All UniTrane ^® fan-coils are available with electric heating coils. Low vertical units have electric heat available only on units with a two-row cooling coil.

Coil Construction and Location

Electric heat coils are open wire type with a nickel chrominum element design. All coils are located in the preheat position on the standard UniTrane fan-coil design and in the reheat position on the low vertical fan- coil units.

Power Supply

Units have single-point power since the electric heating elements operate on line voltage. In addition, all control options are 24-volt, utilizing a factory- installed transformer.

Control Type

Fan-coil units with electric heat are controlled by either of the standard control options: the thermostat module or terminal unit controller (TUC). Both controllers use PWM (pulse-width modulation) outputs that calculate the electric heat output based on the capacity request and the electric heat cycles per hour. For example, if the electric heat cycles per hour is configured for six cycles (as Trane recommends) the controller bases the output on or off time on six 10-minute periods. If the capacity request is 40%, the controller controls the electric heat output on for approximately four minutes each period.

Electric Heat Features

• All fan-coil units are UL approved.
• Units require only a single-point electrical connection.
• All electric heating coils are interlocked with the fan motor switch. Therefore, electric heat operation is only possible when the fan is running.
• Each unit has a transformer, eliminating the need for field installation of a step-down transformer.
• A unit mounted magnetic contactor(s) is (are) supplied on all unit voltages. • A high temperature cutout with automatic reset de-energizes the electric heat in the event of an overheat condition.
• When hydronic heating is active, a high temperature switch will disable the electric heat.