Heating maintenance Duluth. Completed maintenance on 2 11 year old systems. Both systems heating properly. Ignitors and flame sensors are good. Inducer motors running good. Blowers are clean. Evap coils are very rusted and corroded. Suggest replacing them to avoid leaks in the future. Filters are good. Static pressure is good on both. All safety switches working. Systems would benefit from having UV light systems installed to kill any bacteria or viruses in air that could cause harm to residents. Gas lines on both are not ran properly to avoid sediment getting into gas valve that can cause it to fail. Need to re run gas line to utilize sediment trap.