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TTA-SVX02C-EN
Safety Controls
Note:
All of these controls may not be installed on your unit, check
electrical schematic.
Low Outdoor Ambient Cooling
The Evaporator Defrost Control is standard equipment on
Air Handlers and will permit low ambient cooling down to 35
degrees F. For cooling operation down to 0 degrees F, use an
Accessory Head Pressure Control on the outdoor unit.
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
indoor coil temperature drops below its 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. This control will stop the compressor and the
outdoor fans if suction pressure drops below the Low Pressure
Cut-Out setting. Once the suction pressure has returned to
normal, the compressor and outdoor 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’s
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 windings exceeds its design trip temperature.
Note:
The IOL will put the compressor back in operation
once the compressor motor heat has dropped below the
trip setting; however, a check of the refrigerant and
electrical systems 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?
