Zone valves or pumps

Robert O'Brien

these circs are so unreliable,why would I want 6 when I only need one? And what about manually opening a failed zone valve?What result would that yield? In the vast majority of residential high temp applications,zone valves will have a much lower life-cycle cost

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realolman

I'm seeing zone valves for $80 circ pumps for $60 3 zone relays for $99 ... any preferences or advantages to zone valves or circs for baseboard heat?

hot_rod

I look at the amount of BTUs to be moved

generally my zones require 1-4 gpm. A whole house rarely over 100K. So 1 circ easily does that work with zone valves as the zone control mechanism. Most small wet rotors have their sweet spot around that 6-8 gpm figure, so they operate at peak efficiency at design load.

Plus the power consumption of one 80 W circ as opposed to 4, 6,6 or as many as a dozen circs on some jobs we see!

I may change my opinion as we see more and more ECM circs hitting the market.

Been playing with some Grundfos Alphas and watching them do a fine job at 7- 17 W consumption!

hot rod

Kevin_54

Ahh- The great debate. Zone valves or circulators? With zone valves you generally have only one circulator controlling all of your zone valves, so if the circ goes down heat is pretty hard to come by unless you keep a replacement circ on hand. With circs if you lose one you still have all other zones running until you can get it replaced.

Unknown

WILO Stratos Eco

Hey Hot Rod - Guess I'll have to send you some of our Stratos Eco pumps for testing (and press) ;-)

Our North American version will be out soon - do you want to wait or can you use the 230/1 volt European non-UL version with unions? How many do you need?

An important benefit of "smart" circs, remember that relatively inexpensive zone valve (the last or second last one to close) tries to close against the highest head the constant speed circ produces (at low flows). It has an easier job closing against the reduced head a "smart" pump generates. Quieter systems too with no need for a pressure by-pass.

"Smart" pumps are not only about energy efficiency but will solve quite a few potential start-up issues. Next time I'm in your area come to a class (week of Oct 15th I'm in the Denver area) and we can discuss. The Brain Box shows this very well.

Brad White

I am with Steve, Hot Rod and Robert on this debate

I used to favor circulators over zone valves for reliability and positive flow/faster response than many zone valves. Not all zone valves, just many. You would have to wait for your heat.

If I *did* use zone valves, I favored motorized types such as Belimo once they became more common not "heat motors" and as a refinement would use a DP bypass valve. Absent a DP bypass valve, the circulator just rode the curve and usually worked out fine. Circulators just made sense especially when multi-speed units became available.

What escaped me was the collateral cost of running all of those circulators over the life of the system.

Nowadays, with constant circulation and especially Variable Speed Circulators which constantly adapt, control valves or TRV's respond quickly enough.

Overall the "transportation cost" of moving the water is greatly diminished. A 3-zone house using 65-85 Watts per zone (WAY over-pumped per BTU), can be handled with a single circulator of the same type yet ramp down to actual needs. Running circulators on constant delta-T is exciting to me. Hold me back.

Hot Rod said it especially well and has real numbers to back it up. Give me an ECM as a first choice but any good variable speed regardless, if I have a say in the matter.

Weezbo

My first consideration is cost over time....

running concurrently with reliability.

When i was a bit younger design was super limited ,what on earth would i Need something other than A B& G to run the entire system

from those stone age days ,came "enlightenment" .

That led me to actually take some time and effort to investigate what actual flow rate at what head and resistances in pressure one could expect in the realm of possible scenarios at different temperatures and with variable unknown solutions flowing about within a system.

That basically led me to the conclusion that quite often even our smallest circulators like the grundfos and taco were more than sufficient .so, zone valves became my choice.

then i heard of a Wilo circ pump that was available in Canada...so, I called the company and as luck would have it i caught them as they were about to release something other than information.

I lost the gentleman's name when my computer crashed three years ago. However , I asked him if i might get some more accurate information.,although i considered the information was fairly up to date as it was presented by Hot Rod in a blurb on some new circs at the time. Being a rather interested individual i called Canada and asked if we could get some maybe ten sent to Alaska. then i would install a few drag my friends by, tell them that i bought one for them...they would go out design a system bolt one up pretty soon, we would simply have the solution for the demand...

I mentioned to the Wholesalers that they might want to take a good look at the offerings From Wilo.

Well, we had a wholesaler with some vision..they purchased a group of the regular garden variety circs..i chirped them up, bought one of the 3 speeds ,gave it to another friend of mine asked him to check out the curves on this momma:) and the first stash of Wilos is pretty much sold. What we need to see however, are the remainder of the product line that are DP ecm driven with the various levels of control.

Siggy and the Bean gave some very cool classes that i am honestly envious of my southern friends that could travail their lives to the class.The Bean , an inspirational dude for certain, put together class rooms on DVD back then so people living along some river over the mountains might have a better go at designing their new systems with Currently available information of various strategies to control flow rates.

Take a look at RPA offerings on the topic .


Well, i am off to work. i have to check my radiant ,temporary heat tool spin in some ABS ,so i can hurry up the electrician and insulators ,sheetrockers ..to get my SlantFin Eutectic with a Taco Variable speed injection lashed up.
Sure would be nice to See some of the smaller circs. this lash up only has 3 zones and an indirect.

*~/:)

Tim_41

I am redoing my heat in our house. Mod/Con radiators and also radiant. I would love to see the WILO resdential ECM circ here now.

zeke

economics

Could you give an idea of the cost of one of these ECM stratos so that one can determine its cost effectiveness.

Also, in a multizone application, if delta T is the control function, then wouldn't you have to balance zones fairly accurately?

Brad White

No cost data currently

but I have heard a 2.0 to 3.0 multiplier over a standard 3-speed circulator. That may well be true today and the cost should come down as demand and production volume increases. If I did have a MSRP, I am not sure I would post it here if it were not already public.

Your point remains excellent however.

Even so, it is incumbent upon any practitioner to work out for a customer/owner/end user a net present value or total life-cycle cost for a system. Essential to this is using the average useful life of components, escalation in energy cost over the time as well as any maintenance over the expected lifespan.

A couple of years ago, I could not justify on strictly economic grounds the use of a variable speed circulator on small systems. The Watts drawn were relatively low (high BTU per Watt ratio) but I could hang my hat on superior control. That is part of it, sometimes variable speed gives you tremendous control, especially in an injection system.

As for constant Delta-T control and any system for that matter, yes, balancing is critical to each emitter. This is why I favor using wye pattern balancing valves (Macon, Tour and Andersson, Oventropp are three I like).

Another school of thought on this (across a wide range of system sizes) is the following:

On constant-circulation variable speed/variable volume systems, if each terminal has individual temperature control and the pump can respond to delta-P -at least delivering flow to the furthest reaches- the system will self-balance.

In other words, each zone, radiator, emitter, properly controlled, will take what it needs and no more. All terminal equipment will be satisfied on a basis of need.

I have not embraced this fully to the point of not specifying balancing valves (OK, call me chicken) but I certainly am no longer going to install a balancing valve in the discharge of a VS circulator. Like driving with the brakes on.

Still, I can see the efficacy of eliminating balancing valves in favor of excellent local control. That means ALL emitters, no bypasses.

Constant Delta-T, on the system side, makes additional sense for the reasons stated. The assumption is that there is enough flow/pressure differential to meet the furthest unit as stated. After that, it is all Delta-temperature.

Kevin_54

Just like i said-The great debate.

zeke

Brad,
Excellent response.
Thanks so much.

Ron Schroeder

Me too. Or the Grundfos Alpha. But it doesn't look like residential sized ECM circs. are available to mere mortals yet.

I have always prefered two circs. one for the indirect and another one for all of the zones, using low wattage zone valves.

Alan(OnVacationInOregon)Forbes

Debate

I've always liked zone valves over pumps; seemed like way too much push for just one loop. Trouble is finding a reliable one.

I think I've run through almost every zone valve made - tell me if I'm missing any:


- Honeywell

- Erie

- Automag

- Flair (yes, there are still some out there)

- Edwards Engineering (ditto)

- B & G

- Taco ESP (ouch!)

And now have finally settled on Danfoss.......wax pellet activation which makes it very stable and reliable.

ALH_4

Caleffi

I agree that Danfoss valves are nice. Caleffi also has very nice zone valves in my opinion. They seem to be very reliable and well designed. They also have quite a few variations, both thermal and motorized. My only complaint about the standard thermal operators is that there is no indicator to tell you whether they are open or closed.

Kal Row

the wilo \"stratos\" are here and now!!!...

i will be going to them in a big way - as my newer designs really look at the electric cost - so i do small pumps on the radiant manifolds – which are injection fed off zone valve’d manifolds, driven by a vari-speed pump, and all my commercial jobs now have VFD's (VariableFrequencDrive) on the large pumps, i set the torque output for a specific head differential with all zones open and then let the vfd do the rest.
the result is that the pumps are operating at 20% current draw most of the time

dont get me wrong, i am not saying the alpha's are bad - just been hard to get, but the alpha's are great - and you can bet that as soon as the market for these take off, b&g, taco, and armstrong will have them too - it's not rocket science - there are a gezillion ECM motors out there in computer fans and disk drives - not to mention the solar market, which is really driving innovation in the power consumption area

I have also talked to danfoss and eri about making zone valves that don’t use power when not moving, ie: the motor that opens it, winds up a return spring, and mechanically latches at the end of the travel, where an end switch also turns the motor off, but the still applied zone power keeps a capacitor charged and a switching transistor to a latch release coil gated to “off” (less than 1va draw), and as soon as the zone’s power is removed, the now un-powered transistor can no longer block the current flow and the current to the latch release coil discharges across it – but it will probably add $50 to the zone valve’s cost – even though it only costs a small fraction of that per valve in bulk manufacturing – because of the cost of design and tooling etc… - it could even be added to existing valves as a replacement motor head – I didn’t talk to Honeywell as they move way to slow for me

Of course we are all still waiting for the wilo ecm micro pumps that siggi is running around with – that could revolutionize everything

some links:
http://www.wilo-na.com/cps/rde/xbcr/na-en/NA_Stratos.pdf

http://www.wilo-na.com/cps/rde/xchg/na-en/layout.xsl/1844.htm

ALH_4

ZV

Sounds to me like you're looking for a 3-wire zone valve? With constant circulation, it does start to seem foolish to use NC zone valves.

Unknown

As long as the pump that dies isn't the boiler pump, then you're still SOL with a zone pump system... unless you're not doing P/S piping.

Unknown

I haven't seen a single erie fail yet. what was the problem, and when were you using them?

ALH_4

Debate

So much for the debate. ;-)

Weezbo

KAL , it is a bit like...

looking at a seven course photo graph of a hot meal while at that indeterminable stage of consciousness betwixt hungry and starving..

the one we have seen is the one Lashed up Beta tested in the church ....the small ones might be on the open market buh not around here...

on another note, i would say the Caleffi & Erie are some excellent valves.The honeywell is slow acting for a reason...an old hardy zone valve is the White Rodgers 2 and 3 wire ... The Taco I series is dis similar with the ESP's as the actuator seemed to be the minor technicality on the ESP.

Alan(OnVacationInOregon)Forbes

True,

the Eries are very reliable, but I keep a stock of pop-tops and older operators on my truck. The problems have been either failure to open or fails to close end switch upon opening.

Ron Schroeder

Hi Kal,

Who has the smallest Stratos in stock?

Ron

Kal Row

with 3 wire you need new zone controllers...

people have enough trouble following wiring diags for the 2 wire ones, besides - it's not really constant circ, cause the smaller wilo ecm pumps will actually stop when dead headed by all zv's being closed, and pulse the motor every few moments to flow test until a ZV opens at least that what they told me - could be pie in the sky

ElectroniclyComutatedMotors, have permanent magnet rotors and don’t have anywhere near the starting current that PhaseSplitCpacitor motors do, so they can do that without burning the motor, or racking up a bill, especially if you have the older style mechanical electric meter which cant accelerate fast enough to register the pulse

Kal Row

Economics? Siggi has been trying to hammer home a point..

Of getting people to look at pump’s lifecycle power cost, even without taking into account the constant projected electric price increase – a quick calc, and you will see that the price of the ECM pump is sooooooooooooo moot – even if you are doing a retrofit where you have already paid for the PSC pump!!!

Kal Row

try dellon sales on dan's isle of long...

they promised, now make them deliver!!!