For recent heat pump installation. Rewired thermostat and system per manufacturer’s specifications. Standard heat will default to heat pump. Aux/emergency heat, which is the radiant heat from the boiler, will come on if outside temperature falls below 35 degrees. Added relay to boiler which is powered by air handler transformer. Relay connected to the Taco zone control for kitchen. Yellow tab. Also note common wire is wire nutted together behind thermostat got relay. This brings common back to air handler transformer.
