29
CHART 4 -- INDOOR UNIT COMMUNICATION ERROR SIZE 9K AND 12K
Reset main power and
restart system using remote.
Problem persists?
.
No further action is
required
No
Yes
Measure Volts DC on
outdoor TB between 1 & 3.
Ok?**
Yes
Check the wires and
connections between
Indoor and outdoor units*
No
Fix connection or
replace wiring
No
Yes
Replace outdoor board.
** There is a 2 to 3 minute window to take the measurement before the diagnostic light is on again.
Measure Volts DC on
indoor TB between 1 & 3.
Ok?**
No
Replace indoor board.
Recheck wiring and
connections
Notes:
Before measuring the Volts DC on outdoor TB,
disconnect the field wire on terminal 1.
Before measuring the Volts DC on Indoor TB,
disconnect the field wire on terminal 1.
Have the red probe of the meter on terminal 1
and the black probe on terminal 3. Reconnect
wiring when measurements are complete.
Reset main power and
restart system using remote.
Problem persists?
.
No further action is
required
No
Yes
Measure Volts DC on
outdoor TB between 1 & 3.
Ok?**
Yes
Check the wires and
connections between
Indoor and outdoor units*
No
Fix connection or
replace wiring
No
Yes
Replace outdoor board.
* Make sure wires are connected per connection diagrams. Failing to do that will result in a communication error.
** There is a 2 to 3 minute window to take the measurement before the diagnostic light is on again.
Measure Volts DC on
indoor TB between 1 & 3.
Ok?**
No
Replace indoor board.
Recheck wiring and
connections
Notes:
Before measuring the Volts DC on outdoor TB,
disconnect the field wire on terminal 1.
Before measuring the Volts DC on Indoor TB,
A08181
38/40MVC, MVQ