Troubleshooting When Multiple Indoor Units Are Connected To Cool/Heat Fs Unit - Carrier MMY-MAP0724FT9UL Service Manual

9-8-2. Troubleshooting when Multiple Indoor Units are Connected to Cool/Heat FS Unit

When multiple indoor units are connected to a Cool/Heat FS unit, it is necessary to set the Code No. [0E]. If
this setting is forgotten, normal operation is impossible.
[Case that Code No. [0E] is set]
All the indoor units which are connected to the identical
Cool/Heat FS unit operate according to the operation
mode of the header unit. The Cool/Heat FS unit keeps the
operation mode until all the indoor units will be
thermostat-OFF.
[Case that Code No. [0E] is not set]
As the Cool/Heat FS unit is controlled by the indoor unit
which is connected with inter-unit wiring, a normal
operation is unavailable.
(In the right figure, operation follows to the indoor unit A.)
If Code No. [0E] is not set, the symptom below appears:
When the following trouble occurred, confirm the Code No. [0E] and then set the Code No. referring to item
"How to connect multiple indoor units to a Cool/Heat FS unit".
[1] [Cool] is set on remote controller
Indoor unit A
1 Cooling operation
2 Cooling operation Cooling thermo-OFF
3 Cooling thermo-OFF
[2] [Heat] is set on remote controller
Indoor unit A
1 Heating operation
2 Heating operation Heating thermo-OFF OFF OFF
3 Heating thermo-OFF
[3] [Cool/Heat Auto] is set on remote controller
Indoor unit A
1 Cooling operation
2 Cooling operation Cooling thermo-OFF
3 Cooling operation
4 Cooling thermo-OFF
5 Cooling thermo-OFF
6 Heating operation
7 Heating operation Heating thermo-OFF OFF OFF
8 Heating operation
9 Heating thermo-OFF
10 Heating thermo-OFF
Cool/Heat FS unit
Indoor unit B
SVS SVSS SVD SVDD
Cooling operation ON
ON
Cooling operation OFF
Cool/Heat FS unit
Indoor unit B
SVS SVSS SVD SVDD
Heating operation OFF OFF
Heating operation OFF OFF
Cool/Heat FS unit
Indoor unit B
SVS SVSS SVD SVDD
Cooling operation ON
ON
Heating operation ON
Cooling operation OFF
Heating operation OFF
Heating operation OFF OFF
Cooling operation OFF OFF
Heating operation OFF OFF
Cooling operation OFF OFF
Cooling/Heating
FS unit
Inter-unit wiring
Connection to remote controller group only is available.
Remote controller individual to each indoor unit is unavailable.
ON OFF OFF Normal operation
ON OFF OFF Normal operation
Cooling mode is not applied to the indoor unit B. (Fan status)
ON OFF OFF
[H06] An error (Low-pressure protective operation) may occur.
ON OFF Normal operation.
ON OFF Normal operation.
ON OFF Normal operation.
ON OFF OFF Normal operation.
ON OFF OFF Normal operation.
ON OFF OFF Indoor unit [L18] error (Cool/Heat FS unit line error)
Heating mode is not applied to the indoor unit B. (Fan status)
ON OFF OFF
[H06] An error (Low-pressure protective operation) may occur.
Heating mode is not applied to the indoor unit B. (Fan or stop status)
ON OFF OFF
[P20] An error (High-pressure protective operation) may occur.
ON OFF Normal operation.
ON OFF Normal operation.
ON OFF Indoor unit B discharges warm wind.
ON OFF Normal operation.
ON OFF Indoor unit B discharges warm wind.
– 201 –
Refrigerant piping
Indoor unit A
Indoor unit B
Remote controller
Symptom
Symptom
Symptom