I received a call from a client explaining that their gas water heater kept going out. Simple enough, I figured. Probably a thermocouple or maybe a dirty burner assembly—nothing I hadn’t seen a hundred times before.
So, I grabbed my tools, hopped in the truck, and headed over. When I arrived, the homeowner showed me how it would light for a minute, then go out. Sounded pretty standard. I ran through the usual suspects: checked the pilot light, tested the thermocouple, examined the gas valve, and even gave the burner a once-over. Everything was checking out fine. That’s when I knew something wasn’t adding up.
I wish I could say I then checked the water heater’s internal exhaust flue, but I didn’t. Instead, I tried installing a new burner assembly, thinking that the safety limit was broken. After I reconnected everything, I fired it up, and to my dismay, the heater shut off a short while after ignition. Perplexed, I started thoroughly inspecting the exhaust flue with my camera. Nothing. Finally, I tried tugging on the exhaust baffle inside the water heater’s internal flue, and it was lodged tight. This is out of the ordinary. The baffle should sit in the water heater loosely, and can even be pulled out of the top if necessary.
I dismantled the vent pipe from the top of the water heater and, to my shock, discovered that the internal exhaust flue inside the water heater had completely collapsed in on itself. This wasn’t just a partial obstruction—it was fully caved in, blocking exhaust gases from escaping. I’d never seen such a failure in my 10 years in the trade.
That collapse explained everything. The heater would light, start producing heat, but then exhaust gases would back up, triggering the safety mechanisms and extinguishing the flame. It was rare—especially since the water heater was just 3 years old. Thankfully, Rheem covered the failure with a new unit.
I’ll never forget that job. Very odd. But at the end of the day, the client had a working water heater, and I had a story to tell.
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