Can a WX100 or WX80 be used for a hot water expansion tank?

[Anything Plumbing]

We are installing 3- 500gal propane tanks for hot water storage with a Econoburn boiler. I was wondering if I could use a WX100 or WX80 for a expansion tank?

 

[Bob Rohr]

Good question. That's a Well trol tank, but it does carry a 200F temperature listing??

Be sure on the sizing for the tank you chose. Figure 50 or 55 to 200F temperature range for the sizing. Check with Amtrol on that tank, or the correct sizing for a hydronic one. You may manifold several small ones together, be sure to check and adjust the pre-charge.

My B&G;rep sized me a bit tight and if it runs 200F or over I'm at 28 psi. Reliefs do have a safety factor designed in, so the rep tells me. i'd rather not run that close, however.

That is one down side to large pressurized storage, it takes a monster expansion vessel.

hr

 

[Anything Plumbing]

What kind of tank (name brand) would recommend for this application? Model number are nice if you can.
Also I am trying to size for hot water expansion and i would like to make sure I do this right. I have a total water volume of 1700Gal, a average temp of lets say 200F to be safe, atmospheric pressure of sea level (14.7), system pressure cold 12psi, and a safe maximum pressure of 25psi. My calculation comes up with 334.3 gal minimum storage. Does that sound right? cause that is ALOT of $$$ in tanks

 

[heaterman]

What kind of tank (name brand) would recommend for this application? Model number are nice if you can.

The design program I have won't even go up that high. At a system capacity of 1000 gallons it's indicating an expansion tank volume of over 80 gallons so off the cuff I'd say you're looking at something in the range of 120-150 gallon capacity. Standard Well-X-Trol tanks are not rated for hot water and will fail with monotonous regularity if used for that purpose. Your best bet is to get in touch with a supply house, have them do the math and recommend the appropriate tank.

MOS is right. Expansion tank size is one of the major drawbacks of huge pressurized storage.

 

[Anything Plumbing]

Also I am trying to size for hot water expansion and i would like to make sure I do this right. I have a total water volume of 1700Gal, a average temp of lets say 200F to be safe, atmospheric pressure of sea level (14.7), system pressure cold 12psi, and a safe maximum pressure of 25psi. My calculation comes up with 334.3 gal minimum storage. Does that sound right? cause that is ALOT of $$$ in tanks Can you guys check this?? I used the ICC code Equation to get that.

 

[heaterman]

Also I am trying to size for hot water expansion and i would like to make sure I do this right. I have a total water volume of 1700Gal, a average temp of lets say 200F to be safe, atmospheric pressure of sea level (14.7), system pressure cold 12psi, and a safe maximum pressure of 25psi. My calculation comes up with 334.3 gal minimum storage. Does that sound right? cause that is ALOT of $$$ in tanks Can you guys check this?? I used the ICC code Equation to get that.

Given the parameters you have stated you're pretty much on the money according to a B&G;book I have. It calls for 355 gallons. You might better buy another propane tank and precharge it with air to the required static pressure.

One thing you might want to consider is what fill pressure you actually need to raise the system fluid to the highest point in the piping? More often than you think, a system doesn't actually require 12PSIG fill. By lowering the static fill pressure you might be able to reduce the tank one size.

 

[Anything Plumbing]

Thanks, this is the help I was looking for. I'll try lowering my system pressure, thats a very good point. Also I would like to post a drawing of our piping to get your opinions. The extra propane tank just might be our ticket Thanks again.