80 gal DHW tank

[huffdawg]

I'm just in the middle of exchanging my 50 gal buderus indirect dhw for an 80 gal eco-king indirect dhw tank. Do you guys think an expansion tank on the dhw side would be a good idea ?

Huff

 

[huffdawg]

 

[velvetfoot]

Maybe not with a well, but I'm no expert. You didn't use one with the 50 gallon tank?
My small gas water heater in my old house came with one, but that was city water. I haven't needed one on my 40 gallon electric heater that's on a well, with no check valve between it and the well tank.

 

[maple1]

I would say shouldn't need one. I don't have one for my 80 gallon electric, on a well with cushion tank. No issues seen.

 

[Bad LP]

Don't have one on the indirect fired DHW side of 120 gallons being fed by almost 750KBTU's

 

[huffdawg]

I didnt have one on my 50 gal. tank either.. On the installation instructions it says to use one . I phoned the wholesaler and he said they don/t use one when they install either.

 

[STIHLY DAN]

It won't hurt it if you do.

 

[velvetfoot]

Don't have one on the indirect fired DHW side of 120 gallons being fed by almost 750KBTU's

750K? How quick does it take to charge the tank...10 minutes?

 

[Fred61]

I have an indirect DHW tank. Not that large but it wouldn't make any difference what size it is in my case. I don't have any check valves on the input line so any excess pressure would backflow into my pressure tank.

 

[jrod770]

The only reason to install one would be if you are on a city water supply with some form of backflow protection at the water meter. If you are on a well, your pressure tank acts as an expansion tank.

 

[huffdawg]

The only reason to install one would be if you are on a city water supply with some form of backflow protection at the water meter. If you are on a well, your pressure tank acts as an expansion tank.

Ya I'm on city water but we are not metered. I just finished up the install, I didn't put in an expansion tank. We'll see how it goes..

 

[Bad LP]

750K? How quick does it take to charge the tank...10 minutes?

From a dead start it takes about 20 mins if the primary loop is hot and the hot water loop pumps are off.

 

[velvetfoot]

My 75k (net) boiler takes about an hour and a half (I'll check it out next time I can) to charge my 120 gallon tank with no loops running. Then again, this is a buffer tank and I let the top of the tank get down to maybe 120 and I heat the tank to maybe 185, averaged over the height of the tank.

Our numbers might not jive, with your 750k for 20 minutes and my 75k for 90 minutes, but eh, it is what it is.

 

[Bad LP]

My 75k (net) boiler takes about an hour and a half (I'll check it out next time I can) to charge my 120 gallon tank with no loops running. Then again, this is a buffer tank and I let the top of the tank get down to maybe 120 and I heat the tank to maybe 185, averaged over the height of the tank.

Our numbers might not jive, with your 750k for 20 minutes and my 75k for 90 minutes, but eh, it is what it is.

I'm talking DHW and satisfied at 140.

 

[huffdawg]

I think mine took around 45 mins @ 170f boiler water temps. start temp for dhw was 52f satisfied @ 160f

 

[STIHLY DAN]

Ya I'm on city water but we are not metered. I just finished up the install, I didn't put in an expansion tank. We'll see how it goes..

You will need one then. That could blow of a lot of water if not. I have seen many a basement ruined this way.

 

[STIHLY DAN]

Sometimes even with a working tank but the city bumped up the pressure. Needed a bigger tank.