Radiant Floor Design Critique

with the concrete poured, it's late to ask,
but,
what's your loop lengths, and tube size?

I would move the dirtmag to the secondary before the boiler return tee. That way all the flow will go thru it giving you maximum effectiveness.

I would skip the cast iron air scoop, and use a proper microbubble air separator.

At 60kbtu heat load it's likely you could use a single delta p circulator and zone valves, saving some power.

For you primary secondary arrangement, you need to make sure your headers are big enough to avoid flow interactions.

I think the grundfos pumps come with a check valve they can be field installed into the discharge of the pump. It has the advantage of having a minimal effect on pump performance.

Install the dirt mag on boiler return upstream of the boiler loop circulator is the best location. That way any impurities in the system are captured before they reach the boiler, and associated circ on initial commissioning of system. Also the dirt mag is more efficient in lower flow regions. If set up properly the boiler loop flow rate should be less than system flow rate.

A 4 in 1 hydro sep would clean it up and give you 4 functions in one box.

If you use that schematic, I move the expansion tank to the left of the close tees.

You could use zone valves with one circulator if you have the two manifolds for 2 zones.

> @flyingmeatball said:
> Thanks all for the constructive comments.
>
> @neilc - I have ~2300 ft of 1/2" pex tubing - one manifold has 4 loops at ~180 ft, the other has 8 loops at ~210 ft
>
> @SuperJ - good suggestions all around - 12 actuators was going to cost a lot more than 1 extra grundfos pump, so I went that route. I know I'll pay for it over time in power, but my wife is less likely to scrutinize the electric bill vs. the plumbing supply receipt . Noted on the microbubble - will change that. Can you elaborate on the header comment a bit more? I'm using 1" copper pipe into a 1" manifold, I thought that was going to be plenty big for the system I had...The check valves would have been a good idea, but I'm too lazy to RMA the ones I have/reorder.
>
> @snowmelt @hot rod_7 - good suggestion, and surely the "correct" way to go. I'm going to go with what I've got for the sake of learning/not having to return stuff though. Takes the "fun" out of figuring out what the parts do/how they work.
>
> @Gordy @SuperJ - Two conflicting options on dirtmag location,
> current setup logic: dirtmag is in lowest point of system with the lowest flow - dirt is likely to accumulate here. The boiler circ is indeed upstream of the dirt mag, but if I put the dirt mag first, the circ ends up at the lowest point of the system - install instructions say, " Do not install the pump at the lowest point of the system where dirt and sediment naturally collect."
> Different Option 1: put the dirtmag on boiler return before pump. This results in boiler circ being at lowest point in system - is it better to have the dirt mag first, even if it means putting circ down here?
>
>
>
> Different Option 2: Move dirtmag on secondary upstream of boiler return. This means water will be flowing faster when it hits dirt mag, but everything will flow through it, vs just the water returning to the boiler. This also isn't the lowest point in the system - which is better, the slow water at lowest point, or filtering all of the water?
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>
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> @Zman - I thought there might be some fill/purge scenario where I'd like to have the full secondary loop running without going through a zone. If that would never happen I can remove, but I was trying to be safe rather than sorry. I've seen some versions as well that have pressure bypass valves there - is that not a concern at all for future expansion/troubleshooting?
>
>
> Thanks all for your input - much appreciated!

I like option 2 so all return water from the house has to go thru the separator, just make sure it's sized for the flow rate, if the velocity is too high, or the separator too small, it will be less effective.
A minor change is I would have the air separator on the secondary after the boiler supply tee, it's easier to get the bubbles out of hot water.

Regarding the zone valves I assumed 2 zones not 12, maybe that's an option? You can zone with a 2 way valve in front of the manifold, you don't need to zone every circuit necessarily.

I agree with the others that a hydraulic separator with air, dirt, mag separation would be the nicest option, if you have purchased the parts yet.

Use the combi discal/dirt/mag 5461. A 3in1 devicethat solves the location question

I would get a system sensor installed. Looks like you can handle a temp delta up to 40f, but the system sensor will be required if system flow is greater than boiler flow to keep system at setpoint. You want it that way so the boiler return temp is minimized to maximum condensation/efficiency.

You can use pressure drop or temp delta to confirm flow (I recommend checking both to be safe).

Great I'm glad it worked out, thanks for sharing the ultimate solution.