Zone Valve location question:

Chris_57

Please forgive my ignorance, but I have a question regarding zone valves.

First, there seem to be several opinions on how to stop ghost/gravity flow when a zone isn't calling for heat. Some people belive a swing check should be installed on the return side of each zone, others say to create a thermal trap. It is my understanding that swing checks tend to chatter.

My question is this:

Can I install the zone valves on the RETURN side of a secondary loop and use a TACO 007 with integral flow check on the supply side? Why/Why not?

Thanks and sorry if there is an obvious answer to this question.

hr

Sure you can

but a soft seat spring check would also work, be less expensive, and would not require power to operate. Yes, swing checks, even on a vertical line, tend to be noise makers in hydronic systems.

Flow check, the weighted type, are another non electric option.

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Unknown

I'd choose either method

Using IFC circs on the supply and zone valves on the return is overkill , in my opinion . We are new to using IFC circs so I'll reserve my opinion about them bypassing . But before them we used either regular Tacos with weighted flowchecks , or zone valves above the system circ on the supply . No check on the return , ever . Never had a problem with heat bypassing , except for crud getting stuck on the flowcheck . And that was one in thousands of zones installed .

paul sr

Just curious, why no flow check on the return? Paul sr.

Unknown

Never needed one there

The weight in the flowvalve holds the hot water down on the supply side . It's also a flowcheck , stopping flow going in reverse . I've personally seen less than a handful of heat bypass problems , we changed the flowvalve on the supply and stopped the problem right there . I would guess you could get heat up from the return if some radiation is close and higher than the boiler , but I've not seen that happen yet .

hr

Primary secondary

piping adds some different flow dynamics than a basic pumped series piped boiler. Those generally work, without ghost interference with only one side protected.

In primary secondary there are a number of forces trying to rob BTUs from the primary loop. Often unbeknownst to the operator. I would highly recommend protecting both supply and returns on all secondaries piped from a primary loop.

In this link are some methods shown with pictured examples.

http://www.pmmag.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2379,13972,00.html

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