Each time I would crank up the temperature for the water heater to come on I could smell gas. I placed my meter near the heater exhaust and it confirmed the presence of either carbon monoxide or natural gas. Within a minute it was fine. I also placed a smoke stick near the heater exhaust and it would blow away from the vent at the start up, but again within a minute would start venting properly.
I’m not sure what is causing this??
16 yr old natural gas water heater
No flame rollout on startup
furnace venting is attached below the water heater venting
furnace/water heater exhaust vent is above 2ft of roof surface, with no cause for backdraft
What am I missing?