Trane Tracer ZN517, Инструкция по установке и эксплуатации

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Chapter 4 Sequence of operations for the 2-heat/2-cool configuration
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Discharge air tempering
Discharge air tempering (also called supply air tempering) prevents occu-
pant discomfort caused by cold outside air being brought into a space
through the outside air damper. This is an important feature in cold cli-
mates because the outside air damper is never fully closed for ventilation
purposes. Discharge air tempering starts when:
•
The controller is in heating mode.
•
The space is otherwise satisfied (no heating or cooling required).
•
Ventilation air is passing through the unit
•
The discharge air temperature falls 10°F (5.6°C) below the occupied
heating setpoint.
Tempering stops when the occupied heating setpoint is exceeded. To
enable this function, use the Rover service tool to select Supply Air Tem-
pering Enabled.
Demand control ventilation
The Tracer ZN517 unitary controller modulates the outside air damper
position in direct response to the CO
2
level, regulating the amount of out-
door air allowed to enter. This function is referred to as demand control
ventilation. Demand control ventilation requires that the two triac (3-
wire floating point) outputs be used to control the damper actuator. The
minimum damper position will increase as CO
2
levels rise above
500 ppm. The function executes with a 3-minute loop frequency to allow
time for the sensor to respond.
To enable this function, use the Rover service tool to configure the Tracer
ZN517 as follows:
•
Configure AI1 as a carbon dioxide sensor
•
Enter a minimum CO
2
level (Control Point)
(factory default: 500 ppm).
•
Enter a maximum CO
2
threshold (Threshold)
(factory default: 1500 ppm).
When the CO
2
level reaches the threshold, the minimum position is
100% open.
Unit protection strategies
The following strategies are initiated when specific conditions exist in
order to protect the unit or building from damage:
•
Filter maintenance timer
•
Fan off delay
•
Fan status