Trane RAUC-C20, Installation Operation & Maintenance

Page: 65 / 112

SS-SVX09A-EN 65
Installation
Discharge Air Sensor (Honeywell 6RT1)
A discharge air sensor ships with each unit when the constant volume control option is ordered.
The sensor should be installed in a turbulent free area of the discharge air duct at a location that
will provide accurate supply air sensing. Refer to the illustration in
Figure 33 for installation and
sensor dimensional information.
WARNING
Hazardous Voltage!
Disconnect all electric power, including remote disconnects before servicing. Follow proper
lockout/tagout procedures to ensure the power can not be inadvertently energized. Failure to
disconnect power before servicing could result in death or serious injury.
Wire the sensor in accordance with the field connection diagram in Figure 32 . As shipped form the
factory, a resistor (7R1) is installed on terminal board 1TB8 terminals 5 & 6). Remove this resistor
when the sensor is installed. Shielded cable (Belden 8760 or equivalent) must be used when wiring
the sensor to the terminal board inside the unit’s control panel.
When the sensor is installed, it serves two functions;
1. It sends the supply air temperature to the master energy controller (MEC), in the form of an
analog input, to assist in the rate at which the system changes the space temperature. By
offsetting the actual zone thermostat setpoint, up or down, the MEC can closer control the zone
comfort level.
2. It serves as a low limit for the system when the supply air temperature reaches too high a delta
tee between the actual supply air temperature and the zone temperature to help prevent
overshooting of the zone thermostat setpoint.
Table 11. (Q667) Switching Subbase
Subbase Switch Positions
Check Continuity between These
Terminal Pairs
Circuit should
be Fan System
ON N/A 9 (Subbase) & 10 (Subbase) Closed
AUTO OFF
9 (Subbase) & 10 (Subbase) Open
5 (Subbase) & 5 (T’stat) Open
4 (Subbase) & 4(T’Stat) Open
AUTO HEAT
9 (Subbase) & 10 (Subbase) Open
5 (Subbase) & 5 (T’stat) Closed
4 (Subbase) & 4(T’Stat) Open
AUTO AUTO
9 (Subbase) & 10 (Subbase) Closed
5 (Subbase) & 5 (T’stat) Closed
4 (Subbase) & 4(T’Stat) Closed
AUTO COOL
9 (Subbase) & 10 (Subbase) Closed
5 (Subbase) & 5 (T’stat) Open
4 (Subbase) & 4(T’Stat) Closed