1993 Sundance I Direct Vent. I did a long over do cleaning.Almost a coffee can amount of soot "clunkers" under burner. Removed logs,some badly sooted areas. Cleaned all & glass put back into service. Noticed logs sooting soon after,Did not have diagram for proper log placement.(have since found) Decided to do a Combustion test,have never done one on fireplace..,14.2% 02..,532ppm CO.., 520F Flue..,67% EFF..,186% Excess air..,3.77% CO2 1653 undiluted CO. Did not see any place on Gas Valve to adj,or check gas pressures.Plan on removing burner this time to clean,and put logs back properly. Is it possible for impinging to raise CO levels that hi? Is that hi of stack temp normal? Thanks ahead.