I can't decide if this is a plumbing question or a heating and air conditioning question

I have Vulcan gas heater, and the fan has stopped, no sign of a burnt out motor, just no fan. You would not think this is important except that the unit is designed to distribute heat through the use of a fan. It isn't very effective as a radiant heater. So who should I call, a plumber and gas fitter, or a heating specialist or an electrician?

Check the thermostat, see if fan runs when fan switch moved to ON. Look at the schematic, could be a capacitor, fan switch, bad motor etc. I'd start with an HVAC person.

Is there a local dealer or Vulcan outlet near you? Got a contact number from the invoice or paperwork? I find it helpful to Google the model numbers and get a manual or contact info, and see what the manufacturer recommends.

A heating and AC tech seems like a good choice.

Call HVAC contractor