Compressor Crankcase Heaters; Test Modes - Trane Precedent WSC060ED Installation, Operation And Maintenance Manual

Pre-Start
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:
• 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!
During installation, testing, servicing and
troubleshooting of this product, it may be 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. Failure to follow all electrical
safety precautions when exposed to live electrical
components could result in death or serious injury.
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.
• 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 is 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
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damage compressor bearings due to reduced lubrication
and could cause compressor mechanical failures.
Before starting the unit in the "Cooling" mode, set the
system switch to the "Off" position and turn the main
power disconnect to the "On" position and allow the
crankcase heater to operate a minimum of 8 hours.
Before closing the main power disconnect switch, insure
that the "System" selection switch is in the "Off" position
and the "Fan" selection switch is in the "Auto" position.
Close the main power disconnect switch and the unit
mounted disconnect switch, if applicable.
WARNING
Live Electrical Components!
During installation, testing, servicing and
troubleshooting of this product, it may be 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. Failure to follow all electrical
safety precautions when exposed to live electrical
components could result in death or serious injury.
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.
Upon power initialization, the RTRM performs self-
diagnostic checks to insure that all internal controls are
functional. It also checks the configuration parameters
against the components connected to the system. The
Liteport LED located on the RTRM module is turned "On"
within one second of power-up if internal operation is
okay.
Use one of the following "Test" procedure to bypass some
time delays and to start the unit at the control panel. Each
step of unit operation can be activated individually by
temporarily shorting across the "Test" terminals for two to
three seconds. The Liteport LED located on the RTRM
module will blink when the test mode has been initiated.
The unit can be left in any "Test" step for up to one hour
before it will automatically terminate, or it can be
terminated by opening the main power disconnect switch.
Once the test mode has been terminated, the Liteport LED
will glow continuously and the unit will revert to the
"System" control.

Test Modes

There are three methods in which the "Test" mode can be
cycled at LTB-Test 1 and LTB-Test 2.
1. Step Test Mode - This method initiates the different
components of the unit, one at a time, by temporarily
shorting across the two test terminals for two to three
seconds.
RT-SVX39B-EN