16 IM710
Figure 6: Zone Sensor with Tenant Override
Figure 7: Zone Sensor with Tenant Override and
Remote Setpoint Adjustment
Tenant Override (Timed)
The tenant override button provided with the two optional
zone temperature sensor packages can be used to override
unoccupied operation for a programmed time period. This
time period is adjustable between 0 and 5 hours by the Ten-
ant Ovrd = parameter in the Timer Settings menu of the key-
pad/display (default is 2 hours). Except for the fact that it is
temporary, tenant override operation is identical to occupied
operation.
Pressing and releasing the push button switch on the sensor
momentarily shorts zone temperature sensor ZNT1, resetting
and starting the override timer. The unit then starts up and
runs until the override timer times out.
Note: The button must be held in for 1 second but not
more than 30 seconds.
For detailed information on setting the override timer, refer
to the “Auto/Manual Operation” section of the applicable
operation manual (Refer to Table 1 on page 3).
Note: If this tenant override feature is used on a VAV unit,
it may be necessary to signal the VAV boxes that the
unit is operating. It is recommended that the VAV
Box Output be used for this purpose.
External Discharge Air Reset Signal
The discharge air temperature setpoint on DAC units, can be
reset by an external voltage or current signal applied to ana-
log input MCB-AI2. The external reset method can be
selected at the controller keypad. External reset requires a
field supplied reset signal in the range of 0-10 VDC or 0-20
mA wired to terminals 132 and 133 on the field terminal
block (TB2). Refer to the unit wiring diagrams or Figure 13
on page 33 for wiring termination details.
If the external reset option is selected, the controller linearly
resets the cooling and heating discharge air temperature set
points between user-programmed minimum and maximum
values as the field supplied reset signal varies from a mini-
mum to maximum (or maximum to minimum) value.
WALLSTAT
3
4
120
ZNT1 ZONE SENSOR
Shield Wire
OVERRIDE
121
INPUT
GND.
Unit Terminal
Block TB2
WALLSTAT
3
4
120
ZNT1 ZONE SENSOR
132
6
COOLING & HEATING
SETPOINT
OVERRIDE
121
INPUT
GND.
INPUT
Unit Terminal
Block TB2
CAUTION
Ground loop current hazard. Can cause
equipment damage.
The external reset signal must be isolated
from all grounds other than the MicroTech II
controller chassis ground. If it is not, ground
loop currents can damage or cause erratic
operation of the MicroTech II controller. If the
device or system providing the external reset
signal is connected to a ground other than
the MicroTech II controller chassis, it must be
providing an isolated output. If not, the signal
must be conditioned with a signal isolator.
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