Troubleshooting Zone Valve

PastorMike

I have 3 zones in my house. Basement and 2nd Floor are fine, but as of today I can only get heat on the 1st Floor if I manually open the zone valve.

As far as I can tell, I've got one of two problems (1) either the valve has gone bad (2) or it's not getting enough voltage.

Here's my problem. I have a multimeter to test the voltage, but I'm not getting a reading from any of the 3 zone valves even with them on. I assume I'm using the tool wrong, but I don't have a clue what I'm messing up. I have it set to read up to 200V and I'm connecting the leads to the first two screws on the zone valve. My father-in-law electrician who gave me the multimeter earlier today, tested it , so I know it's not the problem. Any thoughts?

Thanks in advance.

Snowmelt

Here's what I did one time when I had to test 4 zone valves and it was a hug mess. I went to the supply house bought a taco 4 zone board, spent a little time hooking it up. Charged the home owner for the board. Then trouble shot the bad zone and showed the customer the new board. I showed him that he can trouble shot what zone or thermostat wasn't working in future. I got paid, he got a easy to read no spaghetti mess zone system.

BobC

Is that meter set to read AC volts?

Bob

icesailor

You didn't say what kind of valve it is. If it is a Taco with three wires in a row, the top and the middle wires have the power. 24 +/- volts. You have to take the #1 wire off the screw and test it to #2 middle wire. If you notice a faint spark, the head is bad. If it is a Taco zone valve, replace the power head. The coil is bad or the wax ran out of the cylinder.

IMO, you don't need to install a Zone Valve Control board. They came in to play because so many Sparky's had a hard time figuring out how to wire zone valves. Especially if there were more than 3 zone valves and you needed bigger transformers.

Common problem, easy fix.

You can also open/pull down the lever on the bad valve and leave it open. Whenever another zone calls, it will operate both the good zone and the bad zone. Until you get a new Power Head. If the valve/zone doesn't stop heating when the other zone is done, close the lever on the valve head.

billtwocase

I will agree with Ice. The panel relays may make the wiring look pretty, and easier, but they are usually nothing more than a light show, and are not a cure all, as they fail too. Start at the thermostat, and work your way to the stepdown, and then terminal #1 and #2. Was there resistance when you manually opened the zone? May also be a bad end switch

PastorMike

Bob - It was definitely set to measure DC.

icesailor - Yes, it is a Taco with three wires in a row. I was under the impression that I could test the voltage without unscrewing anything. As of now replacing the power head is the plan.

Thanks.

hot_rod

Have your father in law come along with the meter

Seriously, it's not the meter, it's the person holding it that the key to troubleshooting.

Zman

Boiler controls are 24 volt AC.

icesailor

PastorMike said:

Bob - It was definitely set to measure DC.

icesailor - Yes, it is a Taco with three wires in a row. I was under the impression that I could test the voltage without unscrewing anything. As of now replacing the power head is the plan.

Thanks.

The voltage is AC.

With the terminals connected, and the thermostat calling, you are only reading a wire with voltage but no place to go. If you put a meter across the two terminals on a T87 round thermostat and the thermostat isn't calling, you get 24 +/- volts. When you close the thermostat/Make it call, the voltage goes to zero because you only have 24 volts in the line with no place to go. Its got to hook up with the other side of the transformer to go to the dance.

Tim McElwain

With the thermostat calling, your meter set on AC scale, you should have power at terminals #1 and #2 on the TACO ZV. If you have power and the valve will not open replace the zone valve head.

icesailor

Tim McElwain said:

With the thermostat calling, your meter set on AC scale, you should have power at terminals #1 and #2 on the TACO ZV. If you have power and the valve will not open replace the zone valve head.

Absolutely right. Being ADD, Dyslexic, and mentally disturbed, I always forget the procedure for checking the valve head because I am always alone. Just going upstairs and turning up the thermostat, I will go back downstairs and forget if I turned it up or down.