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System Operation
The outdoor unit and indoor blower cycle on demand from
the room thermostat. When the thermostat blower switch is
in the
ON
position, the indoor blower operates continuously.
Compressor Time Delay (TD1)
A compressor time delay is used to prevent compressor
short cycling and to prevent the compressor from running
backwards. When there is demand for a cooling cycle, the
control delays compressor operation for about 5 minutes (+
2 minutes). Do not bypass the control.
High Pressure Switch
HSXA12 units are equipped with a high pressure switch
that is located in the liquid line of the compressor. The
switch (SPST, manual reset, normally closed) removes
power from the compressor when discharge pressure rises
above factory setting at 640 + 10 psi.
Low Pressure Switch
HSXA12 units are also equipped with a low pressure switch
that is located in the vapor line of the compressor. The
switch (SPST, auto−reset, normally closed) removes power
from the compressor when vapor line pressure drops be-
low factory setting at 40 + 5 psi.
Filter Drier
A filter drier is shipped with each HSXA12 unit. The filter
drier must be field installed in the liquid line between the
liquid line service valve and the expansion valve.
This fil-
ter drier must be installed to ensure a clean, moisture−
free system. Failure to install the filter drier will void
the warranty.
A replacement filter drier is available as
from Lennox.
Maintenance
WARNING
Electric shock hazard. Can cause inju-
ry or death. Before attempting to per-
form any service or maintenance, turn
the electrical power to unit OFF at dis-
connect switch(es). Unit may have
multiple power supplies.
Maintenance and service must be performed by a qualified
installer or service agency. At the beginning of each cooling
season, the system should be checked as follows:
1 − Clean and inspect the outdoor coil. The coil may be
flushed with a water hose. Ensure the power is turned
off before you clean the coil.
2 − Outdoor fan motor is prelubricated and sealed. No fur-
ther lubrication is needed.
3 − Visually inspect connecting lines and coils for evidence
of oil leaks.
4 − Check wiring for loose connections.
5 − Check for correct voltage at unit (unit operating).
6 − Check amp−draw outdoor fan motor.
Unit nameplate _________ Actual ____________ .
NOTE − If owner complains of insufficient cooling, the
unit should be gauged and refrigerant charge
checked. Refer to section on refrigerant charging in
this instruction.
Indoor Coil
1 − Clean coil, if necessary.
2 − Check connecting lines and coils for evidence of oil
leaks.
3 − Check condensate line and clean, if necessary.
Indoor Unit
1 − Clean or change filters.
2 − Adjust blower speed for cooling. Measure the pressure
drop over the coil to determine the correct blower CFM.
Refer to the unit information service manual for pressure
drop tables and procedure.
3 −
Belt Drive Blowers −
Check belt for wear and proper
tension.
4 − Check all wiring for loose connections
5 − Check for correct voltage at unit (blower operating).
6 − Check amp−draw on blower motor
Unit nameplate_________ Actual ____________.
Optional Accessories
Refer to the Engineering Handbook for optional accesso-
ries that may apply to this unit. The following may or may
not apply:
Loss of Charge Kit
High Pressure Switch Kit
Compressor Monitor
Compressor Crankcase Heater
Hail Guards
Mounting Bases
Timed Off Control
Stand−off Kit
Sound Cover
Low Ambient Kit
