Taco ESP Zone Valves

Mark Chaffee

Dear Wall Readers,

There have been numerous posts on The Wall over the last few months regarding the Taco ESP Zone Valve. I wanted to let you know that getting in touch with the people who have posted notes on problems has been very helpful for us here at Taco. It has also allowed us to expeditiously rectify issues surrounding specific jobs.

Because of this feedback from you and other conscious installers we have been able to diagnose symptoms in the field and determine root causes. The most common symptom that has been reported is that the ESP valve would get “stuck” at a position other than where it should be. It might be part open, all the way open without the thermostat calling, partially closed, etc.

Here is why… If you have multiple power stealing thermostats and a corresponding number of Taco ESP zone valves all running off a single transformer, the combined output of the power stealing thermostats transfers enough “noise” into the wiring to give the ESP a false call. The amount and length of the “noise” will determine how far the ESP will turn.

Given this above information we republished the Thermostat Compatibility Reference Guide. I have attached a copy to this posting. If using an ESP Zone Valve we recommend not using a power stealing thermostat. If you must use a power stealing thermostat the thermostat must be isolated from the ESP. The easiest way of doing this is by using a Taco Expandable (-EXP) Zone Valve Control or an Isolated Relay. See the Reference Guide for wiring diagrams.

If you do not know if you have a power stealing or current leaking thermostat… Place an amp meter at the “power” terminals of the ESP zone valve. You should read 0 (zero) amps. Anything but zero and you have a power stealing thermostat.

Thank you very much for your continued usage of Taco products and the ESP Zone valve.

Sincerely,
Mark Chaffee
Taco, Inc.

John Abbott

Conscious?

Mark,
Are you implying that there are UNconscious zone valve installers?

John

Terry_4

Just curious Mark...

What does the EXP have (besides expandability) that the regular zone controller doesn't have?

Robert O'Connor

Wetstock

Mark were you the Taco rep at Wetstock?

Glenn Harrison

Mark,

Thanks for the update and info.

Any word on the compatability of the line of White Rodgers digital thermostats? They are not listed on the updated compatability chart.

Thanks

Glenn Harrison Residential Service Tech

Althoff Industries Inc. Mechanical and Electrical Contractors

Crystal Lake, Illinois

ScottMP

I also

Am interested in the difference between the ZVC and ZVC EXP controls ?

Scott

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

Mark Chaffee

Dave Sweet at Wetstock

That was not me at Wetstock, it was David Sweet. He invented our line of electronic controls under the Sweet Controls brand name before joining Taco about 6 years ago.

-Mark

Mark Chaffee

-EXP vs Standard Zone Valve Control

The difference as it relates to the ESP Zone Valve issue is that all Expandable (-EXP) controls include an isolated relay for each zone.

Other differences include the two PowerPort slots for installation of either a PC600 Post Purge Timer Card, PC605 Priority Protection Card, or the PC610 Universal Timer / Pump Exercise Card. You can also simply plug in our PC700 Boiler Reset Control, PC702 Boiler Reset for Dual Boilers, and our PC705 Variable Speed Injection Mixing Control. The Expandable Zone Valve Control can be expanded to an unlimited amount of zones (the regular is limited to 20 zones).

Both controls include two end switches that are rated to handle line voltage if you want to run circulators off of them and a set of normally open / common / normally closed contacts to run a priority circulator. On a 4 zone Zone Valve Controller you can run four zone valves, two circs, and still control the boiler. It is a very flexible control. If you do not have the Taco electronic controls wiring guide get one from a local wholesaler. Its chock full of 65 pages of creative ways to use our controls to maximize system performance while simplifying the wiring and diagnostics.

- Mark Chaffee

Mark Chaffee

White Rodgers Thermostat

Dear Glenn,
In talking to the folks at White Rodgers the model you are using does not seem to be an issue. However, I am still trying to get my hands on one to do our own testing. I had hoped to have it earlier this week. I will keep you posted. Our local rep is also following up with GW Berkeimer as we planned and I should have info on that soon too.

Did you get a copy of the Taconet yet?

- Mark

Glenn Harrison

Thanks for the update, Mark.

Glad to know progress is being made. Will be VERY interested to know if you find a compatability problem with the W.R. stats and the ESP valves.

And yes, I did get a copy of Taconet, just havn't had time to look at it yet. Thank you very much for that.

Glenn Harrison Residential Service Tech

Althoff Industries Inc. Mechanical and Electrical Contractors

Crystal Lake, Illinois

Steve Ebels

Just had one fail this week

It has been in service for 13 months without a problem. The valve would actuate and rotate to 90 percent of open then stick and be unable to move any further. If you manually moved the valve about 20*s it would then return to closed by itself when the t-stat opened. When the next call for heat came along it would stick in the closed position. After removing the old valve I could see no deformity or burr of any kind on the ball? Why would this thing work for a year and then develope a tight spot?

What did the Taco guy tell you Chuck?