6 zone boiler wiring and piping, Buderus, Honeywell.

ETOPET

Hello All
I have a new install, I would like to share with everyone.
Attached are the wiring diagram and piping layout I made for my new installation.
I hope you can read the text. Main Boiler components are .
Boiler = Buderus G115
Burner = Riello R40 F3
Aqua-Stat = Honeywell L7248
Please comment if you have any suggestions or comments.
I am not a pro, don't get to technical.
thanks

Paul48

There's no advantage to pumping your loop with largest circ depicted. In fact you show the return flow in both directions on your lo-temp circuit. I'd take a look at some manufacturers diagrams for piping that lo-temp out of the mixing valve.

Tinman

You have a boiler loop and you have two system loops but it's not P/S piping. I'm assuming that's what you were shooting for?

Each set of closely spaced tees should consist of the supply and return pipe for that particular system loop. The first loop should be the one with the highest supply water temperature (baseboard).

Ideally, your mixing valve would be a motorized valve capable of changing as conditions change.

The air scoop depicted should be an air separator like Caleffi's or Spirotherm's.

Tinman

And your boiler loop pump should be piped in just after the air separator before the the tees for the system loops.

Tinman

The more I look, the more see.

Tinman

Need check valves, ECM pumps, etc.

Ironman

As Stephen already indicated, a thermostatic mixing valve is the wrong component for a slab: it will cause it to overheat. You need a smart mixing control that uses outdoor reset. Either a smart mixing valve or variable speed injection mixing (preferred). If a smart mixing valve is used, you must be careful to figure its head loss into the design and select the proper circulator.

Go to Tekmar's site and look up their essay on variable speed injection mixing.

Ironman

Some p/s diagrams are attached. In the one showing the details of the closely spaced Tees, yours would exchange the boiler and system loop labeling. The principle works the same whether heat is being injected or extracted.

I'd highly recommend that you get the book from the store on this site.

Zman

Why so complicated?
The cast iron boiler has no minimum flow requirement. You don't need the boiler circ and loop.
Absolutely use a smart mixing valve. It gives you outdoor reset and will prevent boiler condensation.
You need check valve on the circs.
There is no way to purge air from your piping.
Chances are the transformer has too many valves attached. A zone controller would make the wiring much cleaner.

hot_rod

Keep in mind, with a P/S loop as show you have a temperature drop around the loop as the take-offs are in series. The temperature to each setoff tees will change based on which secondaries are calling.

Another option is a hydro-separator which handles 4 or 5 functions, air, dirt, magnetic, hydraulic separation, and provided the same temperature to every "branch" Smart mixing devices could be added to each branch.

There are a number of brands of "link" products also, that serve as both P/S and distribution, eliminating site built P/S. Add mixing devices at the link, or at the distribution point.

Ironman

Zman said:

Why so complicated?
The cast iron boiler has no minimum flow requirement. You don't need the boiler circ and loop.

That's true that the boiler requires no minimum flow. However, because the Buderus can take return water temp as low as 104*, there is an advantage to using p/s series piping: it will result in lower return temps when the radiant floor and the high temp emitters are both calling and that will result in increased efficiency. It also reduces the likelyhood of the smart control hunting if higher temp water is supplied to it.