– 39 –
•
3°F to 5°F above refrigerator set point - medium
speed.
• 5.5°F to 7°F above refrigerator set point - high
speed.
Note:
The compressor will run at medium speed if
the freezer temperature is 20°F or more above the
setpoint.
The use of 3-phase power eliminates the need for
the relay, capacitor, and individual start and run
windings; therefore, the start, run, and common
pins found on conventional compressors are not
applicable on this 3-phase model. Compressor pin
functions are identical and compressor lead wire
confi guration is of no importance. A resistance of
9
Ω
to 11
Ω
should be read between any 2 of the
3 pins. Should an open occur in the compressor
winding or should one of the compressor lead wires
become open or disconnected, the inverter will stop
voltage output to the compressor.
High compressor torque enables the compressor
to start against high pressure in the sealed system.
When power has been disconnected from an
operating unit, the high torque will enable the
compressor to start immediately upon power
restoration.
Compressor operation is extremely smooth and
cool. The compressor exterior may be slightly higher
than room temperature while operating; therefore, it
may be diffi cult to detect a running unit.
To verify that the compressor is running:
Disconnect power from the unit and place a hand
on the compressor. Reconnect power and feel for
a vibration when the compressor tries to start. It
may take up to 8 seconds before the compressor
attempts to start.
Note:
When ordering a replacement compressor,
order both the compressor and inverter. Replace
the compressor fi rst. If, after compressor
installation, the compressor fails to start,
replace the inverter.
When servicing the compressor, it is important
to dress the wiring to keep low voltage DC wiring
and 120 VAC wiring separate.
•
•
Single-Speed Compressor
The compressor is a reciprocating type. Refer to
the mini-manual for the BTU/hour rating and the
compressor capacity test specifi cation.
To verify that the compressor is running:
WARNING
: During normal operation, the
temperature of the single-speed compressor may
be hot. Use caution to avoid injury and wear Kevlar
®
gloves or equivalent protection.
Disconnect power from the unit. Wait 3 to 5 minutes
for pressure to equalize. Place a hand on the
chassis, near the compressor. Reconnect power and
feel for a vibration when the compressor tries to
start.
Note:
The single-speed compressor will start right
away if pressure is equal.
A ¼-in. O.D. copper process tube is provided for
access to the low-pressure side of the refrigeration
system.
Refer to the compressor replacement instructions
included with the replacement compressor.
Evacuate and recharge the system using currently
accepted procedures. (See
Evacuation and Charging
Procedure
.)
