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T7770A,B,C,D,E,F,G, Wall Modules

GENERAL

The T7770A through G are a family of direct wired wall modules for use with Honeywell Excel 600, 500, 100, 80, 20, and W7750, W7751, W7752, W7753, W7761 Controllers. All models have a space temperature sensor; some models have setpoint adjustment, override with LED, and fan switch.

DESCRIPTION

The T7770A through G are a family of direct wired wall modules for use with Honeywell Excel 600, 500, 100, 80, 20, and W7750, W7751, W7752, W7753, W7761 Controllers. All models have a space temperature sensor; some models have setpoint adjustment, override with LED, and fan switch.

SPECIFICATIONS

Models:

Table 1. T7770 Wall Module Models.

 

NOTE: Refer to T7770A through G Installation Instructions, 95-7538, for wall module settings and wiring diagrams. Some T7770 features may not be available with all controllers.

 

Construction:

Two-piece construction, a cover and an internally wired subbase. Field wiring 14 to 22 AWG (2.0 to 0.34 mm²) connects to a terminal block in the subbase. The wall module is activated by plugging into the prewired subbase.

Temperature Sensor Operating Range:

45 to 99°F (10 to 37.2°C).

Temperature Sensor Accuracy

T7770A-G 20K Ohm Nonlinearized Sensor:

All T7770 models are furnished with a 20K Ohm nonlinear NTC temperature sensor that follows a specific temperature-resistance curve. See Fig. 1. Honeywell controllers used with the T7770 employ an algorithm that provides readings close to the actual temperature. Table 2 summarizes the T7770 nonlinearized sensor accuracy for normal operating temperatures. Across the range of 41 to 99°F (5 to 37°C) the accuracy is better than ± 0.75°F (±0.42°C).

 

Fig. 1. Temperature verses resistance for nonlinear sensor.

 

Table 2. Nonlinear Temperature Sensor Accuracy.

 

Communications:

Except for the T7770A1006, T7770A1014 models, T7770s all have an E-Bus communications port. If needed, the jack plug must be removed in the field, and terminals 1 and 2 wired according to the installation instructions. E-Bus communication is not applicable when the wall modules are used with Excel 600/500/100/80/20 Controllers. The E-Bus is insensitive to polarity, minimizing installation errors due to miswiring.

The recommended wire size for the E-Bus is Level IV, 22 AWG (0.34 mm²) plenum or non-plenum rated, nonshielded, twisted pair, solid conductor wire.

 

T7770B,C,E,F Setpoint Adjustment:

For Wall Modules with a setpoint adjustment, the controller must be programmed for the values in Table 3.

 

Table 3. Setpoint Values.

 

T7770C,D,E,F, and G Wall Module Bypass Override /LED Operation

When Used With Excel 10 Controllers:

The controller provides timed occupied and unoccupied temperature setpoints for the Wall Module, see Fig. 2. The bypass pushbutton is used to change the controller into the modes shown in Table 4 and Fig. 3. The override LED displays the override status of the controller.

Fig. 2. LED and bypass pushbutton locations.

 

 

Table 4. Wall Module Operation.