Performed heating maintenance on a Lennox 93% efficient single stage natural gas furnace Cleared condensate lines of PVC shavings Condensate trap for the furnace is clear Removed burner box cover to gain access to the flame sensor and inspect burners Burners are in good shape Removed flame sensor and cleaned Reinstalled sensor and cover Blower wheel in OK condition Replaced 16x25x1 filter with customer-supplied one No visible signs of water leaks inside or around the furnace Run tested furnace Adjusted gas pressure to 3.5"wc with reference to the sealed burner box No adjustment required to blower speed Temperature rise leveled off at 53⁰, spec is 40-70⁰ Furnace is in good shape, operating within factory specifications at this time No concerns found on today's visit