David
heated roofs automation
The first question that came to mind for this project was to be sure that there was a UL approved product that we could connect the control microcontroller to. There are a number of options. This one is the most flexible. It allows you override the automatic system and turn the heaters off and on from the relay since it has a HOA switch (Hand control on, Off , or Automatic). You
Right now the electrician is providing this switch. In the new scheme you would deliver the product with this relay/switch that mounts to the panel. In addition you would need to have them install a 24volt transformer (like is used to control doorbells or zone valves) and an outlet for the microcontroller usb cord.
Veris V321 : Enclosed Power Duty Relay, 20A DPDT N.O., Coil: 24VAC/DC, 120VAC, w/2 HOA Switch, Relay Power LED, UL
The Victory 321 DPST power duty enclosed relays combine an industrial-strength relay with installation flexibility...use the nipple mount to attach to any enclosure. One coil input controls the state of two power-rated contacts for simultaneous control of two devices, or both poles of a single-phase load. Each output is enabled with a Hand-Off-Auto switch for local control. The Victory series does not require a dedicated field enclosure, so it is ideal for retrofit projects. Field-selectable high and low voltage coil inputs provide on-site versatility.
