# One heating zone not working



## RonDIY (Oct 23, 2010)

Hi all,
I have a gas fired furnace with 8 zones. Three zones are radiant floor heating. Five zones are baseboard. My problem lies with just one of the baseboard zones.
The 5 zone baseboards are controlled by 2 newer Uponor Valve Actuators and 3 older Wirsbo Valve Actuators, similar to A3020522 but say A 4024F NC on them. All are 4 wire 12V. When one of the zones with the older Wirsbo calls for heat I can see that the valve opens, but the furnace and pump do not kick on.
My question is this, Does the valve actuators control turning on the furnace/pump? Is that what I have to replace? Or is the problem with the controller board? I have an Argo AR861-3II control board. To be honest I don’t know if the Argo is for the baseboard zones, or the radiant heat zones, or both.
The fact that the room thermostat is opening and closing the valve leads me to believe the thermostat is okay, but I don’t know for sure. 
Let me know if you need additional details. Thank you.


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## beenthere (Oct 11, 2008)

How many wires on the actuator.


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## RonDIY (Oct 23, 2010)

All are 4 wire, 12V


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## beenthere (Oct 11, 2008)

Good chance that 2 of those wires are to tell the circ to run. weather through the zone panel, or other control, can't say from here.

Use a meter and see if 2 of those wires are from an end switch.


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## RonDIY (Oct 23, 2010)

@beenthere
I appreciate your taking the time. My knowledge of wiring is limited. I do have a meter, but don’t know what an end switch is or how I go about testing if the wires are from it. Can you provide some guidance for me?


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## beenthere (Oct 11, 2008)

And end switch is just a switch in the actuator.


use your meter on its ohm setting. An open end switch will have infinite resistance. The wires that go to the actuators motor, will have a resistance to them. So you will know thats not the wires to the end switch.


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## RonDIY (Oct 23, 2010)

Okay, I will try that. Dumb question: do I disconnect the wires before testing them? Also, each actuator has two yellow and two orange wires. Do I only test the like colors together?
Thank you for your patience.


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## beenthere (Oct 11, 2008)

Same colors.

Yellow are probably the switch wires.


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## RonDIY (Oct 23, 2010)

I disconnected the two yellow wires and tested. Got a reading of 22.6 ohms. That means they are not connected to an end switch?
I also tried the orange wires, but the readout kept fluctuating between zero (or very low) and 18k.
So what does all this mean??


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## beenthere (Oct 11, 2008)

Check the wires that came to the actuator. Turn up the thermostat. See if the ones that went to the yellow wires have 24 volts. If so, then the orange is the switch, and you have bad contacts in it. Need new switch.


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## RonDIY (Oct 23, 2010)

I turned up the thermostat. I'm getting a reading of 26.2 volts on the yellow wires. I also tested for voltage on the orange wires. Getting a reading of 27.8 volts on the orange wires. (Sorry, I re-checked, they are rated 24V not 12V) Should I be getting voltage on both? Is the slightly higher voltage damaging?
Just to clarify... is the end switch you were referring to in the actuator or in the control board?


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## beenthere (Oct 11, 2008)

In the actuator.

Turn your thermostat to off, or all the way down, so its not calling for heat. the wire set that no longer has voltage, will be from the stat.

Up to 30 volts is ok.


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## RonDIY (Oct 23, 2010)

The yellow wires no longer have voltage after I turn the stat down. The orange still do.

I did some further reseaech and found this technical bulletin on the actuator:
http://www.uponor-usa.com/~/media/F...otorizedValveActuator_TB_9_06.aspx?sc_lang=en
The only difference is that mine say Wirsbo, I think they're the same company.
Based on the diagram on page 1, there is an end switch connected to orange (red) wires. The yellow are to the motor.
It also says these are for radiant heating systems, but these are controlling my baseboard heat.

So, is it the end switch that is supposed to send the signal to the furnace and pump to turn on/off? Will replacing the valve actuator solve the problem?


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## beenthere (Oct 11, 2008)

Yes. The end switch closes to complete the circuit to enable the boiler and circ to run.

Replacing it should solve the problem.


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## AllanJ (Nov 24, 2007)

Always turn off the power to the circuit before using an ohmmeter or continuity meter.

Generally ohms (or continuity) is not reliably measured by just touching the meter probes anywhere. At least one of the two leads to which the meter probes are touched must be manually disconnected from the rest of the circuit during the test. Or if you are testing a device via a screw terminal, take the wire off the terminal before touching the test probe.

To do ohms testing at a bunch of wires, take the bunch apart and touch the probe to just one wire at a time. (Label the wires so you can reassemble them correctly.)

(To measure voltage, leave the power on.)

If another zone is calling for heat and has the pump and furnace running, does the zone in question heat up?

How many wires does the thermostat have? A two wire thermostat is working okay if it turns the valve on even if the pump does not come on; the problem is elsewhere.

When measuring voltage at the thermostat, first find out which pair of wires goes to which internal switch of the thermostat (if more than 2 wires altogether). You will measure voltage when the thermostat is not calling for heat (or air conditioning) and you will measure zero when the thermostat is calling for heat. Some thermostats must be level to call for heat at the temperature setting shown on the dial.


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## RonDIY (Oct 23, 2010)

#allanj
The stat does triger the valve to open, but something is not triggering the furnace to kick on. And yes, the problem zone will get heat if a call for heat is triggered from another zone. Thanks for sharing info on meter testing. Very helpful.

#beenthere
Based on everything said, I believe your conclusion is correct - I need to replace the valve accuator. That's good news since it's something I can do myself and save big $$ on a service call. Thank you so much for all your help and patience with me.


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## beenthere (Oct 11, 2008)

You bill is in the mail. :laughing: J/K

No problem, your welcome.


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