Blue shield fall service. Replaced electrostatic filter media that homeowner provided, blower motor is ECM, no run capacitor required, hot surface ignitor checked good, cleaned and checked flame sensor, pressure switch checked good, all limits and safeties checked good, manifold pressures are within mfg specs ( low fire 1.4 in wc, high fire 3.5 in wc), inducer motor run load amps are within mfg specs in both high and low speed, air temperature rise was 48 deg, within mfg specs. * Carbon monoxide 0 ppm. System operating normally. * No carbon monoxide detector in house. Highly recommend one be installed.