Will this design work???

[Urban Hillbilly]

Ok....
I am new to all of this, but i have slowly been putting my system together. I will keep it brief because this crude diagram pretty much sums it up. I am just wondering if i have compleatly missed something or if this should work. I am using a Franco Belge solid fuels boiler and the existing gas boiler. I mainly wondering if i need a buffer tank or something else major i may have overlooked. The Franko Belge has a aquastat that controls a damper so hopefully that will keep the temperature somewhat under control. The shut offs are so I can isolate the wood boiler if need be. The diagram is attached. Any help would be much appreciated.
Thanks!

 

[sgschwend]

Take a look at this one, just remove the storage tank. I think you will see that the sources are setup in parallel.

https://www.hearth.com/econtent/index.php/forums/viewthread/19086/

 

[Gooserider]

First off, I suspect that they might want you to have an expansion tank on the solid fuel furnace as well as the PRV if you can isolate it from the existing one, even by accident... Either way, unless the current tank is oversized for the existing system, you will need to add some ET capacity to handle the added boiler volume...

Secondly, while I think what you have would work, assuming you shut off that center valve between the tees connecting the wood burner, it doesn't seem to me like the best approach... I don't like running hot water through the unused boiler - doesn't help anything, and just adds to heat loss as it causes air to flow through the unused combustion chamber and up the chimney, taking the heat with it...

Instead, put the wood burner tees on opposite sides of the fossil boiler, so the two boilers are in parallel. Either put a circ with a flow check on each boiler line, or put an NC zone valve on each boiler with one circ on the radiator loop - This way either boiler fires and turns on its circ, or opens it's ZV and sends water to the rads, without flowing through the other boiler...

Gooserider