16
TWA-SVX01A-EN
Safety Controls
Note:
All of these controls may not be installed on your unit,
check electrical schematic.
Evaporator Defrost Control (EDC)
This control is located in the Air Handler of Split Units. The
control’s sensing tube is imbedded vertically in the evaporator
coil, near the center. This device will stop the compressor if the
coil temperature drops below it’s setting. The indoor air will still
circulate across the coil, bringing the temperature of the coil
back up to the cut-in temperature of the evaporator defrost
control.
Low Pressure Cut-Out (LPCO)
This control’s sensor is located in the suction (gas) line, near
the compressor. The control will stop the compressor and
outdoor fans if suction pressure drops below the Low Pressure
Cut-Out setting. Once the suction pressure has returned to
normal, the compressor and out door fans will cycle back on.
High Pressure Cut-Out (HPCO)
This control’s sensor is located in the discharge line. This
device will shut off the compressor and the outdoor fan(s) if
the discharge pressure exceeds the High Pressure Cut-Out
setting. Once the discharge pressure has returned to normal,
the compressor will cycle back on.
Internal Overload Protector (IOL)
This device is a current/thermal actuated warp switch,
imbedded in the compressor motor windings. It will shut off the
compressor if the temperature or current of the compressor
motor windings exceeds it’s design trip temperature.
Note: The IOL will put the compressor back in opera-
tion once the compressor motor heat has dropped
below the trip setting; however, a check of the
refrigerant and electrical system should be made to
determine the cause and be corrected.
System Pre-Start Procedure
Installation Checklist
Complete this checklist once the unit is installed to verify
that all recommended procedures have been accomplished
before starting the system. Do not operate the system until all
items covered by this checklist are complete.
[ ] Inspect unit location for proper required service clear-
ances.
[ ] Inspect unit location for proper free air clearances.
[ ] Inspect unit location for secure, level mounting position.
Refrigerant Piping
[ ] Performed initial leak test?
[ ] Connected properly sized and constructed liquid and suc-
tion lines to the connection stubs at both the indoor and
outdoor units?
[ ] Insulated the entire suction line?
[ ] Insulated portions of liquid line exposed to extremes in
temperature?
[ ] Evacuated each refrigerant circuit to 350 microns?
[ ] Charged each circuit with proper amount of R-22?
Electrical Wiring
[ ] Provided unit power wiring (with disconnect) to proper ter-
minals in the unit control section?
[ ] Installed system indoor thermostat?
[ ] Installed system low voltage interconnecting wiring to
proper terminals of outdoor unit, indoor unit and system
thermostat?
