Filter
Top Products
SmartCommand Thermostat
Installation Manual
28
Control unit connection
The control unit requires 24 VAC power from the HVAC system it is controlling. Connect the 24 VAC
Common (blue wire/terminal) and 24 VAC R (red wire/terminal) from the HVAC system to the control unit’s
HVAC system terminal block J4’s 24V Com and 24V RH (or 24V RC) terminals. The RH and RC terminals
are connected together by JP1 (factory default).
Common or split transformer systems
Most HVAC systems have a common heating and cooling transformer. Connector JP1 is jumpered to common
the RH and RC inputs together for this configuration. If you have a system with separate heating and cooling
transformers, you will need to split the RH and RC jumper by cutting the JP1 jumper.
When wiring split systems, wire the heating system’s 24VAC R (red wire) to the control unit’s RH terminal and
wire the cooling systems 24VAC R (red wire) to the control unit’s RC terminal. Wire the cooling system’s
24VAC Com to the control unit’s 24 VAC Com terminals. Do not connect the heating system’s common wire to
the control unit.