My expansion tank hangs vertical from a pipe. It leaks from where the tank connects to the pipe. I can see some pipe dope where it connects. What can I do?

  • Have you checked your water pressure after the hot water heater has run and no faucets were opened to verify that the tank is still functioning properly? – BMitch Mar 24 '14 at 18:06
  • This is on your heating system or your potable water system? I'm suspecting a heating system, in which case you will have to drain the system before proceeding, unless you can get it to stop leaking by tightening it a bit more. While you'd also have to drain your potable water system if it's there, that's less involved in many ways. – Ecnerwal Mar 24 '14 at 20:34

Remove the tank, re-dope the pipe or wrap it in teflon tape, and reconnect the tank. You'll want to shut the water off first as gregmac aptly suggested; ideally there is a shutoff valve on both sides of the tank, otherwise the water in your house will drain out at low pressure. If you only have one, you'll want to relieve the downstream pipes of water through the faucet closest to the tank and then be prepared to catch any excess with a bucket(s).

  • Can I just shut off the water to the tank, or is there something else I have to do? – Bill Mar 24 '14 at 18:40
  • 2
    @Bill It really depends on where you have valves. The end result is you want to make sure that the part you're disassembling is not pressurized. Failure to do so will generally result in anyone who happens to be watching to break into uncontrollable laughter, and you having to change into dry clothes (and learning a hard lesson about shut-off valves). – gregmac Mar 24 '14 at 23:21

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