Commercial heating repair. Back unit heater is off when you turn it on it makes noise. Found unit heater with a bent fan blade try to straighten it so it would work until new blade and motor comes in with support bracket. When I put back together fan has a wobble to it, it is heating but after 5 minutes the fan shuts down on thermal overload and then the heater locks out on high limit. I left power disconnected so this heater won’t work until new parts come in. Also look at unit heater #7 in building #4 not heating when I turned up thermostat unit came on no lock out codes. I took burner assembly apart and cleaned flame sensor and sparker Armstrong unit heater