System 2000 and modern thermostats - help needed with power and "C" wire

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Old 02-04-14, 12:58 PM
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System 2000 and modern thermostats - help needed with power and "C" wire

I have a System 2000 and had Nests installed. I found they were glitchy and kept the System 2000 heating lights flickering, so I had to remove them. There is supposedly an issue with Nests and System 2000. So, I went out and bought Honeywell Wifi thermostats (RTH-9580WF). I hooked them up for all 4 zones. They each need a "C" wire. I have an open third wire to each thermostat and connected the third wire as the "C" wire to the System 2000 transformer hot side. The thermostats did not start up (one turned on and off, cycling indefinitely). I hooked up a separate transformer to an open junction box and ran power to each thermostat successfully. The problem is that effectively hotwires the thermostats to continuously call for heat.

Has anyone successfully added multiple Nests or Wifi thermostats to a System 2000? Or does anyone have suggestions for how to set up a relay for each?

Thanks in advance. System 2000 seems great and efficient, but is no fun to get you into the 21st century.
 
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Old 02-04-14, 03:59 PM
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I have an open third wire to each thermostat and connected the third wire as the "C" wire to the System 2000 transformer hot side.
If you did indeed connect to the 'hot side', then that would seem to be the mistake.

The " C " wire is a 'COMMON', the 'HOT' already ran to the thermostat on the 'R' terminal.

There is probably more to the story though... for example:

You have FOUR ZONES. How are those four zones being controlled? Electric zone valves, or individual pumps for each zone?

Explain a bit more about the setup and we can help...
 
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Old 02-05-14, 06:34 AM
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Zone valves are set up for each zone. I may be misnaming the "hot" wire, but I essentially hotwired each thermostat to constantly call for heat, connecting the white wire to my third open wire on the four thermostats. Someone told me I need some sort of relay, but not sure how that would work.
 
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Old 02-05-14, 07:31 AM
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Still not enough info, and what you have said is confusing to me...

What make and model are your zone valves?

Is there a separate transformer that powers the ZONE VALVES?

Are the thermostats all for HEAT ONLY?

Are the zone valves wired to a CONTROL PANEL, or are individual wires running between them?

It is unlikely that you require a relay, unless the existing zone valves are of a type knows as THREE WIRE. In this case your existing thermostats would have been 'special' for this purpose, and in order to use other thermostats a relay MAY be needed... but I can't know this until you tell me what valves you have, how they are wired, etc.

Remember, no two systems are the same... I need ALL the details in order to be able to help you.
 
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Old 02-10-14, 12:04 PM
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Not sure about the Wifi thermostats, but Nests will work very well with System 2000 with the simple addition of a resistor between terminal A2 and Tx (x is the input zone number) Each zone with a Nest requires its own resistor. You need 200 ohm 15W for which you'll have to Google a mail order electronics supplier. Radio Shack does not have this one. Make sure you keep the resistors away from anything plastic because they will get hot.
 
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