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Programmable Functions, Ranges, and Factory Defaults
15: Low-Pressure Switch Test
WARNING: EXPLOSION HAZARD .
During this test, low- and high-pressure faults are
ignored. The system must be monitored closely
during this test and must be shut down immediately
if pressures exceed 625 PSI (44 Bar). Failure to obey
this warning could result in death or serious injury.
NOTICE: The system should only be operated for a
brief period of time if pressures fall below 30 PSI (2 Bar).
If the system is operated below 30 PSI (2 Bar) for an
extended period of time, the system can ingest liquid
and compressor damage can occur.
The low-pressure switch test is used to test the low-
pressure circuit for a fault or to test for a low charge
in the system. This test can also be used to charge a
system. Press the Mode button to enter the low-pressure
switch test. During this test, the unit will operate in cool
mode at high fan speed, and the display will show "OA"
(closed circuit) if the low-pressure switch circuit is OK or
"FA" (open circuit) if the low-pressure switch has a fault
or the system is low in charge. Press the Fan button to
exit this test mode.
16: High-Pressure Switch Test
WARNING: EXPLOSION HAZARD .
During this test, low- and high-pressure faults are
ignored. The system must be monitored closely
during this test and must be shut down immediately
if pressures exceed 625 PSI (44 Bar). Failure to obey
this warning could result in death or serious injury.
NOTICE: The system should only be operated for a
brief period of time if pressures fall below 30 PSI (2 Bar).
If the system is operated below 30 PSI (2 Bar) for an
extended period of time, the system can ingest liquid
and compressor damage can occur.
The high-pressure switch test is used to test the high-
pressure circuit for a fault, an overcharged system, or
the loss of air flow. Press the Mode button to enter the
high-pressure switch test. During the test, the unit will
operate in cool mode at high fan speed, and the display
will show "OA" (closed circuit) if the high-pressure switch
circuit is OK or "FA" (open circuit) if the high-pressure
switch circuit has a fault or system is overcharged or has
loss of condenser air flow. Press the Fan button to exit
this test.
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17: LED Segment Test
Press the Mode button to test the display. All LED
segments should display. Press the Fan button to exit this
test.
18: Sleep Mode
Select "SL" for sleep mode and the LEDs remain dim or
the back light remains off until a key is pressed, which
will temporarily brighten the display. Select On and the
Q3 control LEDs stay at the current brightness setting.
19: Cool-Only Mode
Select "CL" for cool-only operation and the unit will
operate in cooling or (optional) aux heat/heat modes.
NOTICE: The unit must be placed in CL Mode . If
the unit is left in HP Mode, unit damage can occur .
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In "CL" cool-only mode, a five-minute compressor
delay will initiate whenever the compressor shuts
down on the set point, a fault occurs, or there is
a power outage. The five-minute delay will begin
immediately after the compressor shuts down.
The Q3 control will show the remaining time delay
countdown at two-second intervals when the
compressor is called to operate within the five-
minute countdown period. If the five-minute delay
period has passed before the compressor is called
to operate, the compressor will come on with no
delay.
20: High-Pressure Restart Delay
This function is used when the standard three-minute
delay during the high-pressure fault routine requires
an extended restart delay. The restart delay can be
increased up to five minutes between high-pressure fault
off cycle.
21: Anti-Icing Routine Adjustment
The anti-icing routine prevents ice build up on the
evaporator coil during extended periods of cooling
operation. Installation variables such as grille sizes,
length of ducting, insulation, and ambient temperatures
determine the run time required to achieve the set
point. Factors that substantially increase run time include
operating the system with hatches and doors open, and
programming an unrealistic set point [for example 65 °F
(18 °C)]. Such situations can cause the evaporator to
form ice on warm, humid days.
Universal Air Conditioning Unit
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Troubleshooting
