individual pumps versus zone valves

MarkH

most radiant floor heating diagrams I've seen use electrically actuated zone valves. (<a href="http://www.plumbingstore.com/zonevalvespecs.html">example</a>)
But recently I saw 2 different ones that specified individual grundfos pumps for each zone. Sounds like it might be a simpler setup for a small house. What is your opinion?

<a href="http://www.radiantcompany.com/images/newstdclsd.jpg">here's a link to one</a> at http://www.radiantcompany.com/ or this other one at http://www.blueridgecompany.com/
<img src="http://www.blueridgecompany.com/images/PanelDescription.jpg">

Canuck

Pipe Configuration

Certainly if the piping is configured in a primary/secondary loop fashion,or has injection mixing, the secondary loops will require pumps. If it's configured with supply and return headers, I'd say go with the valves.

heatboy

Overkill.

I don't see the point for something like the picture proposes. With only 3/4" S&R piping, one pump and zone valve would seem to be a much more efficient panel. 4 pumps at 75 watts per pump (300 total watts) as opposed to one pump 75 watts and zone valves equalling, maybe, 80 watts. If the system is large enough to demand 4 pumps, a thermostatic valve is not the way you would go anyway due to the high delta P though the valve.

I know some will say about if one pump dies there are three others, but I don't design with failure in mind. Efficiencies, such as piping and electrical loads, should be our main goal.

hb

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hr

I think

like hb, rarely does every zone need a pump of it's own to move the load. What are the BTU requirements of the various zones? Generally one small circ can handle the entire load. Two possibly, if you have several temperature requirements.

I lean towards zone valves, buy will zone with pumps if the load requires it.

Those looks like bronze bodied pumps in the pic. A pricey pump if you don't need non ferrous components!

hot rod

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Mark Wolff

I agree

And who has the cash to buy individual Grundfos circ pumps for every zone?

heatboy

In the application pictured above.......

It is no doubt less expensive to do it this way, rather than zone valves. You would need 2 pumps and 4 valves, which would probably cost more and the panel itself would also have to be enlarged to house it all. The bronze pumps used here are undoubtedly designed for an open system. The ZCPs from Danfoss use some bronze/stainless pumps, at least on the ZCPHX series I apply to water heaters.

hb

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