old style expansion tank

Patrick_23

I moved my expansion tank yesterday to a more conducive location in my basement (it's now parallel with ceiling joists vs. perpendicular). Had to drain some of the system to accomplish this, run new pipe for supply feed, etc. I had the valve open when I filled the system back up and the tank now appears (by weight estimation) to be about 2/3+ full. Should I have left tank valve closed and THEN opened valve once 'system' was 12-15 psi? What is protocol for draining or moving an old style 15 gallon expansion tank?

Thanks for any info,
patrick

Uni R

expansion tank move

Yes, close the connection to the tank and then "fully" drain the tank. On refilling a system, keep the tank closed, fill the system and then open the tank. If you can bleed any air before opening the tank all the more power to you. One thing to keep in mind when you are draining the tank is that the air is trapped in there and you are creating a partial vaccuum that the water will fill when you reopen the valve to the tank from the heating system. I would drain it with a short hose. When, it seems like the tank has no more water in it and the water stops, I blow a quick shot of air into the hose, and then point it back at the drain, because this forces out a whole load of water. You do not want to ingest this water. I'm starting to think that a nice long straw would work far better... LOL

scrook_2

even an empty tank...

at atmospheric pressure will fill about 50% full at 15psi system pressure and about 45% at 12psi that's why they are so much bigger than a bladder tank, the latter will be virtually empty at 12psi (if the air presure's at 12psi) and about 20% when the system pressure rises to 15psi.

Uni R

old style expansion tank

Very true, which is why it is so important to get it fully drained or it is even less.

Patrick_23

right on about not ingesting this water. I've got some black sludge that evacuated the tank upon my lifting it to the new location. Concrete floor is forever stained I'm afraid--good thing it's in the utility room!

I'll try draining the tank tonight. I've got a drain valve on it so won't be too big an issue. I will post back tomorrow/tonight with an update. Thanks for the quick responses. I got to thinking that I was sending an awful lot of water INTO the tank upon filling the system, so maybe I should CLOSE the valve prior to introducing water. Live and learn, everyday man!