3 way Valve Question/Scenario

[fowlerrudi]

Scenario

I want to run warmboard on one loop, and a hot tub on another. The lower the required water temperature, the more effective my storage correct? So if I have 180 degree water in my storage tank I will run this through a 3 way valve to mix the supply with the return to bring the temperature down so it won't warp my floor/be too hot. If I only need 100 degree water and I'm feeding in 180 degree water, I don't think its going to loose enough temperature to get the temps down. Am I right? What is the solution here? I mentioned the hot tub because that loop might require much hotter temperatures when heating it up.

 

[stee6043]

Simple solution - mixing valve. Taco and Watts both provide valves designed to do exactly what you want. I don't think it's typically referred to as a "three way valve". It's either a mixing valve or thermic valve. Very common....

 

[fowlerrudi]

What is the return is 160 and the supply is 180? You mix and you are still no where near 100 - that is what confuses me.

 

[Bricks]

I am just learning here ... The mix is with the return water from the floor not return to boiler. If I understand correctly the pump will need to be on the return side to the boiler so it pull water thru the valve and floor.

 

[fowlerrudi]

I think I know where my brain is thinking wrong....

I assumed the majority of the water in the zone loop would be coming from the boiler/storage, but in reality since the circ is on the return side, it will just suck as much hot water as it needs from the hot boiler/storage side. Just enough to keep the zone loop at 100 degrees, or whatever you want it to be at.

I assumed the supply would always be running wide open when in reality it is not. I think.....

 

[stee6043]

Perhaps a diagram of what you're doing would help.

A mixing valve mixes hot supply and cold return so that your zone-supply temp is whatever you set the valve at (100 degrees for example). Your pump will keep on pumping but less hot supply water will be used the hotter it is. More mixing occurs to make sure your zone is only seeing 100 degrees.

I think you're second statement is getting closer. Yes, pump on return side and you will only use as much boiler supply as is required....

 

[fowlerrudi]

I've got my head wrapped around it now. It doesn't matter if my water/glycol is 250 degrees - I can still bring it down to 100 by mixing just a little bit of it. Got it. Time for another post about multilayered storage from Froling..... Thanks for the help folks!

 

[powerspec]

Hey whoa! Water glycol at 250 F? Are you really doing that?

 

[fowlerrudi]

No, I was just pretending - just pretending. 212 and she boils right? Then you get steam and a free bomb. On here: (broken link removed to http://www.woodboilers.com/product-detail.aspx?id=58)
They say "With a 450 F maximum operating temperature, there is no need to worry about over-heating." What they heck are they heating?