I have a Taco SR506 relay connectedto a HTP Elite gas boiler. I have 3 zones of heating with hot water baseboard. I have 3 Lennox cooling air handlers in the attic. There are only 5 wires, RH and W go to the Taco relay. It is next to impossible to run an extra C wire through the walls and ceilings. I see there is a SA11 module, however with my system Taco ST506 for heating and Lennox CBX25UVH-024, 2 units and Lennox CBX27UH-030, 1 unit.
how do I wire the SA11? Is it possible to add a 1,000 ohm 1/2 watt resistor in the Taco SR506, and move the W wire to the C terminal in the, Emerson Sensi Touch Smart Thermostat SKU: R5000.45, thermostats?