Circulators or zone valves?

DanHolohan

I'm curious. Which are you using these days for zoning, and why?

hot_rod

I think the availability and wide size selection of delta P circulators is allowing the pumped zone bunch to rethink zone valves
TRVs also seem to be gaining some popularity, a great match for ∆P circs.

BDR529

Circs. Because the low voltage wiring dosn't hold up to the coat hangers as well.

ChrisJ

BDR529 said:

Circs. Because the low voltage wiring dosn't hold up to the coat hangers as well.

So run heavier wire to the zone valves.

EdTheHeaterMan

I have used zone valves mostly. Honeywell was my choice. I liked the Erie Pop Top when I put my own system in, but found after 25 years there were issues with the body leaking and the valve not closing completely. Changed to Honeywell a few years back. The Heat activated hydraulic piston models take to long to activate which plays havoc on the recovery of indirect water heaters by adding another minute or two to the call for hot water from the tank thermostat until the boiler water actually is hot enough to start tov heat the water in the tank. If there are more than 5 zones, I might split the zone valves between two circulators.

Dave Carpentier

I have 7 zones on my in-floor with 1 pump and 7 zone valves with actuators on the return side.
The cost up front to instead go with 7 circs , and electricity to run them over time, would have been much higher.
With the original single-speed circ, it took quite a bit of time playing with the supply-side zone valves (using them as restrictors) to balance things out during random multiple zone calls (I have a wide variety of zone lengths). Once I switched to a constant pressure pump (in my case an Alpha-1), things got much smoother.

Paul Pollets

Mostly delta P circ pumps. The radiant systems use a delta P pump and are zoned at the manifold with telestats, if requested. I've no issue with zone valves being used since the availability of delta P pumps is widespread, and a pressure bypass differential isn't required.

Dave Carpentier

When I replaced my fixed speed pump with an Alpha, I spec matched it using the max speed curves, mistakenly ignoring the fact that it pushes slower in delta-P mode. So, less gpm but more balanced loop calls. Live and learn..

GGross

I do design assistance for contractors. We had a whole bunch of people switch to zone pumps with Grundfos Alpha pumps in the last few years. The electric company was offering big $$$$ for each pump, so much that the pump was actually free... They like them because it is an easier sell to a customer due to cost, I like them because the delta-p function seems to work well and eliminate a lot of the overpumping many systems around here experience. I have a few customers who like zone valves, I only use Caleffi zone valves unless the contractor is dead set on honeywell.

JohnNY

Zone valves are annoying. Finicky little motors and end switches or take-forever thermal actuators. Little wires. Some valves are loud when they close. Few are full-port.
You gotta move water? Use a darn pump.

ChrisJ

JohnNY said:

Zone valves are annoying. Finicky little motors and end switches or take-forever thermal actuators. Little wires. Some valves are loud when they close. Few are full-port.
You gotta move water? Use a darn pump.

Careful......... you're going to start another "it's not a pump it's a circulator" argument for 10 pages.

Tinman

I’m against any kind of over-zoning, but there are lots of jobs that require it like apartment buildings. I prefer a minimum number of zones and a minimum number of supply water temperatures. When zoning makes sense, zone valves with a delta P pump is my first choice. 

hot_rod

When I see a wall covered with residential zone PSC circs I always wonder how many, if any are running mid curve. A 007 or 15-58 on a 1 gpm radiant zone, hmmm. Rarely do installers plot a system curve, much less lay it over a pump curve.

I will say the new electronic circulators change, or can eliminate, most of the the mis-sizing issues. ECMs with DC motors have much more starting torque, so sticking circulators, which are as common as failed ZV motors, are becoming a thing of the past.

With a wide array of ECM circs now, one should be plenty for most any job, with appropriately sized ZVs. Using delta P mode with ZVs pretty much nails flowrates to where they need to be.

Labenaqui

We use Delta-T ECM Circs and Zone Valves exclusively. Minimizes distribution materials and energy costs, particularly when optimized by natural (gravity) convention (patented)..

GroundUp

My work is primarily large zones of radiant slab, so those typically get individual circs as one circ with zone valves tends to be less cost effective and I can adjust the speed (usually 15-58s) to meet the load. When there are multiple zones smaller than 4 loops, I go to an Alpha and Sentry zone valves or manifold actuators- sometimes both. IMO, anybody who adamantly says one is better than the other regardless of the job could use some more education. Both have their place.

Solid_Fuel_Man

I agree with @GroundUp

Each have their place. With a bunch of high head radiant a circ for each zone makes sense. Or with long runs of wildly variation in lengths. 

Or with only 2 zones, upstairs and downstairs, 2 circs make more sense than 1 circ and 2 ZV. 

I like the 007e and 0015e, and the Grundfos Alpha as well. Zone valves are always Caleffi Z-One. 

For a typical 4 zone fin-tube and 1 indirect residential job, I use an Alpha 1, and 5 ZVs. I really don't get the whole separate circulator for the indirect thing. Circ pumping away, and ZVs on the return. Not a flow check in sight. 

The Steam Whisperer

I prefer to use both on most larger jobs. We install two circulators in parallel with outlet flow checks that can handle the full flow need for the system when operating together and then use zone valves to control the zones. You now have back up built in and often can use small residential circulators for commercial applications... usually cutting the costs of the circs. and easing circulator replacement. We are usually using full or nearly full outdoor reset so the zone valves are open almost all the time, so there isn't much need for a variable output circulator.

Robert O'Brien

In this part of the world, it's 95% baseboard or recessed convectors. Can't really avoid over pumping, no circs small enough.