Changing to unpressurized primary question

[Rugar]

My past Eko boiler (pressurized) was plumbed to gas furnace return with close spaced tees and worked great . Now have unpressurized Heatmaster G100 and would have to make a third loop with a third circulator to use the past connection. That's circulator at wood furnace then one in small loop to move heat from flat plate into system and then one to circulate heating loops. Other option is to tear out old supply or return manifold and plumb flat plate directly in. My problem is space is limited . The easiest would be to connect to supply line immediately out of gas boiler and back in just ahead of load loops. The pressurized system with gas boiler has one circulator to run everything for house that pumpes into boiler .

Guess my main question would be is it just wrong to plumb flat plate directly into supply line going out of gas boiler .

 

[Rugar]

This is supply side . Three 3/4 loops to heat loads .The white pex Al pex was old EKO lines going to return on back .

 

[Rugar]

This is return side. 1 1/4 on wall is return from loops. The two inch close tees are the old Eko supply and return. Then there is circulator into back of gas boiler

 

[TCaldwell]

Hope others chime in, I don’t see anything wrong with piping the flat plate into the gas boiler, I’d think you would need enough flow so the boiler wouldn’t short cycle.

 

[maple1]

I don't think I would plumb a flat plate on the supply line coming out of the gas boiler. The gas would likely cycle since it would see cool return water entering. Then the flat plate would have hot gas boiler water entering and not transfer much if any heat into the system. Unless, that is, the gas boiler gets de-activated somehow so it won't fire when the wood fired side is hot.

Just plumbing the flat plate into the gas/system return line where your Ts are is what would be most straightforward - but if I read right, that isn't straightforward here due to severe space limitations? In that case maybe adding a third circ & short loop to connect the flat plate to your close Ts would be the easiest? If it was mine, and it was spring time, I would likely do some semi-major replumbing. But me & this time of year & a project like that would leave me with a cold house for a while.

 

[Rugar]

Great point on the gas boiler sensing cool water and turning on. That answers part of my problem. I will attempt to fit things in in return or add third loop.

Thank you maple 1