Would this work for storage??

[jrod770]

I'm planning on installing boiler and storage in boiler room attached to garage. What do you think about a tank like this for storage?
(broken link removed to http://columbus.craigslist.org/grd/4178250889.html)

 

[kuribo]

plastic tanks and 180F water aren't a good combo.

 

[altmartion]

I guess you would have to check into the chemicals used in the water. otherwise if it gets insulated well it should be fine. will they hold pressure?

 

[maple1]

Not adviseable.

 

[altmartion]

Not adviseable.

why though?

 

[maple1]

plastic tanks and 180F water aren't a good combo.

This.

 

[arbutus]

why though?

It is a thermoplastic tank, likely polyethylene.
Dip a normal thermoplastic in boiling water and it loses a lot of its strength - by 250 degrees you can bend most thermoplastics by hand.
Sustained 180 degree water temperatures will not only have some loss of strength, but will likely cause the plastic to age/oxidize and become brittle.

There are various high temperature liners and bladders available if you want plastic.

 

[jrod770]

So, IF it does go bad, I put a liner in it and I'm good??

 

[jrod770]

I don't know if they will hold pressure, I just ran across them this AM. Odds are that they will have a big fill hole in them that should have a cap with an o ring. Pressure shouldn't be an issue. What kind of pressure are the boilers running?

 

[maple1]

No.

If it does go bad it might go to pieces.

 

[altmartion]

your best bet is to find the ratings on the tank. there must be something else you can use.

 

[Fred61]

Don't do it. When they fail your problem will be more than a pinhole. Unless it's Xlinked poly like pex, it will disfigure and sort of look like a pretzel.

Not only that polyethylene will allow oxygen to enter your system.

 

[arbutus]

I don't know if they will hold pressure, I just ran across them this AM. Odds are that they will have a big fill hole in them that should have a cap with an o ring. Pressure shouldn't be an issue. What kind of pressure are the boilers running?

Heh. No.
I don't know what exactly the ASME boiler code states for design guidelines, but a typical design pressure is 4x the relief pressure.
Most systems run 15-20 psi, my relief valve is 30 psi, and that tank isn't rated for any pressure.

If it somehow is pressure rated it will have a nameplate and you can see what it was rated and tested at.

 

[altmartion]

Heh. No.
I don't know what exactly the ASME boiler code states for design guidelines, but a typical design pressure is 4x the relief pressure.
Most systems run 15-20 psi, my relief valve is 30 psi, and that tank isn't rated for any pressure.

If it somehow is pressure rated it will have a nameplate and you can see what it was rated and tested at.

a common misconception. actually most average homes only need 4-5 lbs. and that is just enough to help the pump.

 

[Clarkbug]

a common misconception. actually most average homes only need 4-5 lbs. and that is just enough to help the pump.

There is a difference between "need" and "will operate". Just filling the system on a two story house will generate 5 PSI (2.31 ft of head = 1 PSI). So while you dont need to run a system at very high pressures, just the static water column can create quite a bit. You are right, some pressure helps avoid cavitation and also to bleed air from the system.

But I dont think anyone here is going to recommend a plastic tank of that sort for hot water storage, regardless of if its pressurized or open.

 

[Floydian]

a common misconception. actually most average homes only need 4-5 lbs. and that is just enough to help the pump

For a closed/pressurized system most heating pros recommend a minimum of 3 to 4 psi at the highest point of the system. If you have a water column height of 20 ft(typical for two stories and a basement) to the highest point that equals 8.66 psi. Now add your 3 to 4 psi and you have about 12 psi which happens to be the precharged pressure of most expansion tanks. Imagine that

But I dont think anyone here is going to recommend a plastic tank of that sort for hot water storage, regardless of if its pressurized or open.

Yeah I wouldn't recommend it for an open system. For closed/pressurized a plastic tank would just be ridiculous. I understand trying to save some bucks but going cheap and hydronics just don't get along well.

Noah

 

[Lapeer20m]

polyethylene tanks, which appears to be what you linked to on craigslist, are apparently rated for a max of 140 degrees.

while IBC tote containers are rated for at least 240 degrees and are typically 275 gallons. They are too big to fit through a standard doorway, and i've yet to find anyone who actually uses them for thermal storage. However, they are inexpensive and available almost anywhere.

It would be best to have the tote in a location near a drain just to be safe. Unless someone talks me out of it, i will likely use some of these for thermal storage in the future.

 

[Fred61]

Polypropylene is rated for a much higher temperature than polyethylene and is more durable.

 

[heaterman]

No plastic tank should ever be used in a pressurized system. Period.

Unpressurized........meh...
maybe if you used it with a coil or two of copper tube in it that was actually connected to your system.

If you could find one made of plastic that was impermeable to oxygen and would remain stable at 180-190* then yes, maybe, if it was unpressurized