Taco Zone Valve Question.............................(Starch)

John Starcher_4

....the internal workings of the Taco 3-wire zone valve head? (model 555-050rp)

These things always confuse me. I'm trying to troubleshoot a system, and I believe the problem to be either bad heads, or the system is miswired.

It seems that terminals 2 and 3 are electrically common all the time, whether the valve is powered or not? At least that is what my test meter tells me on a new head I took off the shelf. Does someone have a wiring diagram for these, other than the microscopic one that is on the head itself? I'm trying to figure out how the internal switching of this valve is supposed to work!!

Thanks in advance,

Starch

Dale

WM book

One of the best and most useful things WM sells is the "Boiler Zone wiring guide", if you can pick one up from a WM wholesaler, mine cost $10 in 1995 but it's worth whatever it costs now. Just about every zone valve made is shown connected to different WM boilers. What I use often is the zone valve part. Yes the #2 terminal is common to the heater and the end switch it goes to the C of the 24 v tfmr. the end switch is between 2 and 3 and the motor (heater) 1 and 2. The thing about these valves if you take a head apart is the thermal switch that cycles the heat motor to keep it open but remove power for a time when it's calling. I don't know the time sequence, perhaps someone from Taco will comment. The main check with these is to have 0 volts on the end switch leads with all zones calling for heat BEFORE you connect to the control.

Mark Hunt

Taco


Coil between terminals 1 and 2. N/O switch between terminals 2 and 3. Terminal 2 energized constantly. Terminal 1 voltage broken through t-stat. The plunger is pushed down when the coil is energized and if you look closely, you can see the switch.

Check for cotinuity between 2 and 3. Unless the plunger is down, you will get an open circuit.

Mark H

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Ron Schroeder_2

Would the end switch close if the head is removed from the body on the usual TACO zone valves?

I only use the TACO ESP valves so I can't answer this question.

Unknown

John, I am going to send

you a FREEBIE on zone valves. It covers all the concerns you have plus a few others. There are by the way a couple of tricky little wiring scenarios with the three wire TACO zone valves. These are also included in the material.

As for the ESP Taco zone valve that is totally differetn from the 555 heads. It is a four wire capacitor start type of zone valve with very low amperage draw.

We cover all of that in our Hydronic Controls class by the way.

John Starcher_4

Ok, now I think I have it!

Thanks to all for your replies.

Tim - I'm going to plan on coming for the week in February! Just have to confirm some things, schedule-wise.

What had me confused was the fact that I was reading continuity from 2 to 3 on a brand new head I took off the shelf, with it just laying on the work bench unpowered! Come to find out, if I push the plunger with my finger, the switch opens. As soon as I let go, the plunger "creeps" out a little bit - just enough to activate the switch. Evidently when the head is installed on the valve this won't happen, but that continuity reading was REALLY messing with my mind!!!!!!!

Must be a Monday!

Starch

Unknown

John look forward to

seeing you in February. I will still send you the handpout on Zone Valves.

Joe Mattiello

Taco, Inc.
Joe Mattiello
Technical Service Technician
joemat@taco-hvac.com
401-942-8000 X 484
www.taco-hvac.com

Joe Mattiello

The zonevalve is typically control by a thermostat setting closing sending current to terminals 1, and 2 expanding a substance that pushes the piston of the element down against the valve stem. The conical cam at the end of the piston and the tab just above it actuate the switches. As the piston moves down, the contacts inside the enclosed end switch close. This completes the circuit through terminal 2, and 3. An interruption of current to the power unit heater occurs in the fully open mode because the outer blade of the stock switch is deflected causing the heater contacts to open, interrupting current. As the piston retracts slightly, the heater contacts meet again and the slight back and forth motion is repeated as long as the thermostat contacts are closed. When the thermostat is satisfied, its contacts open and cut off current to the power head heater. The element cools, the expandable substance contracts and the valve closes opening the end switch.
Taco, Inc.
Joe Mattiello
Technical Service Technician
joemat@taco-hvac.com
401-942-8000 X 484
www.taco-hvac.com

John Starcher_4

Thank you, Joe! (no message)

.

Glenn Harrison_2

Joe,

Is the complete Taco zone wiring guide available in pdf form somewhere?

Thanks, Glenn.

Joe Mattiello

at www.taco-hvac.com

Hit on products, electronic controls instruction sheets.
Taco, Inc.
Joe Mattiello
Technical Service Technician
joemat@taco-hvac.com
401-942-8000 X 484
www.taco-hvac.com

Glenn Harrison_2

I think I'm blind...

I found the wiring guide for the Pump and Zone Valve Control Panels, but I was looking for a wiring guide for connecting Gold Zone Valves to each other and individual controls before Panels were available. I had one years ago and can't find it, and would like to have something to give our newer guys to help them on service calls where 2, 3, 4, 5, or more zone valves are wired to a boiler pump control or aqua-stat relay.

Thanks, Glenn.

Unknown

Glenn,

> I found the wiring guide for the Pump and Zone

> Valve Control Panels, but I was looking for a

> wiring guide for connecting Gold Zone Valves to

> each other and individual controls before Panels

> were available. I had one years ago and can't

> find it, and would like to have something to give

> our newer guys to help them on service calls

> where 2, 3, 4, 5, or more zone valves are wired

> to a boiler pump control or aqua-stat

> relay.

>

> Thanks, Glenn.

Unknown

Glenn,

> I found the wiring guide for the Pump and Zone

> Valve Control Panels, but I was looking for a

> wiring guide for connecting Gold Zone Valves to

> each other and individual controls before Panels

> were available. I had one years ago and can't

> find it, and would like to have something to give

> our newer guys to help them on service calls

> where 2, 3, 4, 5, or more zone valves are wired

> to a boiler pump control or aqua-stat

> relay.

>

> Thanks, Glenn.

Unknown

Glenn, I have what you

are looking for if you e-mail me your address I will mail it off to you.

It also includes some unusual situations you may run into with Taco Zone Valves and how to wire them.

Glenn Harrison_2

Tim, Thank you

I honestly really hate to ask you for this, only because you have already done me so many freebie favors that I still have to return the favor of. One of these days I'm going to save a few extra pennies and buy some of your manuals! That's a promise!!! It's the least I can do.

Thank you again, Tim. E-mail is on the way.

Glenn

Unknown

Glenn, glad to help out

I a just sent one to John Starcher so I really cannot refuse you as a long time friend here on the Wall. Merry Christmas it will go out as soon as I get an address.

soot_seeker_2

a few taco zone valve questions

hi,

some further questions on the taco zone valves:

1. do i understand it correctly that the ESP series doesn't care about the mounting orientation as compared to the 570 series? (do the 570 series only mount horizontally?)

2. also, it seems that the esp series use about 1/3 of the current required by the 570's and the esp's seem a little less expensive and they give you both a n/c AND a n/o featured end switch. why would you use a 570 over an esp? is the wiring basically the same?

3. also, is the 24v xfrmr normally included inside the zone controller or is it typically supplied externally for taco?

thanx

Unknown

ESP and 570 are entriely different

valves.

ESP can be mounted either way there is no direction of flow. It also has a smaller footprint so it can be put in places the 570 cannot.

There were a couple of problems with ESP series 1 the Series 2 has solved those. It no longer has the NO/NC function to the best of my knowledge. ESP use a Prostar Capacitor which is an energy storage device instead of the high amperage draw of the heater power unit of the 570. The ESP can run 12 zones from a 40 VA transformer while the 570 can only run three. The ESP also opens faster (6.5 seconds) than the 570. The ESP problem of not being able to be used with "power stealing" thermostats has been solved in the Series 2 model.

The ESP is a four wire valve with "dry" end switch contacts which is an advantage over the 570 which has terminal 2 common to both terminal 1 and terminal 3 which at times has presented some problems.

Power to the zone valves both ESP and 570 is from an external transformer or from the T - TV - Z circuit on a combination relay or triple aquastat relay.

soot_seeker_2

thanx


ahhh. nicely explained.

i like the 'dry' contact idea better.

i was trying to figure out why people kept referring to the 570 series as a 3-wire valve when the pdf above obviously showed 4 wires going to it. i gather they really meant 3-terminal since your explanation would indicate that the esp series had at least 4 terminals to handle the coil separately from the dry switch.

lastly, it occurred to me after looking at the prices of the zone valves combined with the price of the zone controller (plus opportunity for increased possible failures) that one might still be better off going the 'lo-tech' approach using separate circ pumps for each zone and foregoing the valves & controller. the price (and reliability) of a taco 007 is so reasonable that i would think you could hook up 3 or 4 zones of those for less cost & complexity than the zoned approach - and even avoid the single pump point of failure possibility. yes, a bit more piping on the return side (but then again, no manifold), but you wouldn't have to worry about about zone priority, long runs, & balancing etc. i gather for a new installation, this is still a choice, but for electrically altering the zone configuration of already installed plumbing, i can see that this would be useful rather than re-piping all over the place.

comments?

Ron Schroeder_2

> The ESP problem of not being able to be used with

> "power stealing" thermostats has been solved in

> the Series 2 model.

>





Tim,

Does this mean that the Series 2 ESP valves draw more power when they are on? What is the opening current and the maintaning current of the Series 1 and Series 2?

Thanks,

Ron

Ron Schroeder_2

> lastly, it occurred to me after

> looking at the prices of the zone valves combined

> with the price of the zone controller (plus

> opportunity for increased possible failures) that

> one might still be better off going the 'lo-tech'

> approach using separate circ pumps for each zone

> and foregoing the valves & controller. the price

> (and reliability) of a taco 007 is so reasonable

> that i would think you could hook up 3 or 4 zones

> of those for less cost & complexity than the

> zoned approach - and even avoid the single pump

> point of failure possibility. yes, a bit more

> piping on the return side (but then again, no

> manifold), but you wouldn't have to worry about

> about zone priority, long runs, & balancing etc.

> i gather for a new installation, this is still a

> choice, but for electrically altering the zone

> configuration of already installed plumbing, i

> can see that this would be useful rather than

> re-piping all over the place.

>

> comments?




I personally have switched from zoning with pumps to zoning with valves since the ESP, Caleffi and a few other under 3 watt zone valves have come out. I did one job where all of the controls, zone valves and pumps draw under 70 watts. The same project zoned with 007's would have had a draw of 1060 watts.

Ron

Unknown

Both Series 1 and 2

have same product specs.

Electrical rating 24 VAC, 60 HZ, 0.29 amps

Power consumption, Charging 3.36 watts, 0.19 amps MAX (LED Flashing)that is a one time thing once it is charged it will not need to do so again.

Power consumption, Power on 1.19 watts, 0.08 amps nominal (LED On)

Heat anticipator setting 0.3