Circulators or Zone Valves

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Circulators or Zone Valves

Do contractors prefer using circulators or zone valves? Read what they have to say.

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DinoRoberti

Nice summary! ECM circulators are a game changer. Heat actuated zone valves consume lots of electricity. More efficient to use an ECM circulator for each zone. In addition, zone valves are expensive. Further savings can be realized by minimizing ECM pump on time. Pulse Width Modulated (PWM) thermostats should be used. Also, not using an outdoor reset further reduces run time. The savings in electricity from using a PWM thermostats and no outdoor reset are much greater than the savings of gas on a modern condensing boiler. And there are savings in electricity by using more high fire than low fire (less run time). PWM thermostats will result in similar heating performance as an outdoor reset. xxxxxxxxxxxxxxxxxxe

Lance

And there you have it. How man and industry learn on the fly how to get it right, that is until the next change we make to get it right.

FrankB101

Circulators hands down!

jbecker838

Great question and great comments. I prefer individual circulators when zones are lare or there are long runs. Small systems and small zones I use one circulator with multiple zone valves.

hot_rod

DinoRoberti said:

Nice summary! ECM circulators are a game changer. Heat actuated zone valves consume lots of electricity. More efficient to use an ECM circulator for each zone. In addition, zone valves are expensive. Further savings can be realized by minimizing ECM pump on time. Pulse Width Modulated (PWM) thermostats should be used. Also, not using an outdoor reset further reduces run time. The savings in electricity from using a PWM thermostats and no outdoor reset are much greater than the savings of gas on a modern condensing boiler. And there are savings in electricity by using more high fire than low fire (less run time). PWM thermostats will result in similar heating performance as an outdoor reset. xxxxxxxxxxxxxxxxxxe

Most all of the new thermal actuators are 250mA initial draw, 125mA holding current. 3W heat motors. Can a typical electric meter even read that low of a draw?

hot_rod

With all the talk of electrification and lack of power and transmission, brown outs, etc. Conserving power should be one of a a hydronicians top goals.

8- 3W zone valves + 1- 37W delta P ECM circ= 61W, figure 3000 hours per year at ?? Kwh rate=. Assume .25/ kwh, so less then $50 per year
And you have a near flat pump curve!

Or 8- 78W PSC circulators= 624W $468/ year
With ECM circs, maybe 312W $234/yr

20 year life expectancy for ZV and circulator add some inflation cost for the power=?

With those PSC circs running about 20% efficiency IF they are running mid curve, which is doubtful on an 8 zone 100K residential zone pumped system.

If you are using a 78W PSC circ to move a few gallons, as many zone circs probably are, efficiency is down below 10%!

Clearly an ECM and low current ZV wins cost of operation. And best matching the actual pumping requirement. Buy a spare circ with the $$ you save for redundancy

If you do zone pump, the ECMs make the best $$ sense also.

MikeAmann

Or 8- 78W PSC circulators= 624W $468/ year. Assume .25/ kwh.

Problem, this math assumes that all 8 circs are all running at the same time.

EdTheHeaterMan

hot_rod said:

With all the talk of electrification and lack of power and transmission, brown outs, etc. Conserving power should be one of a a hydronicians top goals.

8- 3W zone valves + 1- 37W delta P ECM circ= 61W, figure 3000 hours per year at ?? Kwh rate=. Assume .25/ kwh, so less then $50 per year
And you have a near flat pump curve!

Or 8- 78W PSC circulators= 624W $468/ year
With ECM circs, maybe 312W $234/yr

20 year life expectancy for ZV and circulator add some inflation cost for the power=?

With those PSC circs running about 20% efficiency IF they are running mid curve, which is doubtful on an 8 zone 100K residential zone pumped system.

If you are using a 78W PSC circ to move a few gallons, as many zone circs probably are, efficiency is down below 10%!

Clearly an ECM and low current ZV wins cost of operation. And best matching the actual pumping requirement. Buy a spare circ with the $$ you save for redundancy

If you do zone pump, the ECMs make the best $$ sense also.

Are you trying to make up a new job title? A Technician that works on Hydronics? Maybe you can get that word into the dictionary in 10 years. But I just looked that up in my Funk and Wagnalls ...and it isn't there!

But I will add it to my signature line!!!

reframmellator

As I sit here typing, I'm pretty convinced of the benefits of a zone valve having an absolute shutoff.

I'm a homeowner who just replaced a 26 year old Lochinvar MIniFin. The old setup was two zones controlled by Honeywell zone valves, with the circulator at the boiler on the return side. I had one valve motor head failure in that time. The new setup has one Taco circulator for each zone, controlled by a relay board.

Each zone has about a 120 foot run around the perimeter of the home, plus supply from and return to the boiler. Zone 1 heats the first floor and works fine. Zone 2 heats upstairs and we "randomly" get hot water leaking through. Zone 2 starts upstairs in the master bedroom, where the thermostat is. Sometimes it holds the entire upstairs at setpoint, and other times the thermostat can read as much as setpoint + 7 (75 v 68).

The contractor is a well regarded local outfit. They have been responsive and I have no doubt they will make it right. On the first callout, they replaced the backflow preventer in the circulator. On the second callout, they installed flow control valves downstream of the circulators in each zone. The only explanation I have for this is FCV failure in Zone 2. We've verified the wiring is correct.

I got three quotes, and all recommended circulators. I understand their arguments, and the system is nice and quiet. But right now I miss the positive shutoff of a zone valve.

reframmellator

I should have added that the Zone 2 overshoot comes solely from the leakage. Baeeboards in the other bedrooms range from barely warm to cold.

Mad Dog_2

Use both. Working elbow to elbow with Jimmy The Gent Burke on boilers, we often used ZVs when 🤔 economics dictated such.  All circs were an upgrade.  Sometimes, we'd argue if a valve or drain was really necessary but he came from the oil company-boiler a day pedigreen.  Like an older brother who was 12 yrs my sr., he often won...."You DON"T NEED THAT!!!!"   The Great  Ron Jr.  Lives this each day.  They ran a tight, economical boiler crew that got it done neat,  lean and simple with a minimum of valves and fittings. Triple Crown's philosophy was "When you expect excellence AND you're willing to pay for it!." Everytime we DIDNT put an extra valve or drain in we'd regret it after you get whole system filled and now ya got a leak with no valve orctee w drain to isolate it!   Mad Dog.

hot_rod

reframmellator said:

As I sit here typing, I'm pretty convinced of the benefits of a zone valve having an absolute shutoff.

I'm a homeowner who just replaced a 26 year old Lochinvar MIniFin. The old setup was two zones controlled by Honeywell zone valves, with the circulator at the boiler on the return side. I had one valve motor head failure in that time. The new setup has one Taco circulator for each zone, controlled by a relay board.

Each zone has about a 120 foot run around the perimeter of the home, plus supply from and return to the boiler. Zone 1 heats the first floor and works fine. Zone 2 heats upstairs and we "randomly" get hot water leaking through. Zone 2 starts upstairs in the master bedroom, where the thermostat is. Sometimes it holds the entire upstairs at setpoint, and other times the thermostat can read as much as setpoint + 7 (75 v 68).

The contractor is a well regarded local outfit. They have been responsive and I have no doubt they will make it right. On the first callout, they replaced the backflow preventer in the circulator. On the second callout, they installed flow control valves downstream of the circulators in each zone. The only explanation I have for this is FCV failure in Zone 2. We've verified the wiring is correct.

I got three quotes, and all recommended circulators. I understand their arguments, and the system is nice and quiet. But right now I miss the positive shutoff of a zone valve.

So you went from bad to worse by making the change from ZV to zone pumps? Still not working after firing a shot or two of the parts cannon?

Assuming 70' of 3/4 baseboard, 16 ells a few valves and 150' of 3/4 copper tube, here is the SIM with a common fixed speed PSC circ. Running top of the curve, maybe 15-18% efficiency. Times 2 if you have a similar 2nd zone.

Nice and quiet is possible with ZV or zone circs, what was their argument for zone pumps?
That temperature overshoot in addition to lack of comfort also costs you fuel $$.

Pump manufacturers also sell zone valves. An ECM delta P and two zone valves would have been state of the art. Assuming the boiler is piped correctly.

Derheatmeister

Great question... Finally, we are seeing such an increase in electrical/Fossil fuel costs which has sparked these long overdue coversations questioning proper designs / lifetime operation cost / breakeven points and ROI.

As some of you may know the European Auto delta T/Auto Delta P derivative less power consuming EMC circulators have been around for a very long time and the proper applications for these "Smart/effizient" circulators has been heavily misunderstood here in the USA.

Especially in a single zone with a fixed flow rate such as a bedroom in a multi zone situation these circulators are missapplied. Serious Industry professional actually sometimes refer to these systems as a "Pumpaholic" system..or the plumber has stock in this manufacturers company.

The manufacturers of these pumps do not mind selling more of these pumps and therefore they turn a blind eye to this misapplication !

Yes...The wire consumption is reduced by switching out older style circulators for a "nice new" Auto delta T/Auto Delta P derivative EMC circulator.
However at this Point and for what is available on the US market, if these circulating pumps are applied as Zone circulators vs just ONE EMC circulator in conjunction with low energy consuming Zonevalves, it is hands down an increased carbon footprint/reduced ROI .

A couple years ago at the ISH Frankfurt, Wilo, which have been the poineer (Inventor)of Delta T,Delta P circulating pumps, introduced a very small zone circulator pump (DC voltage).
After conversations with some of the engineers the answer to availability for the US was "Not for the US market" Maybe they will have a change in the mindset if the market supports these Micro circulating pump vs Zonevalves.

In my book at this time and to follow the KISS concept :
Conserve first by utilizing better building techniques.
Then >>ONE<< Auto Delta P or a combination p/t derivative EMC circulator combined with no energy consuming Thermostatic Radiator Valves in conjunction with Deionized water as a transfer fluid and large amounts of heating surface on constant flow...The heat is supplied by a Drainback style Solar/Geo/Alternative energy source/ passive solar which is assisted by Modcon boiler with the proper Curve/Shift settings modulating from the fall to the spring time based on Outdoor reset.
Or maybe the hydrogen plasma concept is not that far out and electricians will take care of our
comfort via a daily dose of Radiation 😒

Sorry for the Germenglish explanation.

OuterCapeOilguy

I am primarily a repair/maintenance person, and have done very few hydronic installations. The few I have done have used both approaches. In my own home, I installed 4 zones (including the dhw). I have a W/M WGO-5, indirect dhw, and a Taco 007 on the supply side, using Honeywell motorized valves. System operates flawlessly, and in 14 years I have never had to touch the pump or the zone valves. The only potential downside is that when a system is zoned with circulators, having one pump down isn't a life-changing experience. On the Cape, we are expecting temps on the night of Feb. 3 in the 0ºF-1ºF range. Having a pump fail on a single-pump zoned system could be a disaster. Nevertheless, I prefer it.

hot_rod

OuterCapeOilguy said:

I am primarily a repair/maintenance person. In my own home, I have 4 zones (including the dhw). I have a W/M WGO-5, indirect dhw, and a Taco 007 on the supply side, using Honeywell motorized valves. System operates flawlessly, and in 14 years I have never had to touch the pump or the zone valves. The only potential downside is that when a system is zoned with circulators, having one pump down isn't a life-changing experience. On the Cape, we are expecting temps on the night of Feb. 3 in the 0ºF-1ºF range. Having a pump fail on a single-pump zoned system could be a disaster. Nevertheless, I prefer it.

you can buy a spare circ like that on e-bay for under 50 bucks. cheap insurance even if it is an expired date code:)

knotgrumpy

One delta P pump with TRV's - Smooth!

A few years ago I took out all of the 1" iron piping and Monoflo T's in our hot water system along with the 5 pumps feeding the zones. Some were still the big B&G two piece jobs along with a few smaller Grundfos.

I redid the piping with Veiga Fostapex (Loved it, don't think they make it anymore?) in a reverse return configuration and put TRV's on all of the radiators and convectors.

One Ecocirc delta P circulator takes care of the supply/secondary side based on the various TRV's opening/closing.

Flawless operation. Circulator runs continuously on one of the lowest settings and sips power. 6 years so far on the one circ.

Downside is I still am running an older WM CGi, and while very dependable, it is sending a lot of money up the flue that could be condensing for some gains in efficiency. It is on a primary loop with a small variable speed Ecocirc running at minimum setting continually. Primary loop is like a raceway that secondary loop drinks off of as it needs to. ESBE thermostatic valve protects boiler from condensation. (Sorry Hotrod, should have bought a Caleffi!)

I have a few of the smaller circs left on the shelf if I ever need to get through a pump failure.

I don't know if I did it right, but it has been reliable and air free. Quiet, too.

Alan (California Radiant) Forbes

Downside is I still am running an older WM CGi, and while very dependable, it is sending a lot of money up the flue that could be condensing for some gains in efficiency.

If you've got a high temperature system (radiators, fan coils, etc.), you won't be condensing that often with a condensing boiler. And any savings you realize will be offset by the cost of all the condensing boilers you have to replace every 15 years. Don't take your phrase, ".....while very dependable" lightly.

EricPeterson

Alan (California Radiant) Forbes said:

Downside is I still am running an older WM CGi, and while very dependable, it is sending a lot of money up the flue that could be condensing for some gains in efficiency.

If you've got a high temperature system (radiators, fan coils, etc.), you won't be condensing that often with a condensing boiler. And any savings you realize will be offset by the cost of all the condensing boilers you have to replace every 15 years. Don't take your phrase, ".....while very dependable" lightly.

Let's not forget this chart:


According to the chart, efficiency goes down as water temperature goes up.
Source: Modern Hydronic Heating, 1995, Siegenthaler, pg 45.

The sum of which is why I went with a traditional CI atmospheric boiler with 85% efficiency.

Eric Peterson

hot_rod

You could do the number crunching, determine how many days the boiler could cover the load while running in condensing mode.
Hours of occurrence Dara and the output charts for your heat emitter, basically.

Mod cons can also save a small% with the modulation function. Especially if a standard boiler short cycles often. That could drive the boiler below 80% efficiency

reframmellator

hot_rod said:

So you went from bad to worse by making the change from ZV to zone pumps? Still not working after firing a shot or two of the parts cannon?

Assuming 70' of 3/4 baseboard, 16 ells a few valves and 150' of 3/4 copper tube, here is the SIM with a common fixed speed PSC circ. Running top of the curve, maybe 15-18% efficiency. Times 2 if you have a similar 2nd zone.

Nice and quiet is possible with ZV or zone circs, what was their argument for zone pumps?
That temperature overshoot in addition to lack of comfort also costs you fuel $$.

Pump manufacturers also sell zone valves. An ECM delta P and two zone valves would have been state of the art. Assuming the boiler is piped correctly.

The primary argument made by everyone who quoted was reliability - if one circulator fails, the whole house is not down.

So it all ended well, as far as I am concerned, Contractor replaced the flow control valve in Zone 2 with a Taco Zone Sentry valve tied to the circulator. Now Zone 2 (upstairs) is isolated when it is not calling for heat and the loop is maintaining setpoint and all rooms upstairs are comfy cozy.