The guy from the gas company turned on my gas water heater and held a lit wooden match near where the flue sits on top of the water heater - it blew out. He says it's not getting a correct draft. The flue is 3" diameter and about 4 ft. long, it has an upward pitch of slightly over 1/4" per foot, which in my research is the recommended pitch. (for example here: https://www.howtolookatahouse.com/Blog/Entries/2018/6/what-is-the-minimum-slope-of-a-flue-connector-for-a-gas-furnace-or-water-heater.html#:~:text=%E2%80%9CA%20vent%20connector%20shall%20be,10.7. ) There are two 90-degree elbows, which I also read is the max acceptable.
My house is a 2 story colonial and the water heater is in the basement, so the chimney is pretty tall. I opened the 'hatch' in the side of the chimney in the basement and put a flashlight and mirror in there and the chimney looks straight and clear all the way up to the shiny chimney cap reflecting the sky.
I saw this article here which talks about measuring the draft 60 seconds after lighting the flame: How do I determine if my chimney draft is correct?
My question is: it seems like getting a draft within 60 seconds is unreasonable, there's a lot of air in the system that has to get moving, and unfortunately it's 90 degrees outside, so the buoyancy of the hot air isn't as much as it would be if it were cold outside. What is the correct test to be doing here?
