Performed furnace clean and tune; noticed that the intake PVC was removed from the furnace and when I went to put the pipe back on I noticed a slight gas smell, I sniffed out the gas line and located one leak and did repair said leak, cycled the system on and checked gas pressures, as well as performed a combustion test verifying no CO in the airstream. This system is currently operating normal and heating at 45 degrees at this time. Job complete