Header & Zone Valve Orientation

dcwittlo

Is there any reason that a low loss header can't be vertically oriented with the zone valves on horizontal legs? Like this schematic:

I am running out of room on my backboard.

Jamie Hall

So long as the zone valves themselves are oriented correctly, the orientation of the header is not relevant.

hot_rod

No problem. Several boiler manufacturers put the LLH right on the boiler itself, Triangle tube for example.

I've done the same with Lochinvar

boilers as a prototype.

Screenshot 2024-08-19 at 4.24.23 PM.png

EBEBRATT-Ed

The Caleffi in the drawing is the LLH. The piping to the right is just the hot water loops. Hot water can go up, down or horizontal if fact any direction as long as you allow for draining and venting. Of course, you have to respect the mounting positions of any individual locations.

dcwittlo

Thanks for everyone's input. Sometimes there are small "gotchas" that are not obvious. I have read the mfr.s instruction sheets for the zone valves so I know to respect their orientation limits. If I choose to change the orientation I will also allow for draining and venting.

hot_rod

there needs to be a circ on or in the boiler?

I would tie the boiler as a parallel loop not with closely spaced tees

The way you have it piped will require two circs to tun, also temperature blending in the close tees

One purge valve at the sep return is all you need, open one zone valve at a time to purge

dcwittlo

Hot_Rod:

Yes, the boiler (Weil-Mclane Eco Tec 110-H) has a built in circulator (Taco 0015e) on the return side (pumping into the "high flow resistance" Mod-Con boiler).

I am not clear about "tie the boiler as a parallel loop not with closely spaced tees." Did you mean in parallel to the IDHW loop? In my drawing (above) the closely spaced tees are for the IDHW loop. I was aware of the blending issue but it seems like most people make the IDHW to be a Priority Zone so that the Central Heat (or System?) circ is not running at the same time as the IDHW circ. Are you saying that a change in piping could save me the cost of one circulator?

Here is a different schematic. Is this closer to what you meant by "tie the boiler as a parallel loop not with closely spaced tees?"

HomerJSmith

I prefer balancing valves on the cold water return and also like check valves to prevent ghost flows.

hot_rod

https://forum.heatinghelp.com/discussion/comment/1808441#Comment_1808441

correct, tie the boiler to the IDWH as a parallel loop as the second drawing. So when the indirect calls, just its own pump needs to run.

With the closely spaced tees, you would need to run the boiler pump and indirect pump.

Check the control logic, generally the boiler pump turns off and it ramps to 180 when the indirect calls.

It may give you DHW options, depending on which piping you choose.

dcwittlo

I am still confused so I drew a third schematic with the flow paths labelled. I think the problem is that the boiler circulator is inside the boiler and I can only insert the return side tee at the input to the boiler circulator (as opposed to the output of the boiler circ). When the IDHW circ is ON the flow path would be from "A" to "C" and "E" to "C" as well. Also, there would be flow from "D" to "B" and "D" to "F" as well. This would result in backwards flow through the SEP4 and this flow would be in parallel to the flow through the boiler. Some of this could be avoided if there were check valves at points "E" and "F" but, the IDHW circ would be forcing flow through the boiler circulator which would be OFF and would present a high flow resistance. I have also drawn a fourth schematic which would work IF the boiler circ were outside the boiler. It would also require the addition of at least one Check Valve.

Here is the 4th schematic which is possible IF the boiler circulator was outside (separate from) the boiler. If the Boiler circ is relocated as shown then when the IDHW has a priority call flow would be from "A" to "C" and back to the boiler through "D" to "B". Reverse flow thru the SEP4 would be prevented by the integrated check valves in the circulators (or else the check valves would have to be added. As long as the IDHW circulator has priority (Flow arrows labelled "1") and turns OFF the boiler circ, everything would work OK. Unfortunately, I cannot move the internal boiler circ to be external as shown in this 4th schematic (unless I "hack" the Weil-Mclane ECO Tec 110-H).

Would you agree or did I misunderstand you?

Also, here are the schematics provided by Weil-Mclane. The first is from the ECO Tec 110-H Boiler manual, The second is from the AquaPlus IDHW manual.

hot_rod

yes, the pump within the boiler will be a deal breaker. And some models of Weil had a p/s header built in that you could option out by closing valves in the boiler

Better stick with the close tees

dcwittlo

Thanks, Bob.

One more question for the community - I know that the Expansion tank needs to be on the input (suction) side of the circulator. But due to space constraints, I may not be able to locate it lower (vertically) than the return side of the SEP4. Is it OK to have some 1/2" piping going vertically from the return side to a point higher up the wall? If so, does it need an extra Automatic Air Vent?

hot_rod

mount it anywhere it fits, the connection near the sep on either of the bottom return piping

1/2” pex or copper works