Help setting up variable speed injection mixing

I would use the settings for a 007 and you’ll be close enough, unless you can dial it in with a flow meter.
You should use isolation valves on the injection circ.
Whatever you have between the two manifolds is wrong. It’s only going to see flow from one manifold.
How are you controlling the injection circ? With the right control you’ll be able to monitor the performance of the injection circ. IOW if you see it ramp up high and stop, quickly short cycling your flow/speed is too high. If your circ is running full speed, and your temp sensor shows temperature dropping, not enough flow/speed.

You don't need the separator in that location, and it's only seeing return water from one manifold. You'd want it in the boiler loop after the water feed.
You want to balance the flow on the injection loop circ to account for total btu's needed in both manifolds. You really want enough flow/heat transfer to keep up with the manifold requirements on design day. The control pretty much will come on/off/ramp up and down, based on the connected temperature sensor strapped to the pipe.
You use the valves on each manifold loop to balance the flow/btu's for each loop.

you will need to run the boiler/Indirect circ for the injection to work.

when the tank is hot and boiler turned off you will be circulating hot water through an unfired boiler aka a cooling tower

It’s not a very fuel efficient operating condition

You need to do some math to properly set up the injection flow rate The boiler operating temperature, injection temperature determines injection flow rate

I doubt you will maintain the indirect at 180? But you need at least 130 return to the boiler, so 150- 160?

You will need a thermostatic valve on the dhw if the tank is maintained that hot

The boiler can be run either way. Generally a cold start saves fuel but can cause condensation issues with some setups. Since you have the injection setup, this should not be an issue.

Your thermoset goes to the Tekmar, the Tkemar TT wires to your boiler. If there is call for heat, the boiler is turned on and it will run till it hits is upper limit. If things are set up properly, it won't cycle too much off the upper limit.

If I remember correctly, your boiler is 80k and your floor heat is 40k, that means you want the primary pump at 8gpm and the floor heat pump about the same (20f delta on boiler, 10F delta on floor heat). Without a flow meter, the mix set will have to be a guess. Maybe start with fully open and slowly close it if temperature control on the injection loop is not good.

I would add an air bleeder on the high point of both loops. Can be just a T with small valve/auto vent or one of the cheap air seps. This will significantly simplify getting the air out of the system especially the floor heat loop.

The dirtmag would have been better on the boiler loop as that will be the source of steel. It can work where you put it as well if you are worried about dirt in the floor heat loop, but I would move it on the return to the pump so both loops flow through it.

As I see it you have the boiler piped in series with the indirect, correct?

So that tank needs to be maintained at a temperature to provide the injection mix.

Use the tekmar example showing the boiler running 130/ 160°

So the tank will reach @ 160°, correct. Protect the DHW from leaving the tank at those temperatures!

Now on a call for heat the boiler pump needs to run, as it supplies the needed temperature across the close tees for injection. There may be times that boiler pump is running but the boiler is off, as the tank is hot enough to supply heat. So some of the tanks heat at maybe 160° is going through the boiler.

The radiant pump also needs to run, so 3 pumps need to be running to get heat.

I see 7 loops of 1/2" pex. Typically we design for 1/2 gpm per loop, so you have a 3.5 gpm required flow with all loops connected. If you close off or zone off 4 loops the gpm requirement is 1.5 gpm. (short cycling will get worse not better if you zone the system)

Plug those numbers into the tekmar formula, looks like a .875 gpm injection flow required.

This example is for a system with 15 gpm system flow, I think you are around 3-4 gpm?

If you have not soldered yet, get rid of the bull head tee on the manifold piping.

This injection formula, from Modern Hydronic Heating is a bit more precise

you have a 40,000 load, boiler at 160? supply radiant at 110, return at 100° (10°∆)

40,000÷ 490 (160-100) 1.3 gpm

Without a load calc and design I'm guessing at the load and required SWT to the radiant

plenty of discussions over the years regarding bullhead tee installation, some steam some hydronic. ME a former hydronics instructor explained it well here.

Caution..... Educational Rant ahead....

Bill, One of John Siegenthalers very first articles had to do with the use of bull head tees in a closed loop circuit.

It causes hydraulic imbalance because the direction of flow, and subsequent pressure drop, which affects flow continually changes. Not good.

Lets say you have 10 GPM going into a bull head tee, with each branch of the tee requiring 5 GPM. As the water starts flowing initial, it seeks the path of least resistance. As more water starts flowing through branch A, the pressure drop in branch B becomes less, and it becomes MORE in branch A, so the flow slows in branch A and increases in branch B, until it's pressure drop increases, then it starts all over again.

Remember, water is wet lazy and stupid, and has a really hard time making up its liquid mind. If you had balance cocks on each branch, you MIGHT be able to somewhat stabilize the flow, but it would be tricky. The code use to disallow the use of bull head tees in hydronic systems, but due to inspector confusion over primary secondary piping, and pumped priority, they abandoned that clause of the code completely 2 code changes ago.

The ideal way is to split flow to two branches by drawing from the run and the bull. This way, the hydraulics "lock in" and flow remains stable, until interrupted by a zone control device. I've actually felt the back and forth surging associated with bull head tees using the OHHhhh AHHHhhh method. If you had flow meters in each branch you'd be able to physically see it.

the 519 is my favorite stat for slabs, if you don’t want WiFi

The tekmar website has all sorts of info on the how and whys of their controls

Ideally you would have a sensor well poured into the slab to best apply the slab sensor function

The pwm is a good feature for slabs especially if you don’t have ODR capability

It takes the stat beyond a basic on/ off switch

With ECM circulators and the tekmar controller you might get a power conditioner, UPS, to protect all the microprocessors