2020 MXZ Multi-Zone Tech Manual

Specifications subject to change without notice. 17 Communication Explanation The indoor unit is powered by the S1 and S2 wires. S1 is the same phase as Line 1. S2 is the same phase as L2. S3 is also the same phase as L2 Because the S2 and S3 wires are the same phase and have no voltage potential between them, a digital data signal can be transmited over thosewires. S3 carries the communication signal and S2 is used by the controlboards as a zero reference for the signal. This signal is in the form of 1's and 0's, high and low volts DC. In order for the signal to be read and processed properly by the control boards, the timing between the transmission and reception of those signals must be kept within usable parameters. Anything that delays or interferes with the reception of a signal, or causes a distortion of the signal waveform may cause the signals to be repeated or misinterpreted. Wiring that is too large means the signal must travel a greater distance over the length of the wire. Each step up in wire gauge is 59% larger than the previous size. Wiring with splices will cause signal delays as they pass through the splice and can cause signal distortions leading to miss-interpretation of a signal. If the S2 and/or the S3 wire are routed in a parallel pathway near other power wiring, an RFI, or Radio Frequency Interference can be induced on the signal wires caused by the magnetic field produced by current flow in the adjacent wire. This will cause a distortion in the signal and also cause miss-interpretation of that signal. The three general rules that should be considered to prevent the described communication issues are: 1: Right size wire [14 or 16 AWG] depending on the unit or system 2: No splices in either S1, S2 and S3 wiring 3: Keep the S1, S2 and S3 wiring a minimum of 2 inches from parallel circuits with larger current values Violation of the described wiring rules are known to cause operational problems and should be avoided to insure proper communication takes place Voltage Measurements