Thermostat Options for EWC-ST Series Control Panels

[TTJJJJ]

Have there been any new thermostats coming on the market since Dec 2010 (when this thread started) that work with the 2t-2c zone controller? I am looking for a 7 day progrmmable. I do not know where to buy the EWC brand t-stat around here (48348). What about the honeywell RTH7600D? It have 6-wire apability but the O does not seem to be an option. Would this t-stat work as the zone 1 controller though?
Thanks,
Tim

[Pcyrana]

Tim,
The White Rodgers 1F95-1271 and 1F97-1277 are two thermostats that are 7 day programmable and will work on the Zone 1 of the ST series panels.
The RTH7600D will not work because it does not have a separate "O" and separate "B" terminal.

[TTJJJJ]

Ah bummer! Thanks fo rthe quick reply Pcyrana.

It stinks because I just went out and bought the Honeywell this AM to try out. I was thinking it would work based on the wiring diagrams of the honeywell vs. the ST controller. The ST controller zone 1 wiring diagrams shows the O terminal as connected to the RC/O so I figured I could connect this to the RC terminal on the T-stat.

Also, on the T-stat diagram it lists the C1 terminal as C1 or X or B, so I figured I could hook up the B to this one.

See the attachment for my proposed wiring diagram? Are you sure this wouldn't work?



Many thanks,

Tim

[Pcyrana]

No Sir unfortunately that thermostat will not work for you. The master thermostat requires a separate "O" and separate "B" terminal.
The way you have it wired in that diagram, the "O" will always be energized and the board will never allow a call for heat.

[TTJJJJ]

Alright cool. Thanks for clarifying that.

The more I look into this, and looking at the cost of the thermostats, I'm thinking of upgrading the board to the BMPlus3000. this would let me hook up my 3rd zone (right now 2 of my zones are hooked to the same stat) and would also allow me to get full use out of a 2 stage furnace plus a 2 stage AC unit when it is time to replace them. Also, i can use the cheaper Honeywell 7 day programmable stats.

I just need to make sure my old actuators are compatible with the new board.

Thanks for all the help!

Tim

[Pcyrana]

EWC's newer model zone panels will work with any of our older model actuators.

[KittyHawkDunes]

Along the same line... I have an EWC-ST-2C with two damper valves, heating and A/C. I am looking to wire an RTH6400 series Honeywell Thermostat. The new stat has G, W (O/B), Y, R, and Rc terminals. Can I wire O and B together. No heat pump, just boiler and A/C with air handler.

[Pcyrana]

No unfortunately that thermostat will not work with the ST series zone Panel. The master thermostat requires a separate "O" and separate "B" terminal. A combined O/B terminal is not suitable.

[JBogon]

I thought I read somewhere the thermostat "C" terminal can be used for the "B" wire and then the "O/B" terminal can be used for the "O" wire in Zone 1. Anyone know if this is true?

[Pcyrana]

This is not true.
The manufacturers GE, York and Trane use the B terminal as a common or "C".
I'm assuming that is what you are referring to.
This is not the same as the separate B terminal required for the ST panels.