Upon arrival I was told that front unit wasn’t working at all. During diagnostics I found high and low voltage present at unit but NO 24v going to thermostat. Found duct alarm for AHU 1 ringing in mechanical room. Traced duct to find alarm is in exam room 3. Supply alarm is one that is in fault condition but alarm is out of my reach with 8foot ladder. Need 12foot ladder to reach and work on it comfortably. Informed office. Jumped out alarm at unit to let ac come on and to test for additional problems, none found. After speaking with Crystal at the front desk she got approval from supervisor to leave alarm jumped out for now.