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Power supply wire sizing
Long power supply wiring runs require selecting the wire gauge appropriately. If
the wire gauge is inadequate the increased resistance and associated voltage drop
may result in insufficient voltage supply to the Thermostat. The recommended wire
gauge guidelines are as follows.
Min. Load: 4VA (all DOs OFF, No Sylk sensor).
If 14-18AWG wire is used for R, C terminal,
Max. Load: 4A, 96VA (all DOs ON).
If 20-22AWG wire is used for R, C terminal
Max. Load: 3A, 72VA (all DOs ON).
If 24-26AWG wire is used for R, C terminal,
Max. Load: 2A, 48VA (all DOs ON).
DO1, DO2, DO3, DIO1, and DIO2 all relay outputs are powered from the external
transformer. The minimum load includes thermostat and analog outputs at full
load (Max. 10V voltage output with 2K ohms load).
Every relay output is N.O. (Normally Open) contacts with a maximum switch rating
of 24VAC @1A (24VA). The allowed maximum load is 96VA, which assumes all 5
relay output loads are powered from the transformer. Actual power requirements-
depend on connected loads.
IMPORTANT
Use an UL Class 2 rated Transformer or a lesser capable transformer.
The 24VAC secondary leads are not interchangeable. Once a lead connects to the
GND terminal, it is the grounded lead. Observe and maintain polarity for subse-
quent connections. The GND terminal provides a reference ground for the circuit
board and communications wiring. Use 18AWG cable for best results.
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Power supply guidelines and requirements
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