Zone valve clicking

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Researcher2

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I have a hydronic system with a single zone valve with an air handler in a condo. The 2004 / original actuator head (TACO model ESP075c2-2) wouldn’t close all the way. I spoke with TACO support and they said this is common and the capacitor fails over time and can no longer close.

They no longer make this model, but the replacement is TACO model Z075C2-2. I ordered this unit back in May and it opens and closes all the way.

Unfortunately, the transformer or relay (inside our air handler) makes a clicking sound with the new model when charging the actuator to open the valve. It doesn’t matter if the actuator is on or off the ball valve or hanging in my hand. In other words it is not a friction issue with the ball valve

When I hook up the old unit the clicking sound goes away.

I have been working with TACO support for several weeks. They suggested I add 1000 ohm / .5 watt resistor see picture. This didn’t stop the clicking noise.

Now TACO support is suggesting “If you tried the resistor and the relay is still clicking you may have to wire in a separate transformer to power the zone valve.”

I have tried contacting all of the HVAC companies near me and none of them work on hydronic systems. Just forced air. And I have a feeling that this might also not work.

Does anyone have experience with this? Or have any ideas on how best to resolve?
 

Reach4

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What voltage is across the old unit and the new unit when you go to actuate the valve? I think that is going to be AC volts.
 

Researcher2

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Brand and model of the thermostat for that zone. Heat antisipator should be set at .5 amp.
Hi @Fitter30

Thanks for the advice. I have an Ecobee 4 thermostat.

Is there a setting to change the heat anticipator on an Ecobee thermostat?

I looked in advanced settings and google, but I didn't see any way to modify the heat anticipator setting.
 

WorthFlorida

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Smart digital thermostats do not have an anticipator setting, at least I have never seen any.

Transformers do not make a click sound so it is a relay. Just about anything to do with HVAC runs on 24v AC. What is the air handler model? The thermostat takes 24 volts from the red wire and when it calls for heat it puts the 24v on the white wire (or W2 if it is the second stage heat). You'll need to find exactly which relay is make the noise or opening up the circuit.

I'm thinking the thermostat operates a relay in which its contacts send 24v (from another transformer) to the zone valve. The voltage/current required through the thermostat to operate a zone valve may not be high enough so a relay is needed to get the right voltage and current to operate the zone valve. Old mechanical thermostat's would not have a problem but all digital thermostats use a micro relays or a sold state switch.

The zone valve only draws .48amp at 24v which is very small. To test remove the thermostat from the base plate and short the red wire to the white wire. (R terminal to the W terminal). Heat should turn on and the circulator pump and zone valves should be working. If you still hearing clicking then it seems to be a bad relay. If it all works then the thermostat may not be able to switch the full voltage and current needed (which is doubtful). The link to the picture only displays a blank page. Relay's can go out of intolerance. For this type of troubleshooting, a volt-ohm meter is needed.
 

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Smart digital thermostats do not have an anticipator setting, at least I have never seen any.

Transformers do not make a click sound so it is a relay. Just about anything to do with HVAC runs on 24v AC. What is the air handler model? The thermostat takes 24 volts from the red wire and when it calls for heat it puts the 24v on the white wire (or W2 if it is the second stage heat). You'll need to find exactly which relay is make the noise or opening up the circuit.

I'm thinking the thermostat operates a relay in which its contacts send 24v (from another transformer) to the zone valve. The voltage/current required through the thermostat to operate a zone valve may not be high enough so a relay is needed to get the right voltage and current to operate the zone valve. Old mechanical thermostat's would not have a problem but all digital thermostats use a micro relays or a sold state switch.

The zone valve only draws .48amp at 24v which is very small. To test remove the thermostat from the base plate and short the red wire to the white wire. (R terminal to the W terminal). Heat should turn on and the circulator pump and zone valves should be working. If you still hearing clicking then it seems to be a bad relay. If it all works then the thermostat may not be able to switch the full voltage and current needed (which is doubtful). The link to the picture only displays a blank page. Relay's can go out of intolerance. For this type of troubleshooting, a volt-ohm meter is needed.
Hi @WorthFlorida

Thanks for your reply.

Air Handler Model = 24VDX-3HH - made by First Co. See attached screenshot.

Since the old actuator works without causing a clicking noise (see attached zipped noise file from new actuator) and I just noticed the actuator MFG (TACO) also sells an optional power stealing resistor. Previously, tech support told me to order a 1000 ohm / .5 watt resistor (picture attached) it seems like they are aware of an issue with the actuators drawing too much power.

I ordered this resistor from Amazon. I supposed I could order the TACO version if you think it might help? I would have ordered the TACO resistor before if I knew it existed.

TACO tech support said: "The capacitors in the zone sentry are larger the the old style actuators, which could result in a larger draw when charging. Is the actuator connected directly to the thermostat and a transformer or is there a control being used? What size transformer is being used?"

My response "No separate control that I can locate. See attached pictures. I also contacted the air handler mfg (First Co) for the transformer specs and they said "Standard transformer 240/24v - 40va"

TACO tech support: "It appears that the power draw on that transformer is right on the hairy edge with everything on that transformer. The resistor may alleviate the issue when the zone valve is charging and the ECO-BEE does draw a lot of power also." and later... "If you tried the resistor and the relay is still clicking you may have to wire in a separate transformer to power the zone valve."

This leads me to believe (likely foolishly) that...

1. My current equipment is not broken (yet) and that the solution involves a different or additional transformer / relay if I want to use the existing actuator valve. I do wish TACO would come out with a revision to their actuator that doesn't draw so much power. Maybe I should try find an hire an HVAC tech to add a transformer?

2. Another possible solution might be to replace the entire valve body with a different actuator mfg (Honeywell?), but they might have similar or different issue. This also requires a water pipe cut. There are shutoff valves so hopefully it won't impact the entire condo building.

3. Or hopefully there is a third and much better (hopefully easier) option that I am not aware of?

Lastly, I believe this issue will affect all of the 70+ units in the condo building and would be good to have a viable (and hopefully simple) solution for all residents.

Attachments:
1. Actuator with resistor added (this is from TACO support) as possible solution to reduce power draw
2. Relay or Transformer inside of air handler
3. Air Handler Model Information
4. Audio file with clicking noise (had to zip file as audio files are not allowed as attachments)
5. Wiring diagram inside of air handler
6. Full shot of inside of air handler (showing relay / transformer, wiring diagram, etc)
 

Attachments

  • Actuator with resistor from TACO support.png
    Actuator with resistor from TACO support.png
    365.6 KB · Views: 13
  • Relay or Transformer inside of air handler.png
    Relay or Transformer inside of air handler.png
    818.8 KB · Views: 11
  • FirstCo Model.png
    FirstCo Model.png
    724.5 KB · Views: 11
  • Taco zone valve causing noise.m4a.zip
    106.5 KB · Views: 8
  • Wiring Diagram Inside Air Handler.png
    Wiring Diagram Inside Air Handler.png
    572.8 KB · Views: 10
  • Inside of Air Handler.png
    Inside of Air Handler.png
    828 KB · Views: 10

Researcher2

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What voltage is across the old unit and the new unit when you go to actuate the valve? I think that is going to be AC volts.
Hi @Reach4

Thanks for the help. I can try to capture this later. I am bit concerned about continuing to test with new unit and loud clicking noise.

Will this damage the relay / transformer?

Also, does my latest post with the pictures and details help?
 

Fitter30

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Relay operates the fan only according to the diagram. Don't see the relay just the.transformer. Might be behind be behind the transformer but don't think theres enough room in that juction box. Ecobee 4 thermostat do you have it wired and programed? Wired conventional heat & cooling electric heat?
 

WorthFlorida

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Until it is known what this clicking noise is it hard to say what the problem is. From pictures the resistor is in parallel to the coil of the actuator. That decreases resistance and increases current. A resistor in series with the load increases resistance and decreases current.
At the relay and transformer assembly, the one relay is to control the fan motor (G wire). The relay will close and open if the voltage drops is too low.
As Reach4 suggest, do get a reading of the voltage across the connection at the actuator for both the old and new. In addition when you try it with the resistor. The new actuator draws .48 amps at 24v AC. Do you know what the existing actuator draws?
 

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Relay operates the fan only according to the diagram. Don't see the relay just the.transformer. Might be behind be behind the transformer but don't think theres enough room in that juction box. Ecobee 4 thermostat do you have it wired and programed? Wired conventional heat & cooling electric heat?
Hi @Fitter30

Thank you for the help.

Yes, the Ecobee is wired and programmed. I have had the Ecobee 4 for approximately 4 years with no issues. It still works with the old TACO actuator and no clicking noise.

I'm sorry, but I'm not sure I understand what you mean by "wired conventional heat and & cooling electric heat?" I can send a picture of the wiring behind the Ecobee thermostat if that would help.

When I purchased the Ecobee (back in 2018) I followed the Ecobee instructions, but my memory isn't as good as it used to be .. :)
 

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Until it is known what this clicking noise is it hard to say what the problem is. From pictures the resistor is in parallel to the coil of the actuator. That decreases resistance and increases current. A resistor in series with the load increases resistance and decreases current.
At the relay and transformer assembly, the one relay is to control the fan motor (G wire). The relay will close and open if the voltage drops is too low.
As Reach4 suggest, do get a reading of the voltage across the connection at the actuator for both the old and new. In addition when you try it with the resistor. The new actuator draws .48 amps at 24v AC. Do you know what the existing actuator draws?
Hi @WorthFlorida

Thanks for your help.

Old / Current Actuator (no noise): Model E075C2-2
Power Consumption, Charging: 12.84 Watts, 0.54 Amps Max
Power Consumption, Power On: 1.44 Watts, 0.06 Amps Max
Source Link & Source Instruction Manual

New Actuator (with clicking noise): Model Z075C2-2
Power Consumption, Charging: 11.4 Watts, 0.48 Amps
Power Consumption, Power On: 1.44 Watts, 0.06 Amps
Source Link & Source Instruction Manual

According TACO specs it looks like the new actuator draws less power so that conflicts with what TACO tech support has stated -- "The capacitors in the zone sentry are larger the the old style actuators, which could result in a larger draw when charging."
 

Fitter30

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Eco stat doesn't show hot water air handler. Only thing they show that would work is electric furnace and cooling. Where G and W are energize on a call for heat
 

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Eco stat doesn't show hot water air handler. Only thing they show that would work is electric furnace and cooling. Where G and W are energize on a call for heat
Hi @Fitter30

It's been a few years, but I think I wired like a regular furnace. When Ecobee calls for heat it charges / opens the actuator (allowing hot water in) and turns on blower.

Ecobee Wiring.png
 
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WorthFlorida

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The specs reads 6 seconds from fully open to close, 4 seconds from fully closed to open.

Now the use of a capacitor makes sense. With a capacitor voltage slowly drops to allow the motor to close the valve since any controller immediately removes power to the actuator. Doubtful that the transformer is short on power. The spec reads 12 zone valves/40VA transformer.

Thermostat wiring is a little strange. Is this the unit you're testing with? Is there 4 or 5 wires? W! is heat and that shout be wired to the actuator. ACC+ is 24v to drive accessories and that is strapped to W1 if this is four wire. Anytime a call for heat or cool, voltage is applied to ACC+. The white seems to loop around or are there 2 white wires. Also, two reds? Is the thermostat near the air-handler so it is easy to run a second wire? I know everything works as is ,I'm just trying to learn things here.
 

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The specs reads 6 seconds from fully open to close, 4 seconds from fully closed to open.

Now the use of a capacitor makes sense. With a capacitor voltage slowly drops to allow the motor to close the valve since any controller immediately removes power to the actuator. Doubtful that the transformer is short on power. The spec reads 12 zone valves/40VA transformer.

Thermostat wiring is a little strange. Is this the unit you're testing with? Is there 4 or 5 wires? W! is heat and that shout be wired to the actuator. ACC+ is 24v to drive accessories and that is strapped to W1 if this is four wire. Anytime a call for heat or cool, voltage is applied to ACC+. The white seems to loop around or are there 2 white wires. Also, two reds? Is the thermostat near the air-handler so it is easy to run a second wire? I know everything works as is ,I'm just trying to learn things here.
That is the thermostat that has been in place for over 4 years and still works perfectly with the original actuator.

There is a conduit from the closet to the thermostat. I had to run extra wires for the ecobee.
 
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