Nest to turning radiant zone off completely

[Basalt]

I have a radiant system that uses taco valve  controllers. The zones at times do not fully shut off and I have to cycle them to fully shut off. It uses the red and white wires.

Anyone else have this issue?

Regards,

Bobby

[Basalt]

They nest does not give me a power supply error.

[CoolingWizard]

Usually TACO water valves are controlled by separate control system, and the thermostat simply notifies the control system to either open or close the valve. Now there are two types of valves out there. those that need power to open and use a spring to close, and those which need power to open and power to close. 

The AC Cooling Wizard

[Patrick_Caezza]

@Basalt 

Is a Taco Zone Valve Controller installed, or are the Valves being directly controlled by the Thermostat?

If there is a Taco Zone Valve Controller, can you post a picture of how it's wired?

If the valves are controlled directly by the thermostat, can you post a picture of them and how they are wired? The valve model number and manufacturer information too.

You might need to add a relay for directly controlled valves, and the thermostat might not have enough power to operate them fully.

[Basalt]

@Patrick_Caezza @CoolingWizard 

I believe it is run by a controller that has a red and white wire that links all of the valves.

Regards,

Bobby

[Basalt]

White wire goes from controller to the thermostats Daisy changed along and the red goes to first valve and thermostat and Daisy changed to the next valve if that makes sense..

@Patrick_Caezza @CoolingWizard 

[CoolingWizard]

How many water valves are in the system? Typically the boiler has a water makeup valve, main controller, then there are manual or electrical water valves to supply the hot water to the radiators. Additionally there are water circulating pumps that also get turned on. These water valves tend to be 24 VAC controlled and the circulating pumps are 120VAC.  Depending on the boiler, there is often multiple transformers because the Volt Amps can exceed the typical 40VA of the HVAC system transformer. Can you snap a picture of your boiler arrangement and share it with us?

AC Cooling Wizard 

[Basalt]

@CoolingWizard 

Thank you for all the help!!

 

@CoolingWizard 

[Patrick_Caezza]

@Basalt 

You don't have a zone controller installed (i.e., Taco). Each valve is wired directly to each thermostat.

If you look at page three of the attached instruction sheet, you'll see how your system is basically wired.

What is needed is power for each thermostat and since there are only two wires going to each thermostat you will most likely need a Google Nest Power Connector installed for each thermostat wired like this. You can use a single 24Vac transformer for all of the thermostats and you might even be able to use the current 24Vac transformer.

Use this wiring if you add a transformer.

Use this wiring if you uise the 24Vac transformer alreadly installed. Ignore the dashed line for the G terminal.

[CoolingWizard]

OK let’s see if I can help you understand your system a little bit. If you look closely you and I know you see it already the taco electric control water valve has two screw terminals on the left side of two screw terminals on the right side. The two on the right side are wired to the boiler controller. The two on the left side Typically go to the thermostat as R and W. So in your home, you have multiple zone thermostats, controlling these water zone valves. You can see the thermostat control cable going into the hole in the backboard. So do you have multiple thermostats ie., one in each room?

The AC Cooling Wizard

[Basalt]

@CoolingWizard 

Yes we have multiple thermostats and the wires that go into the chip board run to those.

[Basalt]

Gracias!

[CoolingWizard]

Yes indeed, hopefully a power common is ant each thermostat, right? If the cable going into the chipboard has three conductors, we just need to connect the third wire to the common (white wire) side of the valve. When the valves do not close, it can be caused by a bad capacitor or a failing motor.  The LED has a flash sequence to indicate and problem.  The post by @Patrick_Caezza  has an error chart you compare with. Look for an LED flash sequence for a valve that did not close completely next time. 

AC Cooling Wizard

[Basalt]

@CoolingWizard @Patrick_Caezza 

Okay, will try to check tomorrow. They were both working perfectly until I installed the Nests to two of the zones.

[Patrick_Caezza]

@Basalt 

Ah, that makes sense.

If everything worked correctly until you added two more thermostats, you exceeded the system power capability. To fix this problem, you must install a bigger transformer or split the system to work off of two separate transformers. If the current 24Vac transformer is rated at 40VA, you should replace it with a 60VA one, or you could add another 40VA transformer and change the wiring to split the valves and thermostats between them equally.

[Jake]

Hey Basalt,

I wanted to check in and see if you are still in need of any help. Please let me know, as I would be happy to assist, and answer any questions you may have.

Best regards,
Jake

[Markjosephp]

Hi Basalt,

It has been a few days since your last reply, and we're going to lock the thread within 24 hours. If you have any questions, please feel free to create a new post.

Regards,

Mark

[Jeran]

Thank you for helping out on this thread, CoolingWizard and Patrick_Caezza!

Hey there Basalt,

I'm just checking up on this thread, do you have any more questions or need any additional help? 

Best regards,
Jeran

[Basalt]

I have been so busy I haven’t had a chance to check. Both nests locations have two additional  wires in the casising that I could use. Should I try to add a transsformer buy using the additional wires?

[EmersonB]

Hi Basalt,

Thanks for getting back to us. Upgrading or adding a transformer depends on your boiler. What additional wires are you referring to? If possible, could you share here the photo of those additional wires on your Nest Thermostat? Looking forward to your response.

Best,

Emerson

[EmersonB]

Hello Basalt,

I'm dropping by to ensure that everything is covered here. How's it going with your Nest Thermostat? We would appreciate it if you could share the information I’m asking above. We'd be glad to hear from you.

Regards, 
Emerson

[EmersonB]

Hey Basalt,

Just one final check in here since activity has slowed down. We'll be locking the thread in the next 24 hours, but if you still need help, we would be happy to keep it open. If there's more we can do, just let us know.

Thanks, 

Emerson