Honeywell CT2700 Owner's Manual - Page 3
Three Thermostat Wires - programmable thermostat
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CT2700 AN ELECTRONIC ROUND ™ PROGRAMMABLE THERMOSTAT CO N O N A F AUTO Three Thermostat Wires If you have three wires for heating only and can operate the fan using the FAN ON switch, this thermostat works with your system. However, some hot water (zoned) heating systems have three thermostat wires. The thermostat will work only if you install an isolating relay on these systems. For details, call Honeywell Customer Assistance Center at 1-800-468-1502. 3 MOUNT WALLPLATE IMPORTANT Level for appearance only. The thermostat functions normally even when not mounted level. Position the decorator cover plate and wallplate on the wall. Level the wallplate for appearance if desired. Use a pencil to mark the two mounting holes that best fit the application. See Fig. 3. WALL DECORATOR COVER PLATE PLASTIC SCREW ANCHOR (2) WALLPLATE OFF HEAT OL 4 WIRE WALLPLATE TERMINALS The CT2700 Thermostat is powered through the heating/ cooling system and is adaptable to most 4-wire, 18 to 30 Vac heating-cooling systems. Refer to Figs. 4 through 6 for some typical system wiring diagrams. T8700 R G Y W 1 L1 (HOT) L2 HEATING PRIMARY CONTROL 24V COOLING CONTACTOR FAN RELAY 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. M12525 Fig. 4. CT2700 wiring diagram, 4-wire heat/cool system. T8700 R G Y W HEATING 1 RELAY AND FAN COIL 24V 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. M12543 Fig. 5. CT2700 wiring diagram, 2-wire, heat-only system. M12532 Fig. 3. Mounting decorator cover plate and wallplate to wall. Remove the decorator cover plate and wallplate from the wall, and drill two 3/16-inch holes in the wall (if drywall). For firmer wall material such as plaster or wood, drill 7/32-inch holes. Gently tap provided anchors into the drilled holes until flush with the wall. Reposition the decorator cover plate and wallplate, pulling wires through the wiring opening. Loosely insert the mounting screws into the holes. Level for appearance only; the thermostat functions properly even when not level. Tighten the mounting screws. T8700 R G Y W FAN COIL 1 L1 (HOT) L2 COOLING CONTACTOR COIL 24V 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. M12544 Fig. 6. CT2700 wiring diagram, 3-wire, cool-only system. IMPORTANT Use 18-gauge maximum wire to wire the thermostat. 3 69-1085