Preventative maintenance on Lennox SLP98 style gas furnace. Homeowner reported error code 276 (exceeded maximum ignition tries due to failed calibration). Cleared tubing, combustion analysis CO 10 PPM, cleaned flame sensor, amperage check on inducer assembly and blower. Replaced customer supplied MERV 11-16x25x5 air filter. Recommended having warranty repair completed and water heater replacement. See estimate for details. Homeowner currently has heat at time of completion. Lennox M#SLP98UH090XV48C-05, S#5913K01355. Filter size-MERV 11-16x25x5. Humidifier #35 panel. (Customer does own #35 panel). Note-Included in warranty repair is UV bulb. We need a Lennox P/N-Y0390 style bulb. Replacement was incorrect size. Balance for estimates to be collected when services are completed. Collected for maintenance service only today.