Diagnosed with no heat in lobby 1 of 5 RTU systems Trane 2008 Found blower wheel stuck against the plastic housing Blower wheel is seized on the shaft. pulled the full blower assembly to adjust the depth of the motor bracket. Blower wheel is slightly out of balance but running good now System was running and at 68 set to 70 at arrival time today but would not start and was at 63 a couple days ago Remove flame sensor and spark electrodes for cleaning Inspect heat exchanger Inspect air filters. Inspect thermostat and batteries and test run multiple times for heat mode Unfortunately today I could not witness the broke down system. Several items needed attention but the no heat condition could not be positively identified System is running good set to 70 Air filters are very dirty Recommend regular maintenance on all RTU equipment