Any limit to the number of turns a vent pipe can have? Top of tank was corroded and rusted, I thinking from condensation generated by all these turns.
That’s an induced draft water heater. Probably a condensing type which is intended to produce condensation inside the exhaust vent. Water staining on the outside of the vent and lack of visible primer raises the question of whether all of the joints were properly cemented (looks like one or more joints are leaking). The galvanized nipple on top of the water heater is heavily corroded (possibly not related to the vent) and seems to be at the epicenter of the corrosion on the wh jacket. It looks like someone just recently sweated the joint on the old female adapter (you can see fresh scratch lines from the Emory cloth which are still bright and shiny - probably much newer than the patina on the fitting). Maybe they were just cleaning the schmutz off of it to look a little bit better???
WH looks like it’s probably near the end of life. What is the age of the unit?
Remember, you do not need to diagnose the specific cause. It’s nice when you can do so reliably but don’t put yourself out there on a limb with conjecture if you cannot validate it.
Be sure to articulate what you know to be factually true:
- There are water stains on the vent
- There is corrosion on the top of the unit
- The nipple is corroded at the water supply connection
- If the unit is at or near typical end of life - say so
believe it or not its a 2014
Find a copy of the manufacturer’s installation instructions and see what it says about the vent pipe.