Performed start up on new furnace. No gas leaks detected. Combustion analysis was normal. No CO detected in the air. Electrical and venting components are properly installed. High limit passed safety test. Heat rise was 46 degrees. I asked customer about adhusting the flame and he didn’t think the home was heating up quick enough. I found the filter was dirty and clogged. This may have been the issue. Gas pressures were normal. Unit is operating great at this time.