Troubleshooting - Carrier 40MAQ Series Service Manual

Follow me
1 If the indoor PCB receives the signal which results from
pressing the FOLLOW ME button on remote controller, the
buzzer will emit a sound and this indicates the follow me
function is initiated. But when the indoor PCB receives
signal which sent from remote controller every 3 minutes,
the buzzer will not respond. When the unit is running with
follow me function, the PCB will control the unit according
to the temperature from follow me signal, and the
temperature collection function of room temperature sensor
will be shielded, but the error detective function of room
temperature sensor will be still valid.
2 When the follow me function is available, the PCB will
control the unit according to the room temperature from the
remote controller and the setting temperature.
3 The PCB will take action to the mode change information
from remote controller signal, but it will not affected by the
setting temperature.
4 When the unit is running with follow me function, if the
PCB does not receive any signal from remote controller for
7 minutes or pressing FOLLOW ME button again, the
follow me function will be turned off automatically, and the
temperature will control the unit according to the room
temperature detected from its own room temperature sensor
and setting temperature.
Self Clean
For heat pump models which are provided with this function, after
running in cooling or drying mode, if the user press "Self Clean"
button on remote controller, indoor unit runs in fan only mode for
13 minutes, then low heat operation and finally in fan only again.
This function can keep the inside of indoor unit dry and prevent
breeding of mold.
Refrigerant Leakage Detection
With this new technology, the display area will show "EC" when
the outdoor unit detects refrigerant leakage. This feature is only
available in the cooling mode for 1 to 1 systems.
T2: indoor coil temp. Tcool: sample temp. of T2 when the
compressor starts. During the first 5 minutes after compressor's
start, if the situation that T2 < Tcool- 3.6_ F does not last for 4
seconds continuously, the system will record suspected refrigerant
leakage once, and the compressor will stop.
If the above case happened three times continuously, the system
will judge refrigerant leakage. Indoor unit will indicate error code
"EC" and the unit will turn off automatically.
Refrigerant leakage count will reset under following situation:
During the first 5 minutes after compressor's start, the situation that
T2 < Tcool- 3.6_ F lasts for 4 seconds continuously.
Evaporator anti- freeze protection in cooling mode.
Non- cooling mode.
Louver Position Memory Function
When starting the unit again after shutting down, its louver will
restore to the angle originally set by the user, but the precondition
is that the angle must be within the allowable range, if it exceeds, it
will memorize the maximum angle of the louver. During operation,
if the power fails the louver will restore to the default angle.
46_F (8_C) Heating (heating setback)
In heating operation, the preset temperature of the air conditioner
can be as low as 46_F, which keeps the room temperature steady at
46_F and prevents household pipes from freezing when the house
is unoccupied for a long time in severe cold weather.
Silence operation
Press the "silence" button on remote controller to initiate
SILENCE function. When the Silence function is activated, the
compressor running frequency will keep lower than F2 and the
indoor unit will supply faint breeze, which will reduce the noise to
the lowest level and create a quiet and comfortable room for you.

TROUBLESHOOTING

This section provides the required flow charts to troubleshoot
problems that may arise.
NOTE: Information required in the diagnoses can be found
either on the wiring diagrams or in the appendix.
Required Tools:
The following tools are needed when diagnosing the units:
S Digital multimeter
S Screw drivers (Phillips and straight head)
S Needle- nose pliers
S Refigeration gauges
Recommended Steps
1 Refer to the diagnostic hierarchy charts below and
determine the problem at hand.
2 Go to the chart listed in the diagnostic hierarchy and follow
the steps in the chart for the selected problem.
For the ease of service, the systems are equipped with diagnostic
code display LED's on both the indoor and outdoor units. The
outdoor diagnostic display is on the outdoor unit board and is
limited to very few errors. The indoor diagnostic display is a
combination of flashing LED's on the display panel on the front of
the unit. If possible always check the diagnostic codes displayed on
the indoor unit first.
The diagnostic codes for the indoor and outdoor units are listed in
the appendix.
Problems may occur that are not covered by a diagnostic code, but
are covered by the diagnostic flow charts. These problems will be
typical air conditioning mechanical or electrical issues that can be
corrected using standard air conditioning repair techniques.
For problems requiring measurements at the control boards, note
the following:
1 Always disconnect the main power.
2 When possible check the outdoor board first.
3 Start by removing the outdoor unit top cover.
4 Reconnect the main power
5 Probe the outdoor board inputs and outputs with a digital
multi- meter referring to the wiring diagrams.
6 Connect the red probe to hot signal and the black probe to
the ground or negative.
7 Note that some of the DC voltage signals are pulsating
voltages for signal. this pulse should be rapidly moving at
all times when there is a signal present.
8 If it is necessary to check the indoor unit board you must
start by disconnecting the main power.
9 Next remove the front cover of the unit and then control
box cover.
10 Carefully remove the indoor board from the control box,
place it face up on a plastic surface (not metal).
11 Reconnect the main power and repeat steps 5,6, and 7.
12 Disconnect main power before reinstalling board to avoid
shock hazard and board damage.
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