SERVICING
39
NOTE
: Upon start up in communicating mode the circuit
board may display an “Ec” error. This is an indication that
the dip switches on the control board need to be configured
in accordance with the Electric Heating Airflow Table. Con
-
figuring the dip switches and resetting power to the unit will
clear the error code.
Within the thermostat user menu, CTK04 communicating
thermostat will display 20 kW for OFF-OFF-ON dip switch
selection.
Troubleshooting
Electrostatic Discharge (ESD) Precautions
NOTE
: Discharge body's static electricity before touching
unit. An electrostatic can adversely affect electrical compo
-
nents.
Use the following precautions during air handler installation
and servicing to protect the integrated control module from
damage. By putting the air handler, the control, and the per-
son at the same electrostatic potential, these steps will help
avoid exposing the integrated control module to electrostatic
discharge. This procedure is applicable to both installed and
uninstalled (ungrounded) blowers.
1. Disconnect all power to the blower. Do not touch the
integrated control module or any wire connected to the
control prior to discharging your body’s electrostatic
charge to ground.
2. Firmly touch a clean, unpainted, metal surface of the air
handler blower near the control. Any tools held in a per-
son’s hand during grounding will be discharged.
3. Service integrated control module or connecting wiring
following the discharge process in step 2. Use caution
not to recharge your body with static electricity; (i.e., do
not move or shuffle your feet, do not touch ungrounded
objects, etc.). If you come in contact with an ungrounded
object, repeat step 2 before touching control or wires.
4. Discharge your body to ground before removing a new
control from its container. Follow steps 1 through 3 if
installing the control on a blower. Return any old or new
controls to their containers before touching any un-
grounded object.
INDOOR UNIT TROUBLESHOOTING FOR TXV APPLICABLE UNIT (MBVC**00AA-1)
Diagnostic Chart
WARNING
HIGH VOLTAGE
DISCONNECT ALL POWER BEFORE SERVICING OR
INSTALLING THIS UNIT. MULTIPLE POWER SOURC-
ES MAY BE PRESENT. FAILURE TO DO SO MAY
CAUSE PROPERTY DAMAGE, PERSONAL INJURY
OR DEATH.
Refer to the Troubleshooting Chart at the end of this manual
for assistance in determining the source of unit operation-
al problems. The 7 segment LED display will provide any
active fault codes. An arrow printed next to the display indi-
cates proper orientation (arrow points to top of display). See
following image.
7 Segment
Diagnos
�
c
Display
Fault Recall
The integrated control module is equipped with a momen-
tary push-button switch that can be used to display the last
six faults on the 7 segment LED display. The control must be
in Standby Mode (no thermostat inputs) to use the feature.
Depress the push-button for approximately two seconds.
The LED display will then display the six most recent faults
beginning with the most recent fault and decrementing to the
least recent fault. The faults may be cleared by depressing
the button for greater than five seconds.
NOTE
: Consecutively repeated faults are displayed a max-
imum of three times. Example: A clogged return air filter
causes the air handler’s motor to repeatedly enter a limiting
condition. The control will only store this fault the first three
consecutive times the fault occurs.
