Do you have an SMX unit or Sypder controls?

The heaters have a circuit breaker in the panel, if it is on and the thermostat is calling for heat on the heater itself. Be sure the button on the control panel is pushed, if it is a Spyder panel it will turn red. If that control is on then check the main panel for the control buttons, both for voltage coming to it and leaving it. From what you are saying it sounds like the Spyder or SMX unit is not functioning.

Mikee