Expansion tank mounting (electric)

[k-n]

I'm about to plumb in the hot water heater and checked with my coop. They have backflow at the meter so I'm closed loop. Therefore I'm going to put in an expansion tank. It's a small 18" diameter electric 30 gallon in a TIGHT space so I don't have a lot of room to play. I have seen the following mount in several pictures and I'm assuming this is "OK". I'd use sweated copper to a T that joins the outgoing hot line via PEX that terminates at a 3/4 connector coming out of the wall. Obviously I would connect flex pipe like in the pic. The copper, I assume, would give enough strength for the smaller (2 gal) tank.

 

[Reach4]

Usually you put the tank on the cold side. I expect you had that in mind, but if you did it on the hot, you would need to make sure your tank was OK for hot. What you show works, but you can put the tank farther from the WH too.

You mention PEX. You could not support the tank on PEX. So if you had that in mind, do something else. PEX passing water to/from the WH should not be within 18 inches of the WH connection anyway.

You could mount the tank to a wall, and run PEX or a flex line to that. In that case, since the flow rate is very small, the PEX could be 1/2 inch or any other size.

 

[Sponsor]

 

[k-n]

Ok, I thought it went on the cold side but in this pic it seems to be on the hot side given the cutoff valve on the other side of the tank... That said, pex is in the wall and terminates there to 3/4 connection (no valve). I would be 18" min of metal flex to the hot water side of the tank. I would mount as seen in the pic on copper for strength with a copper T to the flex pipe. Flex pipe to the cutoff valve from the cold inlet coming from the main.

 

[Jadnashua]

ET's don't tend to last as long when installed on the hot side. Some ET's are not spec'ed for use on the hot side. Therefore, it's safer to put it on the cold side.

 

[Terry]

I normally use brass or galvanized fittings to hang the expansion tank. When the expansion tank fills with water, it gets quite heavy.

 

[Master Plumber Mark]

I normally use brass or galvanized fittings to hang the expansion tank. When the expansion tank fills with water, it gets quite heavy.

thats a nice looking installation Terry, I like the brass elbows....

the one thing I do extra is I cut a piece of pvc pipe to size and shim it in ,
sort of like a leg down from the brass arm to the top of the water heater.....

I dont trust that tee or the pipe threads on the nipple to hold the strain of the weight forever but I know the pvc leg will never fail....

I am very glad I dont have to install those stupid earth quake straps here in our state

 

[hj]

Remember EVERYTHING after the BFP is a single system, EVERY expansion tank in the building is also helping yours.

 

[Dj2]

From Mark: "I am very glad I dont have to install those stupid earth quake straps here in our state"

If you live near Kentucky...that place has more earthquakes than the West Coast. Documented fact.

Install straps, whether required or not. Also buckle up.

 

[Master Plumber Mark]

From Mark: "I am very glad I dont have to install those stupid earth quake straps here in our state"

If you live near Kentucky...that place has more earthquakes than the West Coast. Documented fact.

Install straps, whether required or not. Also buckle up.

They are a total pain in the ass to install, I only have done one of them in the last 15 years
they are not required in our state, so its not gonna happen until they say its mandatory...