Carrier 11-808-427-01 Air Conditioner User Manual


 
RTU Open 7
Screw the RTU Open into an enclosed panel using the mounting slots on the cover plate. Leave about 2 in. (5
cm) on each side of the controller for wiring.
To wire the controller for power
The RTU Open is powered by a Class 2 power source. Take appropriate isolation measures when
mounting it in a control panel where non-Class 2 circuits are present.
CAUTIONS
Do not power pilot relays from the same transformer that powers the RTU Open.
In most cases, the RTU Open will be powered from the control power transformer provided with the
rooftop equipment. If you must use a separate control power transformer, additional precautions
must be taken to ensure that the auxiliary transformer is in-phase with the rooftop equipment’s
control power transformer. See Using an auxiliary control power transformer (page 8).
Using the rooftop equipment control power transformer
1 Remove power from the 24 Vac transformer.
2 Remove connector assembly from RTU Open's J1 connector.