Upon arrival found system in off mode. Homeowner said there was smoke coming out of vents and error codes on tstat. Checked inside unit and found filter clogged. Filter is a Lennox healthy home filter x6675. Checked heat strips with continuity and they were good. Pulled blower and inspected heat strips. Found layers of dust and build up on the 2nd and third set of strips. Recommended replacing heat strips or cleaning. Was getting a communication error for outdoor unit. Found splice in wall at condenser system would need a new Tstat wire to outdoor unit. Checked pressures and amp draws on compressor. Both were good compressor pulling 10.4 out of 24.7. System is on and running, recommended adding a air scrubber uv light so build up doesn’t happen again on heat strips. Emailed repairs over homeowner wants to think about it.