How to trouble shoot zone valve problem

Al_18

2 zone hot water system with baseboards ,first floor zone will demand heat but system doesn't respond. If I go down and hit the zone valve,the system fires up and all's well. I measured voltage on the 24v DC zone valve,it's OK. Can the zone valve stick,is that possible ? I plan to replace the valve,does that sound right?
Thanks
Al

Mark Walnicki_2

What kind of zone valve?

My guess is the zone valve has actually opened, and it's the end switch that needs that little extra persusion to "make" and signal the boiler/circulator.

For the heck of it, before you replace anything, I would check and double-check all your low voltage wiring. Are all connections tight? I've seen connections that *look* okay, but are barely hanging on by a thread! That could cause the problem you describe, as well.

curiousity kills

zone valve

DC?????It should be 24 vlt ac.is this a 3 wire taco? If so test on a call for heat for 24 vlt at term 1 and 2.If you have voltage there and the zone doesnt run the tsat is good but the head is not. Then try jumpering 2 and 3 and the zone should run but the head still is no good

jim lockard

in the zone

yes sure zone valves can stick. Al depending on brand they sell rebuild kits for zone valves.
Are all electrical connections clean and tight ? should be 24 volts AC, you can connect 24 volt light bulbs across the contacts to show when voltage is being applied. BEst Wishes J.Lockard

Unknown

Some Auto Mag zone valves

are DC voltage and they do stick. Is that what you have? Let us know what make you have and we can help you.

Al_18

Electro Zone 24v dc

the system is 30 years old,probably needs to be replaced

Unknown

Al, I will look that one

up tomorrow as I do not have the zone valve book handy here at this location. I will post what I can find if anything.

Unknown

Well how about that

I found it in my old zone valve book. That is an old one. I can e-mail you the little bit of info I have on them just e-mail me at gastc@cox.net.

The Models I have limited info on are the RB-4 and RB-6 which uses a 60 VA transformer with a built in rectifier to convert to 20 volts DC. It looks like when the thermostat calls it just powers the zone valve which opens. At the same time it closes a switching relay in the Electro Zone Box. the zone valve does not have an end switch.

Al_18

YES...that's it

the relay kicks in and starts the circulating pump....sometimes I have to hit the zone valve to get the system to operate..I plan to replace the valve

Al_18

Thanks for your help

Thanks to all for taking the time to help me out
Al

helpingothershelpthemselves_2

ElectroZone was used alot on Hydrotherm millivolt gas boilers near thirty years ago . Here on Long Island we still see them in some areas.
Be aware not to replace the existing 24v DC zone valve with a 24v AC zone valve unless you plan on replacing the entire controller as well. The ElectroZone controller converted ac to dc for zone valve operation by means of a 60 VA transformer and rectifier .The 24v DC zone valves did not have end switches . We have found that most problems occured because of dirty contacts on the controller.

We on Long Island discuss this in our local BOCES (for our students), because we still have them in operation on our lovely Island .

Hope this helps you .
Ken Resnick

L.A. Wilson Technological Center
Western Suffolk Boces

heattech@optonline.net

Al_18

Thanks to All

Replaced the coil in the zone valave,existing coil was burnt to a crisp. Thanks again for all your help
Al

Joe Mattiello

Taco, 570 series

You never mentioned the manufacturer of the valve, but if it's a Taco, you might find the troubleshooting guide I attached useful.
Taco, Inc.
Joe Mattiello
Technical Service Technician
joemat@taco-hvac.com
401-942-8000 X 484
www.taco-hvac.com