I’ll give that a shot tomorrow. It’s a brand new unit that I just fired up this week for the first time after installing a couple of months ago.
The exhaust port is aligned fine so I don’t think it’s that.
Edited to add:
I got curious and just ran out to test again. I had installed a piece of window screen in front of the exhaust prevent mud dauber wasps from coming in and building nests. After removing it and trying to water heater again, it fired right up and stay lit. Turns out the window screen was enough deflection/baffle to choke off the oxygen and lead to a build up of exhaust.
Thanks for the suggestion to check!
