Mitsubishi Heavy Industries MHI FDU71VNXVF1 Technical Manual page 257

(17) Plural unit control – Control of 16 units group by one remote control
(a)
Function
One remote control switch can control a group of multiple number of unit (Max. 16 indoor units). "Operation mode"
which is set by the remote control switch can operate or stop all units in the group one after another in the order of unit
(1)
No. . Thermostat and protective function of each unit function independently.
Notes (1) Unit No. is set by SW2 on the indoor unit control PCB. Unit No. setting by SW2 is necessary for the indoor unit only.
SW2: For setting of 0 – 9, A – F
(2) Unit No. may be set at random unless duplicated, it should be better to set orderly like 0, 1, 2..., F to avoid mistake.
(b) Display to the remote control
(i) Center or each remote control basis, heating preparation: the youngest unit No. among the operating units in the
remote mode (or the center mode unless the remote mode is available) is displayed.
(ii) Inspection display, filter sign: Any of unit that starts initially is displayed.
(iii) Confirmation of connected units
1)
In case of RC-E5 remote control
Pressing "AIR CON No." button on the remote control displays the indoor unit address. If " ▲ " " ▼ " button is
pressed at the next, it is displayed orderly starting from the unit of youngest No.
2)
In case of RC-EX1A remote control
If you touch the buttons in the order of "Menu" → "Next" → "Service & Maintenance" → "IU address" on the
TOP screen of remote control, the indoor units which are connected are displayed.
(iv) In case of anomaly
1)
If any anomaly occurs on a unit in a group (a protective function operates), that unit stops with the anomalous
stop but any other normal units continue to run as they are.
2)
Signal wiring procedure
Signal wiring between indoor and outdoor units should be made on each unit same as the normal wiring. For
the group control, lay connect with sires wiring between rooms using terminal blocks (X, Y) of remote control.
Connect the remote control communication wire separately from the power supply wire or wires of other
electric devices (AC220V or higher).
(18) High ceiling control
When sufficient air flow rate cannot be obtained from the indoor unit which is installed at a room with high ceiling, the air flow
rate can be increased by changing the fan tap. To change the fan tap, use the indoor unit function "FAN SPEED SET" on the
wired remote control.
Fan tap
STANDARD
FAN SPEED SET
HIGH SPEED1, 2
Notes (1) Factory default is Standard.
(2) At the hot-start and heating thermostat OFF, or other, the indoor unit fan is operated at the low speed tap of each setting.
(3) This function is not able to be set with wireless remote controls or simple remote control (RCH-E3)
(19) Abnormal temperature thermistor (return air/indoor heat exchanger) wire/short-circuit detection
(a) Broken wire detection
When the return air temperature thermistor detects -20°C or lower or the heat exchanger temperature thermistor detect
-40°C or lower for 5 seconds continuously, the compressor stops. After a 3-minute delay, the compressor restarts but,
if it is detected again within 60 minutes after the initial detection for 6 minutes continuously, stops again (the return air
temperature thermistor: E7, the heat exchanger temperature thermistor: E6).
(b) Short-circuit detection
If the heat exchanger temperature thermistor detects 70°C or higher for 5 seconds continuously at 2 minutes and 20
seconds after the compressor ON during cooling operation, the compressor stops (E6).
Outdoor unit
Signal wiring
between outdoor unit
and indoor units
0 1
Indoor unit
R
Remote control
- -
PHi - Hi - Me - Lo
PHi - PHi - Hi - Me
2 3
Remote control wiring
Indoor unit airflow setting
- - - -
Hi - Me - Lo Hi - Lo
PHi - Hi - Me PHi - Me
256
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'12 • PAC-T-178
F
-
Hi - Me
PHi - Hi