Electrical Phasing (Three Phase Motors); Compressor Crankcase Heaters; Rrucm And Reliatel Controls - Trane RRU150F N Series Installation, Operation And Maintenance Manual

motor winding temperatures that will decrease motor life.
If the voltage imbalance is over 2 percent, notify the
proper agencies to correct the voltage problem before
operating this equipment.
Electrical Phasing (Three Phase
Motors)
The compressor motor(s) and the supply fan motor are
internally connected for the proper rotation when the
incoming power supply is phased as A, B, C.
Proper electrical supply phasing can be quickly
determined and corrected before starting the unit by using
an instrument such as an Associated Research Model 45
Phase Sequence Indicator and following the steps below:
WARNING
Hazardous Voltage w/Capacitors!
Failure to disconnect power and discharge capacitors
before servicing could result in death or serious injury.
Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout/
tagout procedures to ensure the power cannot be
inadvertently energized. Verify with an appropriate
voltmeter that all capacitors have discharged.

Turn the field supplied disconnect switch that
provides power to the main power terminal block or
to the "Line" side of the optional factory mounted
disconnect switch to the "Off" position.

Connect the phase sequence indicator leads to the
terminal block or to the "Line" side of the optional
factory mounted disconnect switch as follows:
Black (phase A) to L1
Red (phase B) to L2
Yellow (phase C) to L3

Close the field supplied main power disconnect
switch or circuit protector switch that provides the
supply power to the unit.
WARNING
Live Electrical Components!
Failure to follow all electrical safety precautions when
exposed to live electrical components could result in
death or serious injury.
When it is necessary to work with live electrical
components, have a qualified licensed electrician or
other individual who has been properly trained in
handling live electrical components perform these
tasks.
RRU-SVX02F-EN

Observe the ABC and CBA phase indicator lights on
the face of the sequencer. The ABC indicator light will
glow if the phase is ABC. If the CBA indicator light
glows, open the disconnect switch or circuit
protection switch and reverse any two power wires.

Restore the main electrical power and recheck the
phasing. If the phasing is correct, open the disconnect
switch or circuit protection switch and remove the
phase sequence indicator.

Compressor Crankcase Heaters

Each compressor can be equipped with a crankcase
heater. The proper operation of the crankcase heater is
important to maintain an elevated compressor oil
temperature during the "Off" cycle to reduce oil foaming
during compressor starts. Oil foaming occurs when
refrigerant condenses in the compressor and mixes with
the oil. In lower ambient conditions, refrigerant migration
to the compressor could increase.
When the compressor starts, the sudden reduction in
crankcase pressure causes the liquid refrigerant to boil
rapidly causing the oil to foam. This condition could
damage compressor bearings due to reduced lubrication
and could cause compressor mechanical failures.
Before starting the unit in the "Cooling or
Dehumidification" mode, remove the jumper on terminals
5 and 6 (Energy Stop) and turn the main power disconnect
to the "On" position and allow the crankcase heaters to
operate a minimum of 8 hours.
Before closing the main power disconnect switch, insure
that the "Control Input" input is in the "Unoccupied" or
connection on RRUTS 7 an 8 is "Open."
Close the main power disconnect switch and the unit
mounted disconnect switch, if applicable.
To prevent injury or death from electrocution, it is the
responsibility of the technician to recognize this hazard
and use extreme care when performing service
procedures with the electrical power energized.

RRUCM and ReliaTel Controls

Upon power initialization, the controls perform self-
diagnostic checks to insure that all internal controls are
functional. The Status LED located on the RRUCM and the
Liteport LED located on the RTRM module is turned "On"
within one second of power-up if internal operation is
okay.
Installation
29