Recently, we had a Navien tankless hot water heater installed in our home. We are satisfied with it's performance on the hot water side of the picture. However, we notice the smell of gas in our backyard often as the heater runs through it's cycles.

We had the contractor back to investigate but they said there was 'nothing wrong' and the the unit normally releases a small amount of gas every time it starts up. In my opinion, the amount of smell and the frequency is unacceptable and I was wondering if my contractor is not doing enough to diagnose and solve this issue. One idea we have is to route the vent much higher up the side of the house so the smell dissipates further prior to hitting ground level. I am also considering getting the gas company out as well.

Thoughts would be greatly appreciated!