Mitsubishi LGH-50RSDC-E Service Manual
LOSSNAY
HAND BOOK
Model: LGH-50RSDC-E
August 2009 No. U162-A
FOR DEALERS
Nameplate
Repair work should be performed by
the manufacturer, its service agent or
similarly qualified person in order to
avoid hazards.
Contents
1. Safety precautions ................................................................. 3
2. Names of components ......................................................... 4
3. Specifications ....................................................................... 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. Overhaul procedure ....................................................... 23-27
10. Parts catalog ................................................................. 28-34
1. Safety precautions
Please be sure to read the following precautions thoroughly before commencing with the maintenance work, and
conduct the inspection and repair of the product in a safe manner.
The types and levels of danger that may arise if the product is handled incorrectly are described by using the
warning symbols shown below.
Incorrect handling of the product may result in serious injury
Warning
or death.
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.)
Caution for
electric shock
Modification is prohibited
Do not modify the product.
(Failure to heed this warning may result
in electric shock, fire and/or injury.)
Prohibited
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.)
Be sure to follow
this instruction.
Turn off the power supply
Be sure to shut off the power supply isolator before
disassembling the product for repair.
(Failure to heed this warning may result
in electric shock.)
Be sure to follow
this instruction.
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.)
Be sure to follow
this instruction.
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.)
Be sure to follow
this instruction.
Check insulation
Upon completing repair work, always measure the
insulation resistance. Verify that it is at least 10 M
(with a 500 V DC insulation resistance tester), and
then turn on the power.
(Inadequate insulation may cause electric
shock.)
Be sure to follow
this instruction.
Incorrect handling of the product may result in serious injury
Caution
Caution for injury
Do not conduct any work at a location where you do
or damage to properties including buildings and equipment.
Wear gloves
Wear gloves when conducting work.
not have a sure footing.
(Failure to heed this caution may result in
(Failure to heed this caution may result in
a fall.)
Prohibited
injury to your hands from sharp metal or
other edges.)
Be sure to follow
this instruction.
Request for repair
Inspect the grounding, and repair it if incomplete. Make sure that a power supply isolator or an overload
protection device is being installed, if not, recommend the dealer to install one.
Make sure that the product operates properly upon completion of repair. Clean the product as well as the
surrounding area, and then notify the customer of the completion of repair.
3
2. Names of components
Control box
Lossnay core
Damper plate
Maintenance cover
Air filter
(4 filters)
Air exhaust fan
(EA fan)
Air supply fan
(SA fan)
4
3. Specifi cations
Model LGH-50RSDC-E
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 environment
Applicable air condition range of outdoor
and indoor
The setting air condition shall be between -10°C to 40°C, 80%RH or less.
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 220-240 V
Ventilation mode
Fan speed (230 V) 12345
Lossnay (Energy recovery) ventilation
Power
Bypass ventilation
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
3
/h] 395 305 215 144 90 468 395 305 215 144 90
[m
Air volume
[l/s] 110 85 60 40 25 130 110 85 60 40 25
2O] 10.2 6.1 3.1 1.5 0.7 13.8 10.2 6.1 3.1 1.5 0.7
[mmH
External static pressure
[Pa] 100 60 30 15 7 135 100 60 30 15 7
Temperature exchange effi ciency
Enthalpy exchange
effi ciency [%]
Noise [dB]
Measured at 1.5 m under the center
of panel in an anechoic chamber
[%] 77.5 81.5 85.5 88 90 - - - - - Heating 71 75 79 82 84 - - - - - Cooling 68 72.5 77 80.5 83 - - - - - -
31 26.5 21 18 18 35 31 26.5 21 18 18
Starting current 2.5 A or less
Insulation resistance 10 M
or more (500 V megger)
Dielectric strength AC 1500 V 1 minute
5
4. Outside dimensions
6
Unit (mm)
5. Electrical wiring diagram
7
6. Basic circuit diagrams
Circuit board diagrams and check points
(1) Large PCB (printed circuit board) (Left)
5 V DC
(C14)
EA fan drive
output
(CN7)
GND
(C14)
SA fan drive
output
(CN6)
EA fan motor
sensor signal
(CN9)
SA fan motor
sensor signal
(CN8)
LED 3 (green)
䍃During EA fan operation: lit
䍃During an error: blinking
LED 2 (red)
䍃During SA fan operation: lit
䍃During an error: blinking
Communication
signal between
the circuit boards.
(CN10)
Transformer
input
(CN2)
Motor for
Bypass damper
220-240 V AC
(CN3)
300-340 V DC
(D1)
Fan drive power supply
15 V DC
(IC5)
Current waveform of the fan drive output
(Current of each line)
Reactor
(CN4, CN5)
Voltage waveform of the fan motor sensor signal
(Voltage between the lead wires of the
Fuse
(6.3 A / 250 V)
connectors 2, 3, 4 and GND)
U Line current V Line current W Line current
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.
CAUTION
●
5 V
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.
0 V
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.
Power supply
220-240 V 50 Hz
(CN1)
8
(2) Small PCB (right)
Transformer output
11 V to 20 V AC
(CN14)
SW1
Communication
signal between
the circuit boards.
(CN15)
Thermistor
(return air, outside air)
(CN16)
LED 1 (red)
12 V DC
(IC6)
Damper position detector
(CN17)
䍃during energy recovery ventilation: 12 V DC
䍃during bypass ventilation: 0 V
GND
(C20)
5 V DC
(C20)
䍃Normal: lit
䍃During an error: blinking
SW2
LED 11 (green)
䍃During trial operation: lit
䍃During an error: blinking
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)
Power bypass
condition selection
(TM3 PB)
Fan speed selection
(TM2 1-4, TM3 5)
9
7. Fundamentals of operation
Description of the PCB
(1) Air volume control
Fan speed selection
(TM2, TM3)
Operation
(Reference value under rated static pressure)
(m3/h) (l/s)
All contacts : OFF Stop 0 0
Air volume
Speed 1 (Contact between 1 and COM) : ON
395 110
Speed 2 (Contact between 2 and COM) : ON 305 85
Speed 3 (Contact between 3 and COM) : ON 215 60
Running
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 fi ne-tuning
Fan speed can be fi ne-tuned by the dip switch SW 2 on the circuit board.
ON OFF Operation
2
1
or
All supply air fan speeds are default settings.
Each of the supply air fan speed settings except
power bypass mode is increased.
Each of the supply air fan speed settings is
decreased.
or
All exhaust fan speeds are default settings.
Each of the exhaust fan speed settings except
power bypass mode is increased.
Each of the exhaust fan speed settings is
decreased.
SW 2
2
1
2
1
2
1
4
3
4
3
4
3
4
3
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.)
─10─
Cold region operation mode
When using the unit in cold region, set the air supply (SA)fan in the SA intermittent operation mode to prevent the energy recovery core from freezing. The fan operation is based on the measured outside air (OA)
temperature as below.
Operation mode OA temperature SA fan EA fan
Normal -10°C < OA temperature Continuous running
1
2
SA intermittent -15°C <OA temperature -10°C
SA stopped OA temperature -15°C Repeat 55 min. stop / 5 min. running
1 The operation mode will be decided 5 minutes after the normal operation during startup.
2 The running condition does not change while the SA fan stops or 1 minute after startup. (OA temperature
is voided.)
3 When the switch SW 1-3 is on, the EA fan operates at fan speed 5 during 55-minute stop of the SA fan.
Repeat 10 min. stop / 60 min. running
1 2
1 2
Continuous running
Continuous running
Continuous running
3
(2) Damper motor control
Automatic ventilation mode
Automatic ventilation algorithm patterns are switched by the OA • RA (return air) thermistor and function setting switch SW 1-6.
Function setting switch SW1-6
OFF (factory setting) 17°C or higher Automatic ventilation pattern 1 (chart 1)
ON 28°C or higher Automatic ventilation pattern 2 (chart 2)
Power bypass mode
When turning on the TM3 PB contact with any fan speed contacts (1 to 5) on, operation mode will be
switched to bypass ventilation. Then, fan speed will be also increased to Power bypass speed.
Ventilation priority mode
When turning on the TM3 V contact with any fan speed contacts (1 to 5) on, operation mode (energy recovery or bypass) can be fi xed by the function setting switch SW 1-4. (Fan speed will not be changed in the
bypass ventilation mode.)
Function setting switch SW1-4 Ventilation priority mode
OFF (factory setting) Bypass ventilation fi xed
ON Energy recovery ventilation fi xed
Prohibition of the bypass ventilation
In case of the situations below, bypass ventilation will be disabled, and energy recovery ventilation setting
will be activated.
a. OA temperature 8°C (for dew condensation prevention)
b. OA • RA thermistor failure.
OA temperature criteria
in the summer season
Automatic ventilation algorithm
─11─
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