Expansion tank failure

[Duetech]

I got up this morning and the house was 55*f. Not a nice start to the day but a start anyway. The boiler was at 200*f and in over heat shut down mode. There was still have a load of wood in the primary chamber. At first I thought I had left the bypass damper open because I for got to cycle the turbulator handle or something. Nope not that. Then I noticed water on the floor and it was dripping from my expansion tank. The tank is/was insulated so I had to change that and found about a 20 ga. wire hole in the upper portion of the tank probably just above the bladder line. I bled the air off the system and removed the tank. Using a wire wheel in my drill I started cleaning the area and found a second hole almost the same size. I use an oxygen scavenger additive in my boiler and the water I got out of the expansion tank was not rusty. Neither was the test I sampled while depressurizing the boiler. Is this just an mfg fluke or is this a likely indicator of some other problem? I appreciate any (useful) feed back you guys my send my way. I say "useful" because "any" is a broad statement and I've had thoughts myself when I've seen it used.

 

[Nofossil]

I've had the air leak out of the bladder on my tank (took 15 years of neglect) but otherwise never had a problem. Maybe cheaper materials and processes these days. All those junk cars that went to Chine had to end up somewhere - maybe your expansion tank was once a Pinto.

 

[Duetech]

nofossil,
It could be a Pinto. I'm sure it wasn't a Vega. I had one of those and I don't think it would have made the trip to China.

 

[WoodNotOil]

So long as the tank was correctly sized and installed correctly, then it must have been a faulty tank. Was there any excess pressure in your system? Did you ever hear a knocking?