Unit installation

DCN: 141-00885-16 1/26/06 TZ40 Thermostat Manual 27
TZ40 Power Connection
The TZ40 Control Unit requires 24VAC power from the HVAC system it is controlling. Connect the
24VAC Common (Blue wire/terminal) and 24VAC R (Red wire/terminal) from the HVAC system to the
control unit’s HVAC System terminal block J4’s 24VCom and 24V RH or 24V RC terminals (the RH and
RC terminals are default jumpered together…see below)
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 systems 24VAC R (red wire) to the Control units RH terminal,
and wire the cooling systems 24VAC R to the control units RC terminal. Also wire the cooling systems
24VAC Com to the control units 24VAC Com terminals.