Performed furnace clean and tune; inspected the exhaust and intake PVC ensuring all connections were secured, removed and cleaned the burners along with the flame sensor, cycled the system on and checked gas pressures noticed 1st stage would not engage even if i jumped 1st stage heat I replaced the gas valve under manufacturer warranty and this fixed the issue, also performed a combustion test verifying no CO in the airstream, and lastly replaced the 16x25x1 filter. Did want to make note the air quality report that I conducted shows we have a substantial amount of particles in the home I am including a quote for an electronic air cleaner to help bring these levels down. This sytem is currently operating normal at this time Job complete