Mitsubishi Electric LGH-50RSDC-E1 User manual

Warning:
Repair work must be performed by the manufacturer, its service
agent or a similarly qualified person in order to avoid hazards.
LOSSNAY
HANDBOOK
MODEL
LGH-50RSDC-E1 1
July 2019 No. U177-B
Nameplate

Contents
1. Safety precautions ....................................................................... 3
2. Names of components ................................................................ 4
3. Specifi cations ............................................................................... 5
4. Outside dimensions ...................................................................... 6
5. Electrical wiring diagram ............................................................. 7
6. Basic circuit diagrams ............................................................... 8-9
7. Fundamentals of operation ................................................... 10-15
8. Troubleshooting .................................................................... 16-22
9. Overhauling procedures ....................................................... 23-27
10. Parts catalog ......................................................................... 28-34

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Be sure to read the following precautions thoroughly before the maintenance, and then inspect and repair the
product in a safe manner.
The types and levels of danger that may arise if the product is handled incorrectly are described with the warning
symbols shown below.
Warning
Modification is prohibited
Do not modify the unit.
(Failure to heed this warning may result
in electric shock, fire and/or injury.)
Electric shock
If you must inspect the circuitry while the power is
on, do not touch the live parts.
(Failure to heed this warning may result
in electric shock.)
Check insulation
Upon completing repair work, always measure the
insulation resistance. Verify that it is at least 10 MΩ
(with a 500 V DC insulation resistance tester), and
then turn on the power.
(Inadequate insulation may cause electric
shock.)
Incorrect handling of the product may
result in serious injury or death.
Caution Incorrect handling of the product may result in serious injury
or damage to properties including buildings and equipment.
Proper electric work
Use the electric wires designated for electric work,
and conduct electric work in accordance with the
"Electric Installation Engineering Standard", the
"Indoor Wiring Regulations" and the installation
instructions.
(Improper connection or wiring installation
may result in electric shock and/or fire.)
Replace damaged and/or degraded parts
Be sure to replace the power-supply cord and lead
wires in the event that they are damaged and/or
degraded.
(Failure to heed this warning may result
in electric shock and/or fire.)
Use proper parts and tools
For repair, be sure to use the parts listed in the
service parts list of the applicable model and use the
proper tools.
(Failure to heed this warning may result in
electric shock, fire and/or bodily injury.)
Caution against
electric shock
Prohibited
Be sure to follow
this instruction.
Turn off the power supply
Be sure to shut off the power supply isolator before
disassembling the unit for repair.
(Failure to heed this warning may result
in electric shock.)
Make sure that the product operates properly upon completion of repair. Clean the product and the surrounding
area, and then notify the customer of the completion of repair.
Caution for injury
Do not work at a location where you do not have a
sure footing.
(Failure to heed this caution may result in
a fall.) Prohibited
Request for repair
●Inspect the earth condition, and repair it if it is incomplete. Make sure that a power supply isolator or an
overload protection device is installed, if it is not installed, recommend the dealer to install one.
Be sure to follow
this instruction.
Be sure to follow
this instruction.
Be sure to follow
this instruction.
Be sure to follow
this instruction.
Wear gloves
Wear gloves when servicing.
(Failure to heed this caution may result in
injury to your hands from sharp metal or
other edges.) Be sure to follow
this instruction.
1. Safety precautions

─4 ─
2. Names of components
Air filter
(4 filters)
Lossnay core
Maintenance cover
Control box
Air supply fan
(SA fan)
Damper plate
Air exhaust fan
(EA fan)

─ 5 ─
3. Specifi cations
Model LGH-50RSDC-E1 1
Heat exchange system Air-to-air Total heat exchange (sensible heat + latent heat exchange)
Heat exchange element material Partition spacing plate-special treated paper
Cladding Galvanized steel sheet
Heat insulating material Self-extinguishing urethane foam
Motor DC brushless motor. Two units
Blower 220 mm diameter. Centrifugal fan
Filter material Non-woven fabrics fi lter (Gravitational method 82%, EU-G3)
Applicable air condition of setting envi-
ronment
The setting air condition shall be between -10°C to 40°C, 80%RH or less.
Applicable air condition range of outdoor
and indoor
OA temperature shall be -15°C to 40°C, 80%RH or less, with general air
conditioning room environment.
Functions
Lossnay ventilation fi ve speeds / Bypass ventilation (fi ve speeds + power)
Weight 48 kg
Frequency / Power source 50 Hz / Single phase 220 to 240 V
Ventilation mode
Lossnay (Energy recovery) ventilation Bypass ventilation
Fan speed (230 V) 1 2 3 4 5
Power 12345
Current [A] 1.17 0.67 0.35 0.20 0.13 1.80 1.20 0.70 0.35 0.20 0.13
Power Consumption [W] 165 90 41 22 14 265 164 90 40 21 14
Air volume [m3/h] 395 305 215 144 90 468 395 305 215 144 90
[l/s] 110 85 60 40 25 130 110 85 60 40 25
External static pressure [mmH2O] 10.2 6.1 3.1 1.5 0.7 13.8 10.2 6.1 3.1 1.5 0.7
[Pa] 100 60 30 15 7 135 100 60 30 15 7
Temperature exchange effi ciency [%] 77.5 81.5 85.5 88 90 ------
Enthalpy exchange
effi ciency [%]
Heating 71 75 79 82 84 ------
Cooling 68 72.5 77 80.5 83 ------
Noise [dB]
Measured at 1.5 m under the center
of panel in an anechoic chamber
31 26.5 21 18 18 35 31 26.5 21 18 18
Starting current 2.5 A or less
Insulation resistance 10 M
Ω or more (500 V megger)
Dielectric strength AC 1500 V 1 minute

─6 ─
4. Outside dimensions
Unit (mm)

─7 ─
5. Electrical wiring diagram
Thisproductmustbeconnectedtoallpolemainswitchwithatleast3mmdisconnection.

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300 to 340 V DC
(D1)
Fan drive power supply
Reactor
(CN4, CN5)
GND
(C14)
LED 3 (green)
䍃During EA fan operation: lit
䍃During an error: blinking
Fuse
(6.3 A / 250 V)
Motor for
Bypass damper
220 to 240 V AC
(CN3)
Power supply
220 to 240 V 50 Hz
(CN1)
LED 2 (red)
䍃During SA fan operation: lit
䍃During an error: blinking
Transformer
input
(CN2)
Communication
signal between
the circuit boards.
(CN10)
SA fan drive
output
(CN6)
EA fan motor
sensor signal
(CN9)
5 V
0 V
Current waveform of the fan drive output
(Current of each line)
Although the current cycle and value varies
with the operational status, each current waveform
is a sine wave with a phase difference by 120 degrees.
Note) Noise is included in the actual waveform.
Voltage waveform of the fan motor sensor signal
(Voltage between the lead wires of the
connectors 2, 3, 4 and GND)
U Line current V Line current W Line current
U
V
W
The voltage cycle varies with the operational
status (rotational frequency).
Each signal has 50 % duty cycle of H (5 V) and L (0 V),
and there is a phase difference by 120 degrees.
Note) Noise is included in the actual waveform.
●CAUTION
Live parts of the large PCB is not insulated from the power supply.
Even after turning off the power, the capacitors on the circuit boards are still charged.
Wait more than 5 minutes before servicing.
EA fan drive
output
(CN7)
5 V DC
(C14)
SA fan motor
sensor signal
(CN8)
15 V DC
(IC5)
6. Basic circuit diagrams
Circuit board diagrams and check points
(1) Large printed circuit board (PCB) (Left)

─9 ─
(2) Small PCB (right)
Communication
signal between
the circuit boards.
(CN15)
Transformer output
11 V to 20 V AC
(CN14)
5 V DC
(C20)
SW1
12 V DC
(IC6)
GND
(C20)
Thermistor
(return air, outside air)
(CN16)
Damper position detector
(CN17)
䍃during energy recovery ventilation: 12 V DC
䍃during bypass ventilation: 0 V
Fan speed selection
(TM2 1 to 4, TM3 5)
Power bypass
condition selection
(TM3 PB)
During an error: 0 Ω
Normal: Open
(TM4 10, 11)
During operation: 0 Ω
When stopped: Open
(TM4 8, 9)
Ventilation priority
mode selection
(TM3 V)
LED 1 (red)
䍃Normal: lit
䍃During an error: blinking
LED 11 (green)
䍃During trial operation: lit
䍃During an error: blinking
SW2

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7. Fundamentals of operation
Description of the PCB
(1) Air volume control
Fan speed selection
(TM2, TM3) Operation
Air volume
(Reference value under rated static pressure)
(m3/h) (l/s)
All contacts : OFF Stop 0 0
Speed 1 (Contact between 1 and COM) : ON
Running
395 110
Speed 2 (Contact between 2 and COM) : ON 305 85
Speed 3 (Contact between 3 and COM) : ON 215 60
Speed 4 (Contact between 4 and COM) : ON 144 40
Speed 5 (Contact between 5 and COM) : ON 90 25
Power bypass (Contact between PB and COM) : ON 468 130
1 Power bypass will be enabled when any of fan speed contacts (1 to 5) are ON. (The fan will not operate
when only the power bypass contact is turned ON.)
2 It needs 5 seconds to change air volume (including OFF) after the fan speed is selected.
3 When multiple fan speeds are selected simultaneously, the higher fan speed will be performed.
Fan speed fine-tuning
Fan speed can be fine-tuned by the dip switch SW 2 on the circuit board.
SW 2
ON OFF Operation
2
1
or
2
1
All supply air fan speeds are default settings.
2
1
Each of the supply air fan speed settings except
power bypass mode is increased.
2
1
Each of the supply air fan speed settings is
decreased.
4
3
or
4
3
All exhaust fan speeds are default settings.
4
3
Each of the exhaust fan speed settings except
power bypass mode is increased.
4
3
Each of the exhaust fan speed settings is
decreased.
Automatic air volume increasing during bypass setting
Fan speed will automatically increase 1 step higher than its present speed if both conditions are met:
• The dip switch SW 1-7 on the circuit board is ON.
• Operation mode is switched to bypass ventilation from energy recovery ventilation (with a summer criteria)
in automatic ventilation mode.
Example 1 : Speed 3 operation Speed 2 operation
Example 2 : Speed 1 operation Power bypass operation
(If the operation mode is switched to energy recovery ventilation from bypass ventilation, fan speed will
return to its original speed.)