water heater Expansion tank

Has anyone seen one split open if so what would have caused it? I am looking for all reasons not just pressure.
Thank you

Factory defect.

Bad TPRV, allowing the expansion tank to fail rather than the TPRV opening.

Installed on the outlet instead of the inlet.

Wrong pressure in bladder.

Just a few I can think of anyway, but I could be wrong—:smiley:

Along with what Dale said above, expansion tanks also come in various sizes. The size you need depends upon two very important variables. You need to know the capacity in gallons of your hot water heater and the water pressure of your house piping system.

The reason I asked; where I work (real job) I noticed the expansion tank on the restroom water heater had split and been removed. Someone had capped the line and just left it. I pointed it out to the Safety guy and he called the maintenance super who told him that (the only thing the tank is for is extra storage):shock: And the TPR valve was to safely drain the water tank:shock: :shock: I shut off the power to the tank and locked it out.also shut off the water supply and emailed the plant manager about this. I am sure Monday he will have 100 questions. I just wanted to have my gun loaded.</IMG></IMG></IMG>

Michael…here’s a pretty good technical paper on w/h expansion tanks for you reading pleasure:


Thanks for the help guys.

never heard of skydrive before ,hmm

Got the photos now. What do you think?

tank 001.jpg

tank 002.jpg

If it were a lot farther North, I’d say it froze.

This happened in June.

Take a bicycle pump and see if the bladder is still intack. Pump it up a little and take a pressure reading. I bet it is probably blown, but if it is still intack it is probably a manufacture defect. if the bladder doesn’t hold air still, it could be because the bladder failed and built up pressure inside the tank from a bad TPR valve not functioning properly.

You should have the same amount of pressure whether it is on the air side of the bladder or the water side, so I’m not sure what testing the bladder would do. The only reason you need a bladder is due to the fact that the air will get absorbed into the water without one.

I agree that it could have experienced excessive pressure due to a improperly installed or malfunctioning TPR valve.

Most bladder tanks have a schrader valve on them to adjust the air volume/pressure. If the valve leaks, the tank will fill up with water. Same thing can happen is you get a leak in the bladder. The air will eventually absorb into the water. If you have a PRV or check valve on the main line, there is no place for expanding water to go. If you have a stuck TPRV at the water heater, the weakest link in the piping system will break. The real concern here is that you may have a stuck TPRV at the water heater. A bomb waiting to go off!!!

Two things come to mind. 1) Manufacture defect. Tank blew a below rated pressure. 2) There was some nasty pressure (and possible temp) in that tank. Bad TPR or plugged TPR. Either way some testing is in order.

After blowing up the picture, it says 160psi max. Water heater could easily exceed that. Not supposed to, but it could.

The TPR worked fine. The system has backflow valves inline.

I’m not real good just looking at pictures. But perhaps it was overtightened when installed, and the paint came off at the crease. :cool: