Buderus failure at HW output

JHB

I have an 8 yo Buderus ST 300/1. I noticed a leak at the DHW output. Thinking it was a pipe thread failure, I went to loosen the brass T to replace the tape and the whole thing broke of in my hand. The threads from the tank had corroded to nothing. The pipe, which appears to be cast iron, is sticking out of the back of the tank with no threads left. I removed the insulation from the tank to see if I could replace the feed pipe only to notice it was formed into the tank. It cannot be replaced. The anti-corrode feature has been on the whole time!



Can I re-thread the feed post on the tank? Its a 1" pipe thread. Or, is there some compression fitting I can get to fit over the pipe then connect to the house supply?



Should I consider the tank dead and replace it? its a pricey item!



TIA

JHB

Yup... dead

I emptied the tank and turned on the water feed from the boiler. I see two strong streams of water entering the tank, so the coil has been compromised. The tank is also full of rust streaming down the side of the tank.



I don't run the system with pressure gauges and I think if I did I would have noticed the boiler side running way higher than the 15psi I thought it was at (DW runs at about 50-55psi). I assume that the fresh water entering the tank was being pushed into the boiler side and not the other way around, contaminating the fresh water supply.



I took a photo, for those interested, note the water stream. It's one of two but the other is harder to see.



are Buderus DWH good? Should I look at others during the replacement? Any reason to suspect the boiler at this point.

Rich_49

water quality

Look at the SuperStor units . They are stainless and have a lifetime warranty . These units are as close to bulletproof as it gets .

Plumdog_2

You have no Gauges?

Every boiler needs a temperature and pressure gauge, and a pressure relief valve. The first indicator of a leaking Indirect coil is rising pressure in the boiler, and leaking from the relief valve.