There is currently not a dedicated pair of 24 VAC terminal blocks on the Caleffi Z-one Relay Control board for auxiliary power, however, constant 24 VAC is available at any of the thermostat terminals R-C. All thermostat R-C terminals on a given control board are powered from the same 24 VAC transformer(s) secondary. Tie into any convenient R-C, but be sure to sum up all the 24 VAC loads, per board, to make sure you do not exceed the total VA rating of the transformer(s).
