Hot Water Heater possessed by demon

[FifthLabour]

What we have - An Ultra Low NOx Power Vent Bradford-White (is that three strikes?) 50 Gal. Nat. Gas W heater. There is a Laing recirculating hot water pump. House is seven years old in San Francisco.

What happened - Saturday my wife noticed that the ♨️ water heater was making noise (a continuous water-hammer-like sound with a lot of vibrato) Also, there was a stream of hot water flowing from the bottom of the unit to the floor drain. Our pressure relief valve overflow pipe goes direct to the sewer line (code requirement) so that is not the source of.the water flowing out of the heater bottom pan. I mention this because here is where it gets odd. I turned off the water (hot/cold/recirc. [is that actually the recirc. return line?]), the gas, and turned off the recirc. pump and the ♨︎ water heater control panel switch. Later that day my daughter "needed" to take a shower and "could not" go to the Y and my wife wanted to run the dishwasher so I turned it all back on for a bit. As the weekend progressed I mostly left it off while I tried to call plumbers -(no one has a ULN Power-Vent anything in stock, Home Desperate wants only $1099 for a new heater, $3,00o with installation…). So anyway at one point I restarted the heater, reopened all gas and water valves but left the recirculating pump OFF. No vibration. No noise. NO LEAK!

WTF? There is no leak at the cold intake, or at hot egress, or at the pressure relief valve, or anywhere else that is visible. I imagined the tank vessel lining had perforated but that would not heal itself. I’m not sure if this is relevant but there has been a lot of work on our water mains recently, new homes and major remodels with new water service for sprinklers, etc on both sides and elsewhere on the block. I have had to clean faucet aerator screens frequently, I’m not sure if this is a cause or a symptom…

I have a plumber coming (he said it might be good to understand WHY the heater failed in addition to replacing it and suggested an expansion tank might be helpful as well as checking the way the recirculating system is set up.)

I’m not sure that I need to replace the thing at this point, it is not leaking, banging, or vibrating and the exorcist gave us a six month warranty .

Could this leak be something repairable?

I drained it and strained the first few gallons - see photo. Other photo is the faucet aerator from the garge work sink which I cleaned a few days ago.
Thanks

 

[Jadnashua]

The heat trap(s) on the WH or check valve for the recirculation system may have been partially clogged up and chattering. FWIW, it's a water heater, not a hot water heater...if it was already hot, why heat it?!

When they do maintenance on the lines, all sorts of new crud can get in the lines, and whatever is already there can get dislodged when the inrush of water refills them when they are done.

 

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[Dj2]

1. For your next water heater, install a whole house filter and change the filter regularly or when needed. This will stop most of the junk that flows in.
2. Next water heater, flush it annually. Flushing won't help the old WH at this point.
3. From what you are describing, you have a leak in the tank, even though it didn't leak when you put the WH on last time.
4. I'd rather replace the WH sooner than later, to avoid a major leak damage without you even notice.