Vision Piping Schematics

Tom Hughes

The Vision piping schematics don't make sense to me. Why wouldn't you run one primary loop at 140-180 degrees, and have both the Superstor tank and hydronic heating loop on their own secondary pumps decoupled from the primary loop? That way you can serve both loads at the same time and each seconday loop can have whatever temperature it needs. What am i missing?

Unknown

Sounds OK to me

As long as the indirect load added to the rest of the load, is less than or equal to the boiler OUTPUT size. If the indirect puts you over, in load size, the boiler water temperature won't catch up, till something satisfies.

If the indirect needs fast recovery at all load conditions, prioritize the water heater pump.

Noel

Tom Hughes

The Indirect gets priority

But what if I'm doing laundry, running the dishwasher, etc and its cold as hell outside?

Thanks Noel.

Troy_3

Vision piping

Simple--Efficiency! Why heat up a primary loop any hotter than the current load requires. Wasted BTUs.

Unknown

You'll get pink wrinkly fingers.

Seriously, most priority controls can be set up so that the heat will run after a preset water heater run time, like 30 minutes or so.

I had a relief valve open and stick open on an indirect, once. It was minus 20 out, and the house almost froze because the indirect had priority, and the control did NOT have this feature.

THAT house won't run on priority ever again. Good thing for the switch that allowed me to choose "No Priority".

Noel

Tom Hughes

Good point!

But in many cases I have multiple boilers. Gets more tricky and tradional primary/secondary would seem to be favorable?

Mark Hunt

Priority


I have yet to see an instance where a home became uncomfortable while a priority indirect called for heat.

The recovery of the indirect will exceed the demand and it will staisfy relatively quickly, long before the house gets cold.

If I am not mistaken, the Vision control will also kick the idirect out of priority if the demand is not satisfied within a certain amount of time.

Mark H

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Troy_3

Vision cascading control

Rumor has it that that function is coming. You didn't hear it from me.

Matt Connolly

Mark, I know just such a house...

where there was so much glass and it was high in the mountains - when the MZ went to recover the indirect for more than 20 minutes the house would drop in temp noticeably to the point where the HO kept having the tech come out to tweak it. A 15 minute interupt relay did the trick.
Matt