Smart 40 indirect water tank post mortem

Old 04-29-13, 08:09 PM
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Angry Smart 40 indirect water tank post mortem

Triangle Tube Smart 40 indirect water tank, less than 4 years old, fed by a Triangle Tube Prestige 110 boiler.

Power was out for a week following Superstorm Sandy. During that time water leaked out of the air vent on top of the Smart tank and, unbeknownst to me, seeped into the recessed area on top of the tank that holds the aquastat control. That recess filled up with water, submerging the control and also filling the dry well with water. When power was restored days later the aquastat control had seized into the ON position so it was continuously calling for DHW. This went on for at least 3 weeks before I noticed the boiler was running more than usual, cycling on for a few minutes then off for a few minutes, repeatedly with a DHW code.

After consulting with TT we installed a new air vent, aquastat control and sensing bulb after evacuating the water out of the dry well and allowing it to dry.

Operation seemed to return to normal, but after some more time I realized water was seeping out around the plastic shroud covering the top of the tank and dribbling down the side. Called TT again and this time they diagnosed a tank failure.

The replacement tank was provided at no charge under warranty but I had to pay the cost of labor for my installer to swap it which not an insignificant amount. My installer noted the inner tank seemed to have failed because for one thing he wasn't able to drain the tank by pushing air through it.

In review, I don't know if Sandy had anything to do with the original failure or if the timing was just coincidental. For all I know the failure could have even happened before the outage and I just hadn't noticed yet. Anyway, the temperature dropped to the 40 degree range, but not to freezing during the outage. Could such a temperature swing have set these things in motion?

I'm also not sure if the tank failed first leading to the air vent leaking water, or if the air vent failed first leading to a chain of events that caused the tank to overheat and fail.

What I do know is Triangle Tube's design of setting the aquastat and dry well into a recess on top of the tank seems poorly thought out. It's not just at risk from getting submerged by a leaky air vent, but from any of the other piping connections on top of the tank that may happen to leak and flow into that recess. Really dumb, and ultimately expensive for me regardless of the warranty.

Last edited by DanielNJ; 04-29-13 at 08:27 PM.
Old 05-02-13, 05:34 AM
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My guess is that the temperature swing did not cause the problem but everything else will remain a mystery.

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