5622 Engineer Drive / Huntington Beach, CA 92649 / Office (800) 228-2966 / Fax (714) 898-6802
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Installation Instructions
Description
MODSTAT / MODS2
Digital Communicating
Zone Thermostat
The ModStat is designed for the ZonexCommander
(Plus), ModCom DDC systems, and the System 2000
GEN II control systems. The ModStat version
thermostat drives medium pressure and heavy duty,
power open/power close dampers for modulating
applications. THE MODS2 version drives low pressure,
power close / spring open dampers for 2-position
systems, which are 2000 CFM or less.
The unique grey display backlight is constantly
illuminated in the Occupied mode. The display backlight
will go out in the Unoccupied mode. If any button is
pressed while the thermostat is in the Unoccupied mode,
the backlight will illuminate for 5 seconds. The backlight
is also illuminated when the thermostat is in the 2-hour
override mode.
Installation
WIRING
All 24 volt and communication wiring connections are
made to terminal blocks on the thermostat sub-base.
The communication terminal block (RX TX / RX TX) is
designed as a junction for two sets of 22 ga solid
copper, twisted pair communications cable. The cable
should be daisy chained from thermostat to thermostat.
See Installation Manual.
1. Install the thermostat sub-base on an interior wall
away from direct sunlight, supply air currents, or any
heat generating source. Mounting screws and
anchors are provided. The sub-base may be
installed on a vertical 2x4 electrical box.
2. Connect the control wires “R” & “C” to the 24v
terminal block. Verify R & C polarity is the same on
each thermostat.
3. On the ModStat, connect the damper control wires
from MC, RC and RO to the actuator terminals. For
MODS2 connect MC and RC to the damper motor.
4. Connect the RX TX communication wires on the
right hand terminal block; there are 2 sets of RX TX
terminals to make the daisy chain wiring easier.
WIRING cont.
NOTE: For ModCom and ZonexCommander (Plus)
systems, when using shielded twisted pair wire (Belden
8450) connect the shield conductors together, as there
are no electrical connections on the thermostat base
terminals. The shield will be landed on the Command
Center on the G or TR2 terminal.
Control Wire Polarity: To insure stable system
communications, you must verify that every ModStat has
the same polarity on terminals “R” and “C”.
Refer to the ZCMAN Installation and Applications
Manual for more detailed wiring instructions.
CONFIGURATION
Addressing
Each thermostat must have a unique address from 1-20.
For System 2000 GEN II, the ModStats are addressed
from 1-10.
1. Press and hold the Menu button until you see the
system mode display on the lower right begin to change
modes; then press and hold the Heat/Cool button with
the Menu button.
2. When the display shows “address,” release the Menu
and Heat/Cool buttons, and press the UP or DN button
until the correct address is displayed in the upper right of
the display.
3. After setting the address, the thermostat will
automatically go back to normal operation; and the set
point temperature will replace the address number just
programmed.
Display Temperature Calibration
Thermostats are calibrated at the factory and should
require no further adjustment. However, the display
space temperature may be field calibrated by the
following procedure:
1. Press and hold the Heat/Cool and Select buttons
together; then press and release the UP button to
increase the display temperature by one degree.
2. To lower the temperature display, press the DN
button once, after pressing the Heat/Cool and Select
buttons. This makes a 1 degree change.
