3-way valve and circ pump location

[mpilihp]

Hi again, looking for input on where to place the 3-way valve for return temp control and the circulating pump for the wood boiler. See image.

http://i103.photobucket.com/albums/m132/mjenphil/WoodBoiler/Pump-location.jpg

To me it would make sense to place the pump between the wood boiler and the 3-way mix port so its drawing both hot and cold return water through equally. WHere as in the setup on the right it would be pushing cold water into the valve and possibly not allowing the valve to work properly and inject the needed hot water? Your input is much appreciated.

~ Phil

 

[steam man]

The first drawing is correct for mixing. Alternatively for diverting you could place a 3 way valve at the top of the first drawing to direct flow to the load or back to the wood boiler based on temp. Just be sure the valve you use is approved for its specific location, i.e. mixing and/or diverting. Note in the second drawing there is no way to recirc back around through the wood boiler.

Mike

 

[mpilihp]

THanks Mike thats what I thought, not sure about what your saying in your last sentence, I think the pump would push through the 3-way valve, are you saying that if the MIX port is set to 140 deg and the cold return coming through the pump is at 90, then the valve will be closed on the cold, not allowing any though and expecting the hot to be passed through to the mixed port? If so then I get it.

~ Phil

 

[steam man]

THanks Mike thats what I thought, not sure about what your saying in your last sentence, I think the pump would push through the 3-way valve, are you saying that if the MIX port is set to 140 deg and the cold return coming through the pump is at 90, then the valve will be closed on the cold, not allowing any though and expecting the hot to be passed through to the mixed port? If so then I get it.

~ Phil

In your second drawing the pump is "pushing" through the 3 way valve. It can't be done if there is another input as shown. As I mentioned you can mix or divert. Divert is one in two out and mix is two in one out. The pump is always on the "one" side, pushing for diverting and pulling for mixing. Whatever the temp rating of the 3 way valve will determine what flows out the mixed side. If the temperature is low (below 140) it will just keep recirculating through your wood boiler. No matter which way you pipe it the pump will always be on the wood boiler side of things.