What gauge wire should be used when wiring the PRO TH4210D?
Use 18- to 22-gauge thermostat wire when wiring the thermostat. Shielded cable is not required. You should also plug the wall opening with non-flammable insulation after wiring to prevent drafts from affecting thermostat operation. (Page 6)
Have a follow-up question?
AI-powered answers from the official manual. Verify critical info.
Common questions