zone valves for constant circ system

Mark Hunt_6

to use a non-electric TRV with remote sensor?

That would work.

Mark H

1bourbon

zone valves for constant circ system

Are there particular styles of zone valve (heat motor, electromechanical, etc.) that are more or less amenable to literally being open constantly from say November to May?

Thanks.

Brad White_203

If

they are open constantly, and no one is there to hear them, are they really zone valves?

I would prefer, if you really must, to use 3-wire 24V motorized zone valves, the kind that do not need power to hold them open (or hold them closed for that matter). The "heat motor" types require power to heat the wax head and open them. Why draw amperage all winter?

But for your application? I would use a ball valve and tie a piece of yarn around one finger as a reminder

bob_46

Because

of a change in my control scheme I hot wired a MH zone valve. As you know they have an impedance protected motor so it sat there stalled for 26 years. I was going out of town and thought maybe I ought to just take it out of the system so I did. The other day I had a valve stick open so I replaced it with other valve, still works fine. One had a date code from 82 the other from 83. Other than wasting energy( the heat from the motor still goes in the house) I wouldn't worry about leaving a MH valve open. Boy, removing that valve was a big project I had to sweat two joints, that's a lot of work for a retired fitter.

Jed_2

Or GRAVITY


Why not just make it a gravity system, with Taco 2-way i-Series (Indoor Reset Zone Valves), and a good Mod/Con with ODR. Let the boiler do the work, and let i-valves play with your flow?

CC.Rob_11

unfortunately...

I'm fresh out of yarn, so I need a zone valve. Which meet the specs you describe?

Actually, there is sufficient intermittency (e.g. shoulder seasons, winter days with lots of solar gain), that yarn would do little more than slow my typing and require many trips to the basement.

The system in question is two zones of 3/4" fin tube that run on nearly full (down to 80F) ODR with indoor feedback. Supply at design (5F) is around 140F, achieved primarily by tightening the envelope over the past several years. The reference zone is nearly constant from Nov to May. The other zone is more subject to solar, occupancy, cooking, and other gains, so is intermittent.

It is presently driven by two circs. The new Wilos or the forthcoming Grundfos Alphas look so cool it's tempting to try one. A pair of energy-efficient zone valves that don't mind being open 98% of the winter would be nice.

Or maybe a couple very long pieces of yarn, attached to the ball valves.

TimS

which zone valve ?

first zone valve that comes to my mind is a Taco esp zone valve would fit this application affordable too.

1bourbon

maybe

Could the TRV go in place of a zone valve on the manifold, and the remote sensor utilize, say, 18/2 wire or similar?

The remote sensors would need to go very close to the existing locations of the thermostats and the existing indoor sensor. Their placements were optimized through a lot of data logging of the thermal behavior of the building.

gasfolk

Taco ESP NO

Our supply house stocks the Normaly Closed (NC) Taco ESP, but we special ordered the Normally-Open (NO) version. Low current draw allows up to 12 esp valves per 24-volt transformer. Inexpensive too.

gf

Tombig_4

My system is similar with solar gain moving from room to room changing the heat load the most. I am using mostly TACO EBV valves and a few Califi and Danfoss heat motor valves. The heat motor valves only draw about 3 or 4 watts each when on and the EBV is about 1 watt when on. 16 heating zones on a very low wattage Laing circ. only draws an average of about 20 watts.

Ron

CC.Rob_11

ebv

What is the standby draw of the EBV? The new version seems to have diagnostics and other stuff.

Tombig_4

EBV power

When it is off, zero. One minute after turning on, I measured between .8W and 1.5W.

Mark Eatherton

bob...

Have you never read Dan's book where he says to NEVER work for relatives, the church, or your own system?

Are you enjoying your retirement?

Are you in Colorado?

ME

1bourbon

define \"on\"?

Is "on" defined as "only when the valve is in the act of opening or closing," or as "from when it opens until it closes."

The former would be "on" for seconds, the latter would be "on" for weeks to months.

Thanks!

radiconnection

Honeywell/Sparco

The Sparco ZVs are open when the powerhead is unscrewed. Simply back off the power head when constant circulation is desired. The stat can be disconnected to save on the motor power--fly in the ointment is if you need the end switch contacts for control purposes.

Unknown

Oventrop makes a variety of valves that can be built into manifold assemblies, with remote-sensor capillary tubes.

figuring out the adaptor progression can be tricky, but it's doable.

Tombig_4

EBV power

Hi Rob,

They draw about 10 watts for a couple of seconds as they begin to open and then it drops down to less than 1.5 W as it finishes opening. I don't remember how low it got several minutes after it opened but it stayed below 1.5W. It took no power to close. It's the lowest power 2-wire accuator that I know of.

Unknown

Constant Circulation System

Hey Rob - here's our take (Mark Hunt, feel free to jump in here too) on constant circ systems, zone valves etc.

First, how about we change the word constant to continual OK?

I train using the concept that a heating system is "dynamic", loads, btu's, flows etc changing continously. Kind of like our bodies (heart is pump, vains are pipes - that kind of idea). Our bodies like continual circulation and flow changes when we sleep, work, etc - like a heating system where loads vary.

Now, lets use a variable speed circ instead of constant speed. If you could stand at the circ, watch the zone valves position change and adjust the circ speed down as zone valves close you would see more valves stay open and waaay less noise when only a couple of zones are calling (remember constant speed circs build pressure as flow decreases - and that is the essence of the problem - as zones are satisfied, lower btu's required, lower lbs of water and flows needed, lowering friction loss requiring lower differential heads provided by the probably oversized constant speed circ that wants to build pressure). The good news is newer "smart" circs adjust themselves (as Mark Hunt says "they do the thinking for you").

This concept will have you move closer to continual circulation - especially on those shoulder heating days!

It's one damn interesting industry ain't it!

CC.Rob_11

all aboard

I'm on board with all that. Just thinking about what valves will be least consumptive when it happens.

Thanks!