Thermostats

[Irv]

I have a EWC Ultra-zone panel installed 11/02
EWC-ST-3D with 3 working zones
Zone 1 is controlled by a White Rodgers 1F-80-51 programmable thermo for heat and A/C, and is working fine.
The other 2 zones have Mercury switch thermos that aren't programmable.
Which programmable Thermostats can I get that will be compatible with my system. Zones 2 + 3 have 3 wires each, White, Yellow and Red.
Thank you for your help

[Erik W.]

You can use the EWT-3707 or a honeywell pro 4000 th4110d