Trane LO - Manual (Page 72)

Tracer ® ZN.520
72 UNT-IOM-6
Dehumidification is possible when mechanical cooling is available,
the heating capacity is located in the reheat position, and the space
relative humidity setpoint is valid.The controller starts dehumidifying
the space when the space humidity exceeds the humidity setpoint.
The controller continues to dehumidify until the sensed humidity falls
below the setpoint minus the relative humidity offset.The controller
uses the cooling and reheat capacities simultaneously to dehumidify
the space. While dehumidifying, the discharge air temperature is
controlled to maintain the space temperature at the current setpoint.
A typical scenario involves high humidity and high temperature load of
the space.The controller sets the cooling capacity to 100% and uses
the reheat capacity to warm the discharge air to maintain space
temperature control.Dehumidification may be disabled via Tracer or
configuration.
Note: If the unit is in the unoccupied mode, the dehumidification
routine will not operate.
Because this controller utilizes LonWorks™ technology, the control-
ler can send or receive data (setpoint, heat/cool mode, fan request,
space temperature, etc.) to and from other controllers on the commu-
nication link, with or without the existence of a building automation
system. This applies to applications where multiple unit controllers
share a single space temperature sensor (for rooms with multiple
units but only one zone sensor) for both standalone (with communica-
tion wiring between units) and building automation system applica-
tions. For this application you will need to use the Rover service tool.
For more information on setup, refer to the Trane publication EMTX-
IOP-2.
The Tracer ® ZN.520 controller has four available binary inputs. Nor-
mally, these inputs are factory-configured for the following functions:
• Binary input 1: Low temperature detection (freezestat)
• Binary input 2: Condensate overflow
• Binary input 3: Occupancy/ Generic
• Binary input 4: Fan status
Note: The generic binary input can be used with a Tracer Summit ®
building automation system only.
Each binary input default configuration (including normally open/
closed) is set at the factory.However, you can configure each of the
four binary inputs as normally open or normally closed. The controller
will be set properly for each factory-supplied binary input end-device.
When no device is connected to the input, configure the controller’s
Dehumidification
Data Sharing
Binary Inputs