INSTALLATION CONSIDERATIONS
Power
This control is powered by 24VAC only. It requires 24VAC (Rh and/or Rc and C terminals) of the low−voltage transformer to be connected to it for proper operation. It will not operate without these 2 connections. Rh and Rc are connected via PCB breakout jumper. See Fig. 1. For applications using two 24VAC transformers, one in the indoor unit and one in the outdoor unit, connect the common from each to the C terminal. Connect R from the indoor unit to the Rh terminal. Connect R from the outdoor unit to the Rc terminal. Then, break jumper on the circuit board. The W and HUM signals are taken from the Rh power and the G signal is taken from the Rc power. If Thermidistat Control has been installed in a two−transformer application that is later changed to a single−transformer installation, installer must install a field supplied jumper between Rc and Rh. Depending on the installation, up to 14 wires may be required. Installation as two−piece unit is recommended. Only 2 wires are required for connection between Display Module and Equipment Control Module. These two wires (V+ and Vg) do not provide ordinary 24VAC. They carry a combination of power and communications data that is unique to these products.
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