Switched Signal Type Thermostats - TemperZone UNIT CONTROLLER 7 Operation & Installation

Temperzone UC7 Operation & Installation, Air-to-Air Units, Issue 9

3.6. Switched signal type thermostats

Signals from a thermostat that provides switched signals normally connect to the following input
signals:
 COMP
 HEAT (not required for cooling-only installations)
 HIGH – MEDIUM – LOW (required only when the UC7 controls the indoor fan)
If a communicating thermostat is used (TZT-100), or the unit is controlled by a BMS via Modbus over
RS485, or the UC7 is configured as a slave unit, then terminals HEAT, HI, ME, LO, C1, C2 can be left un-
connected.
If the UC7 is configured as a slave unit AND the master unit is controlled by BMS via Modbus over
RS485, or a TZT-100 thermostat is used, then the slave COMP input acts as an input for overload
switches. If no overload switches are to be connected then the COMP input should be made
permanently active with 24V AC or 230V AC.
If the master uses the switched signal type COMP input then each slave unit must also have an
appropriate COMP input signal connected.
Important note for version 3 boards (part number 201 000 403):
UC7 version 3 boards will accept 24V AC or 12V DC control signals on inputs HI, ME, LO, COMP and
HEAT. These boards cannot accept 230V AC control signals!
Important note for version 2 boards (part number 201 000 390):
A new UC7 version 2 board accepts 24V (AC or DC) signals from the thermostat.
It is allowed to connect 230V AC signals to inputs HI, ME, LO, COMP and HEAT. When 230V AC is
applied for the first time to any one of these inputs a small puff of smoke may come from resistors
R61, R56, R50, R68 or R72. This is normal and will occur only once!
(These five resistors are special fusible types, designed for this purpose.)
Once 230V AC has been applied to any of these inputs, they will no longer respond to 24V AC
signals!
Signal level:
24V AC or DC
230V AC
The UC7 provides 12V DC power on terminal "12" that can be used to power a thermostat.
Terminal "G" is the ground return for the 12V DC power.
Terminals "C1" and "C2" must connect to:
24V common
Mains neutral
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