Device Setup; Device Programming; Default Values - Honeywell T775A User Manual

When wiring the input power, only one source of power
can be applied to the T775 (for example, 24 Vac or 120 Vac
or 240 Vac). Knockouts B and C can be used to gain access
to 120 Vac or 240 Vac input terminals and the load relay
output terminals.
See Fig. 11 through 14 for typical T775 wiring and
applications.
IMPORTANT: Erratic temperature readings from the
193987GA Sensor can be caused by poor wiring prac-
tices that must be avoided to assure proper operation:
• Do not route the temperature sensor wiring with
building power wiring.
• Do not locate the temperature sensor wiring next to
control contactors.
• Do not locate the temperature sensor wiring near
electrical motors.
• Do not locate the temperature sensor wiring near
welding equipment.
• Make sure good mechanical connections are made to
both the sensor and the controller.
• Do not mount the sensor with the leadwire end (wire
end) pointing up in an area where condensation can
occur.
If any of the above conditions cannot be avoided, use
shielded cable.
NOTE: Ground the cable shield at the T775 connection only,
not at the sensor connection ( see Fig. 5).

DEVICE SETUP

1. Determine the loads to be controlled and the operating
mode (heat or cool) and enter in the Device Programming
Worksheet.
For example: Load 1: Compressor 1 (cool)
Setpt 1 ______ On at _______
Diff 1 _______ Off at _______
2. For two sensor models (T775B), determine which
loads will be controlled from sensor A or sensor B and enter
on the worksheet.
For example: Load 1: Compressor 1 (cool)—Sensor A
Setpt 1 ______ On at _______
Diff 1 _______ Off at _______
3. Determine the setpoint (Setpt) and the switching dif-
ferential (Diff) for each load and enter on the worksheet.
For example: Load 1: Compressor 1 (cool)—Sensor A
Setpt 1 ______ 78°F On at _______
Diff 1 _______ 4°F Off at _______
4. Refer to the Control Algorithm subsection in Descrip-
tion/Operation section to calculate the load on and off tem-
peratures. Enter them on the worksheet. Remember that the
on/off outputs are off at setpoint in both the heating and
cooling operating modes. When in cooling mode, the load
will be turned off at setpoint plus the differential. When in
heating mode, the load will be turned on at setpoint minus the
differential.
For example: Load 1: Compressor 1 (cool)—Sensor A
Setpt 1 ______ 78°F
Diff 1 _______ 4°F
CAUTION
The T775 will not allow the user to program for
both heating and cooling loads to be energized at
the same time.
If this situation results, cooling loads will be
energized and heating loads will be prevented from
also energizing. The number (1,2,3,4) of these
nonenergized loads will flash along with the word
HEAT to indicate a call for both heating and cool-
ing loads controlled by one sensor has occurred and
to alert the user to reprogram the affected control
values.
5. Remove the T775 cover and enter the values listed on
the worksheet and the date in the first column on the label
inside the T775 cover.
Device Programming Worksheet
Load 1:
SetPt 1 ______________
Diff 1 _______________
Load 2:
Setpt 2 ______________
Diff 2 _______________
Load 3:
Setpt 3 ______________
Diff 3 _______________
Load 4:
Setpt 4 ______________
Diff 4 _______________

DEVICE PROGRAMMING

Default Values

When power is initially applied to the T775, the control
points will be at their default value set at the factory. Default
values are:
Setpoint
(°F)
Stage 1 72
Stage 2 70
Stage 3 68
Stage 4 66
7
T775A,B,C,D
INSTALLATION
On at _______ 82°F
Off at _______ 78°F
On at _______________
Off at _______________
On at _______________
Off at _______________
On at _______________
Off at _______________
On at _______________
Off at _______________
Differential Operating
(°F) Mode
2 Heat
2 Heat
2 Heat
2 Heat
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