Question on hydroponic system routing

[Husky79]

I am wondering if the boiler pump needs to be before the mixer valve? Or can it be after? The way I set up my panel, having the mix valve before the pump is ideal.

I have attached picture of my mock setup, the boiler pump Wil be placed above the zone 2 pump (the one routing to the 4 branch manifold.)

 

[chinboys]

Apologies, but it's called hydronics.

Boiler pump pumps the heated fluid from the boiler through a supply and return loop relative to the boiler.

Your manifolds will have their own pumps from which to draw from the above loop and return to this loop.

Not sure about the mixing valve pump set up other than the cold side of the mixing valve is to be fed by the return side of the manifold or boiler loop where there ought to be 20 degree temp drop. The hot leg is feed from the boiler loop. The mixed water is fed to the manifold.

I would suggest you review the piping diameter and lengths relative to the btu's you wish to deliver and what temperature relative to how long or fast you wish to heat up in. You may also have a water flow contention should both circuits/manifolds call for heat on all of their zones... Larger diameter piping on the boiler loop.
You might be too pumping too much water and at higher pressures than your boiler specs.

 

[TurnipTruck]

Here are some thoughts on pump vs expansion tank locations from Caleffi:





pump vs mixer valve on the low temperature branch:




and some thoughts and a diagram of primary/secondary plumbing including “closely spaced tees”:


You HAVE TO include some sort of hydraulic separation to isolate the varying and often significantly greater flow of the load from the flow through the boiler. The cheapest is “closely spaced tees” on a primary/secondary loop, but powered smart mixer valves are complex and hydraulic separation tanks can be simple but expensive.

 

[fitter30]

What boiler are u using? How many feet of pex, size, number of loops and loops length? Does the pex have a oxygen barrier?