Upgrade EWC ST-2D to BMPlus3000 w Programmable Stat

[rfanti]

I currently am using a ST-2D split zone with forced hot air and A/C. My thermostats are wired as:

Master (1st floor)
R - red
O - orange/red
B - blue
W - white
G - green
Y - yellow

Secondary (2nd floor)
R - red
Y - black
W - yellow
G - green

I have no C or X wire to power a programmable thermostat. If I upgrade the panel to a BMPlus3000 panel (for future furnace A/C 2 stage upgrades down the road), how can I use a stat that requires a C wire (like Nest or Venstar 5800) without adding a wire?

Thanks for your assistance,
Bob

[Pcyrana]

Bob,

You can abandon the "G" wire and use the G wire for the Common.
This will eliminate the ability to control fan only operation but that will not affect your system when you call for heat or cool.
If you have any questions please let me know.

[rfanti]

Thanks Patrick,
Does the G wire have a constant 24v running through or just when the fan is activated?

Bob

[Pcyrana]

You will have to move the "G" wire to the C terminal on both the zone panel and the thermostat.
You will have no wire connected to the G terminal anymore.

[rfanti]

I understand that now, use the G wire as your new C wire everywhere.

The ST-2D panel has a R connection (bottom right) however the BMPlus 3000 panel (system) has no such letter connection.

What do I do with the R (red) wire?

Thanks,
Bob

[Pcyrana]

Bob are you referring to the system terminal block in the bottom left hand corner of the board?
If so, the BMPlu3000 has RC and RH terminals. The red wire will connect to either of these terminals.

[rfanti]

Yes, its the lower left corner I was talking about. Starting to make sense.

Thanks Patrick!

Bob