I purchased a house recently that has some spring-powered countdown timers that turn a heat recovery ventilator on.
I was hoping the Maestro MA-T530G would be able to replace those countdown timers (the springs are getting weak, and the units old and brittle) but apparently the HRV lines have too low a wattage pull. The T530G lights flash on and off rather raplidly when installed, and I can hear the electric motor for the HRV turn on and off with every flash.
I do know the HRV switch is 24V. I do not know the exact wattage that runs through the wires, when active.