based on actual room occupancy. With network
applications, the unit mounted sensor can be overridden
by a remote sensor through the network.
19. Control Valve(s) (not shown):
Optional accessory
valve(s) may be either 2 position “End of Cycle” (AHF and
AHB models) or modulating (AHV and AHR models), to
control the quantity of water through the coil. Available in
2-way or 3-way configurations. Spring return actuators
are required for all hot water and steam heating valves.
All heating valves are Normally Open (NO) and all cooling
valves Normally Closed (NC). (See piping/valve section)
20. Water In Temperature Sensor (OCT) (not shown):
The
water in temperature sensor is factory wired on 2-pipe
CW/HW units only. The sensor must be field installed
and insulated (by others) on the supply connection of
the hydronic coil. The sensor must be located on the
supply connection where there is continuous water flow.
It is located on the same side as the coil connections.
The sensor measures the entering water temperature
to determine if the temperature is acceptable for either
heating or cooling based on the unit’s operating state.
(See piping section)
Figure 81: MicroTech Control Board
Note: If Installing Communication Module, refer to the
installation instructions specific to that Communication
Module.
Economizer Control Capabilities
Basic
– Compares the inside and outside air temperatures
using item 13 (Room Temperature Sensor) and item 15
(Outdoor Air Temperature Sensor) to determine if outdoor air
can be used for “free”, economizer cooling operation.
Expanded
- Compares the inside and outside air temperatures
using item 13 (Room Temperature Sensor) and item 15
(Outdoor Air Temperature Sensor) and calculates the enthalpy
of the outside air relative humidity using item 16 (Outdoor Air
Humidity Sensor) to determine if outdoor air can be used for
“free”, economizer cooling operation.
Leading Edge
– True enthalpy comparison economizer that
compares the inside and outside air temperatures using item
13 (Room Temperature Sensor) and item 15 (Outdoor Air
Temperature Sensor) and compares the enthalpy of the inside
and outside air relative humidity using item 16 (Outdoor Air
Humidity Sensor) and item 17 (Room Humidity Sensor) to
determine if outdoor air can be used for “free”, economizer
cooling operation.
Economizer for Reheat
Basic
– Uses items 13 (Room Temperature sensor, item 15
(Outdoor Air Temperature Sensor) and item 17 (Room Humidity
Sensor) for active dehumidification (reheat) or to determine if
outdoor air can be used for “free”, economizer cooling operation.
Leading Edge
- Uses items 13 (Room Temperature Sensor),
item 15 (Outdoor Air Temperature Sensor), item 18 (Outdoor
Air Humidity Sensor) and item 17 (Room Humidity Sensor) for
active dehumidification (reheat) or to determine if outdoor air
can be used for “free”, economizer cooling operation.
