Trane MCD/MWD-512 Installation & Operation Manual page 26

Table 15 - Trouble-shooting (electric heating only)
No heating. A. Incorrect control switch setting.
B. Defective control switch.
C. Defective heater temp. limit switch.
D. Unit wiring is incorrect.
E. The heater temperature limit switch
has opened.
F . Dirty air filter.
G. Indoor unit coil fins obstructed.
H. Defective electrical component.
26
Trouble-shooting
(electric heating only)
1. Check the thermostat's set points and
operation.
1. Check operation and the signal to the
heating device.
1. Check the heater temp. limit switch.
1. Check the wiring.
1. Check tightness of the indoor unit's
fan on its shaft.
1. Check the filter.
1. Check the filter is not missing.
1. Check all the components are correct.
2. Check the fin block.
Controller troubleshooting
The controller has a built-in self-
diagnostic function. The following
LEDs are used to indicate the
problem or status.
Auto/High/Medium/Low LEDs
show fan speed setting.
Cool LED shows the COOL operating
mode.
- If the cooling fail protection is
active, this LED will be blinking
with the signal as per Figure 14, A.
- If anti-overheat or low ambient
protection is active, this LED will
be blinking with the signal as per
Figure 14, B.
Heat LED shows the HEAT
operating mode.
- If the heating fail protection is
active, this LED will be blinking
with the signal as per Figure 14, A.
- If the compressor overload
protection is active, this LED will
be blinking with the signal as per
Figure 14, B.
7-segment LED (2 digits) shows the
room temperature if lit, and the
setting temperature while blinking.
1. Change the settings.
1. Repair or replace.
1. Replace the defective switch.
1. Modify the wiring as indicated on
the wiring diagram.
1. Tighten the fixing screws.
1. Clean the filter.
1. Fix the filter.
1. Replace the defective component.
2. Clean the fins.
Dot LED after the first digit of
7-segment LED, if blinking indicates
any of the room, freeze or defrost
sensor is open or short circuit.
Dot LED after the second digit of
7-segment LED, indicates that the
compressor is on if lit, and indicates
either the freeze or defrost
protection is active if blinking.
Figure 14 - LEDs blinking signals
On-board setting
There is 1 jumper location on the
main control board which is related
to this setting. If the jumper is put at
OP4 location, both heat pump and
heater can be operated. If not, only
heat pump can be operated.
SS-SVX07B-E4