Page 1
SERVICE MANUAL
PTACSERIES
7,000-15,000 BTU/H
Page 2
CONTENTS
1. Precaution
1-3
1.1 Safety Precaution
1.2 Warning
2. Dimensions
3. Unit Components
4. Installation Details
4.1 How to Install Unit
4.2 Care and Cleaning
4.3 Other Installations
5. Functions and Control Panel
6. Refrigerant Cycle Diagram
7. Electronic Function
7.1 Terms and Definitions
7.2 Electric Control Working Environment
7.3 Protection Function
7.4 Operation of Fan Motor
7.5 Operation of Compressor
7.6 DIP Switches and Jumper Selection
8. Operations Characteristics
8.1 Cooling Operation
8.2 Heating Operation
9. Power Connection Options
10. Troubleshooting
10.1Error Display
10.2Troubleshooting
1
1-3
3
4
5-15
5-7
7-8
9-15
16-20
21
21-25
21
22
22
22-23
24-25
25
25
25
25
25
26-27
28-33
28
28-33
Page 3
www.mideaaircon.com 1
1.
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Precaution
1.1
Safety Precaution
To prevent personal injury and/or property damage, follow the instructions below.
Failure to follow correct procedure may result in personal inj ury, death, and/or property damage. Before
servicing unit, read this service manual.
1.2
Warning
INSTALLATION
To reduce the risk of fire or explosion, electric shock, personal injury, death, product failure, or property damage during the installation process, read and follow the warnings listed below.
Do not use a defective or underrated circuit breaker. Use a dedicated circuit on this appliance.
For electrical work, contact the dealer/seller, a qualified electrician, or an authorized service center.
Do not disassemble or repair the product.
Ground the product.
Securely install the panel and cover of control box.
Avoid improper wiring or installation.
Use the correctly rated breaker and fuse.
Do not modify or extend the power cable.
Do not install, remove, or reinstall the unit unaccompanied.
Be careful when unpacking and installing around exposed sharp edges, especially the casing edges
and the fins on the condenser and evaporator.
For installation, always contact the dealer or an authorized service center.
Do not install the product on a defective installation stand.
Be sure the installation area does not deteriorate with age to avoid the base collapsing.
Do not let the air conditioner run for a long period of time when there is high humidity and a door or
window is left open. Moisture may condense and wet or damage furniture.
Do not pull out or damage the power cord during operation.
Do not place anything on the power cable.
Do not plug or unplug the power plug during operation.
Do not touch/operate the product with wet hands.
Do not place a heater or other appliance near the power cable.
Do not allow water get into the electric parts.
Do not store or use flammable gas near the product.
Do not use the product in a confined space for a long period of time to avoid oxygen deficiency.
If a flammable gas leaks, turn off the gas and open a window for ventilation before turning this
product on. Do not use the telephone or turn switches on or off.
If strange sounds or smoke come from product, turn the breaker off or disconnect from power
Page 4
www.mideaaircon.com 2
supply.
●
Stop operation and close window during a storm. If possible, remove product from window.
●
Do not open the product’s inlet grill while in operation. If the unit has an electrostatic filter, do not
touch it.
●
Avoid having water enter the unit.
●
If the product becomes soaked, flooded, or submerged in water, contact an authorized service
center.
●
Ventilate the product from time to time when operating it near a stove or other appliance.
●
Turn the main power off when cleaning or troubleshooting the product.
●
If the product will not be in use for a long period of time, disconnect it from the power supply or turn
off the breaker. An unintended operation may occur.
●
Ensure that no one can step on or fall onto the outdoor unit.
CAUTION
To reduce the risk of injury or property damage after installing product, read and follow the warnings listed below.
●
Always check for gas (refrigerant) leakage after installing or repairing. Low refrigerant levels may
cause product failure.
●
Install drain hose to ensure water drains away properly. A bad connection may cause water
leakage.
●
Keep unit levelled when installing to avoid vibration or water leakage.
●
Do not install product where noise or hot air from the outdoor unit can bother others or damage
property.
●
In order to avoid personal injury, use two or more people to lift and transport product.
●
Do not install the product where it will be directly exposed to ocean breeze (salt spray). It may
cause corrosion, which, particularly on the condenser and evaporator fins, could cause product
malfunction or inefficient operation.
OPERATIONAL
To reduce the risk of fire or explosion, electric shock, personal injury, health issues, product failure, or property damage while the product is in operation, read and follow the warnings liste d below.
●
Do not sit in the draft or expose skin directly to cool air for long periods of time.
●
Do not use unit for other purposes, such as preserving foods, works of art, etc., not intended for this
product. It is a consumer air conditioner, not a refrigerating system.
●
Do not block the inlet or outlet of airflow.
●
Use a soft cloth to clean. Do not use harsh detergents, solvents, etc.
●
Do not touch the metal parts of the product when removing the air filter. They are sharp.
●
Always insert the filter securely. Clean the filter every two weeks or, if necessary, more since a dirty
filter reduces product efficiency and could cause product malfunction or damage.
●
Do not insert hands or other object through air inlet or outlet. There are sharp, moving parts inside.
Page 5
www.mideaaircon.com 3
●
Dimensions
W x H x D (inches)
Dimension 1
No sleeve, rear grille, or rear net
Dimension 2
Includes sleeve with no rear grille and rear net
Dimension 3
Includes sleeve and rear net
Dimension 4
Includes sleeve, rear net, rear grille
Do not drink the water drained from the product. It is unsanitary.
●
Use a firm stool or ladder when cleaning the product.
●
Replace all batteries in the remote control with new ones. Do not mix old and new batteries.
●
Do not recharge or disassemble the batteries or dispose of them in a fire.
●
If the liquid from the batteries touches exposed skin and/or gets on clothing, wash with clean water.
Do not use the remote if the batteries have leaked.
2.
Dimensions
42 x 15.9 x 20.9
42 x 16 x 22.8
42 x 16 x 23.1
42 x 16 x 23.9
Page 6
www.mideaaircon.com 4
3.
Unit Components
Decomposition
Figure
Page 7
www.mideaaircon.com 5
4.
Installation Details
4.1
How to Install Unit
Page 8
www.mideaaircon.com 6
PREPARATION OF SLEEVE ASSEMBLY
Dimensions of air conditioner
(optional)
• For an existing sleeve, measure the wall sleeve
dimensions.
• Install the new air conditioner according to
these installation instructions to achieve the
best performance. All wall sleeves used to
mount the new air conditioner must be in good
structural condition and have a rear grille that
securely attaches to the sleeve or the overhang
of the sleeve to secure the new air conditioner.
• To avoid vibration and noise, make sure the unit
is installed securely and firmly.
• When installing the sleeve, make certain there
is nothing within 20 inches of the back that
would interfere with heat radiation and exhaust
airflow. (See Fig. 2)
w
Fig. 2
• Refer to the installation instruction of sleeve
assembly for more details.
UNIT INSTALLATION
• Carefully remove shipping tapes from the front
panel. (See Fig. 3)
• Remove the front panel (see Fig. 4) by pulling
out the bottom to release the tabs (A). Then lift
up (B).
• Remove the shipping screw from the vent door.
(See Fig. 5)
• Rotate the vent control lever to either open or
close the vent door. (See Fig. 6)
Page 9
www.mideaaircon.com 7
UNIT INSTALLATION (CONTINUED)
4.2
Care and Cleaning
•
Keep unit levelled when lifting and sliding it
into wall sleeve. Once it is firmly against front
of wall sleeve, secure with 4 screws and
washers (supplied in the Sleeve Assembly)
through the unit overhang holes. (See Fig. 7
and Fig. 8)
•
Reinstall front panel. (See Fig. 9) Place tabs
over top rail (A). Push inward at bottom until
panel snaps into place (B).
•
If unit is installed where condensation
drainage can drip in an undesirable location,
an accessory drain kit should be installed and
connected to drain system.
FRONT PANEL AND CASE
Turn unit off and disconnect from power supply.
To clean, use water and a mild detergent. Do not
use bleach or abrasive materials. Some
commercial cleaners may damage the plastic
parts.
OUTDOOR COIL
Coil on outdoor side of unit should be checked
regularly. Unit will need to be removed to inspect
dirt build-up that will occur on the inside of the
coil. If clogged with dirt or soot, coil should be
professionally cleaned. Clean inside and outside
of outdoor coils regularly.
NOTE: Never use a high-pressure spray on coil.
Page 10
www.mideaaircon.com 8
!
CAUTION
!
CAUTION
damage to unit.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Airflow restriction may cause damage to the unit.
• The most important thing do to in order to
maintain unit efficiency is to clean the filters
once every two weeks as required.
• Clogged filters reduce cooling, heating and
airflow.
• Keeping filters clean will:
o Decrease cost of operation,
VENT DOOR FILTER
IMPORTANT: Turn unit off
before cleaning
• If the vent door is open, gaining access
requires removing the unit from the wall
sleeve. Clean the vent filter twice a year or as
required.
• Make sure to remove the shipping screw from
the vent door. (See Fig.5)
• Rotate the vent control lever to open the vent
door. (See Fig.6)
• Remove the four screws from the vent door
filter. (See Fig.12)
• Pull out the vent door steel wire from the hole
of the vent door, then take off the vent door
and filter. (See Fig.12)
o Save energy,
o Prevent clogged indoor coil, and
o Reduce risk of premature component failure.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in
equipment damage or improper operation.
Do not operate unit without filters in place. If a
filter becomes torn or damaged, it should be
replaced immediately.
Operating without filters or with damaged ones
will allow dirt and dust to reach indoor coil and
will reduce cooling, heating, airflow, and
efficiency of unit. Airflow restriction may cause
• Clean the filter. Dry thoroughly before
replacing.
• Replace the vent door, reinstall the four
screws.
• Reinsert the vent door steel wire.
• To clean air filters:
o Vacuum off heavy soil,
o Run water through filter, and
o Dry thoroughly before replacing.
Page 11
www.mideaaircon.com 9
4.3
Other Installations
Optional Wired/Wireless Digital Wall Stat and EMS systems.
DIP SWITCH 24V WIRED CONTROL
Digital Wired/Wireless Wall Stat Terminal
Page 12
www.mideaaircon.com 10
Thermostat Installation
Controller for Wired
Stat
Hook up wall stat
connector with the digital
stat controller circled in
red.
24V Controller for PRO1 wireless or other
wired modules.
To install wired thermostat, plug it in directly to the unit as shown below:
Page 13
www.mideaaircon.com 11
Hook up wall stat connector to the
unit as shown in the image.
It is advisable to affix wall stat wire
with tape to avoid any damage
while installing the unit.
Page 14
www.mideaaircon.com 12
PRO1 Wireless and Wired Digital Wall Stat Configuration
Follow the steps below:
1.
Power OFF the unit.
2.
Turn OFF all the DIP switches by pushing them down.
3.
Turn ON S3—the second switch on the second block from right—by pushing it up. Circled in red
below.
4.
Detach the controller cover.
Page 15
www.mideaaircon.com 13
5.
Connect the wireless or wired module with controller. Use the table below as guidance.
Page 16
www.mideaaircon.com 14
6.
Jump the connection between Heat 1 and Heat 2 as shown below.
7.
After connecting the stat with unit, apply double-sided tape on the back of wireless module.
Page 17
www.mideaaircon.com 15
8.
Stick the module to unit as depicted below.
9.
Set the thermo s tat to OFF.
10.
Set CO to b on thermostat by following the procedure below:
Press and hold + and - on thermostat until it displays CA 1. T hen press them again to get either
CO b or CO 0.
•
If CO 0 is displayed, then press + to change it to CO.
•
If CO b is displayed, then wait for the thermostat to return to temperature screen.
11.
Replace the cover and assemble the unit.
12.
Turn ON the unit and allow 3 minutes for response time.
Page 18
www.mideaaircon.com 16
5.
Functions and Control Panel
The controls featured in this manual are found in many different models. There may be slight variations.
POWER
Press the POWER button to turn the unit on or off. When the unit is on, the power indicator light will be
green. When the unit is off, the light will go out.
MODE
Push this button to cycle through the modes COOL, HEAT, and FAN. The green indicator light beside a
mode will illuminate, identifying which one is selected. The range of temperature setting is 62°F – 86°F.
●
COOL: Cooling begins automatically when the ambient temperature is above the set point and
stops when the ambient temperature is 4°F below the set point. However, the compressor will run
at least 5 minutes in COOL mode before stopping. The fan runs in continuous mode.
●
HEAT: For heat pump models, the unit can alternate to run between reverse cycle heat mode and
electric heater mode, according to the difference between the set temperature and the ambient
temperature. The fan motor cycles on and off with the compressor and electric heater.
●
FAN: Fan operation only without heating and cooling.
NOTE: The reverse cycle and electric heater cannot run at the same time. It is normal for the reverse
cycle heat mode not to operate in the following cases:
1.
When the outdoor temperature is lower than 40°F or the ambient temperature falls 8°F below the
set point temperature.
2.
There i s a 3-minute minimum compressor run time at any setting to prevent short cycling. The
indoor fan motors start and stop before and after the compressor cycles off.
3.
When frost builds up to the evaporator coils, the unit will defrost automatically and the compressor
will cycle off.
UP/DOWN BUTTONS (▲ / ▼)
Push the UP or DOWN button to increase or decrease the set temperature in cooling or heating mode.
The temperature can be set by increments of 1°F. The setting temperature appears in the display.
NOTE: Press and hold ▲ and ▼ buttons simultaneously for 3 seconds to alternate the temperature
display between °C and °F scale.
Page 19
www.mideaaircon.com 17
FAN
Push this button to change the fan speed to HIGH, MED, or LOW.
DISPLAY
Shows the set temperature in °C or °F. While on FAN-only mode, it shows the ambient temperature.
Control codes:
• LC: Pads on the control panel are not available. The unit can be set by using wire controller only.
Note: When receiving the wired remote control signal display LC. Or when wired remote control
signal is not received within the panel key operation for 5 seconds to display LC
• FC: Front desk control.
Error codes:
• AS: Open or short circuit of ambient temperature sensor (T1).
• ES: Open or short circuit of evaporator temperature sensor (T2).
• CS: Open or short circuit of condenser temperature sensor (T3).
• OS: Open or short circuit of outside temperature sensor (T4).
• HS: Open or short circuit of exhaust temperature sensor (T5 or T6).
Page 20
www.mideaaircon.com 18
Other codes:
• LO: Room temperature is lower than 32°F.
• HI: Room temperature is higher than 99°F.
• E4: Communication failure between main control board and display
board.
• LE: Wire Controller mode failure
DIP Switches
Configurations and functions of each DIP switch position are explained below.
Page 21
www.mideaaircon.com 19
DIP Switches Configurations
No. UP (O N) DOWN (OFF) Remarks
S1
S2
S3
S4*S5
S6
S7
S8
S9
Electric heat only Electric heat and pump heat For heat pump unit only.
Temperature Display in °C Temperature Display in °F
Wall thermostat enable Control panel enable
UP*UP: 61°F – 86°F
UP*DOWN: 65°F – 78°F
DOWN*UP: 63°F – 80°F
DOW N*DOWN: 68°F – 75°F
Fan continuous run for heating Fan cycle for heating
Fan continuous run for cooling Fan cycle for cooling
Low temp. protection enable
Use some types of wall
thermostat
Low temp. protection disable
Use PTAC other wall
thermostat
Two configurations
(S4*S5) combine to
select set point range.
Consult with the sales
agency or manufacturer
for details.
NOTE: On heating mode, the temperature setting can’t be higher than 84°F.
• Electric Heat Only (for heat pump unit only): This setting is typically used for emergency
heating.
• Wall Thermostat Enable: A wired wall thermostat can be connected to the unit. To connect a
wall thermostat to the unit, this DIP switch must be moved to the Wall Thermostat Enable position
in order for the wall thermostat to function.
• Set-point Temperature Limits: Provides a restricted range of temperature control.
• Heat and Cool Fan CON/CYC DIP switches: Allows the fan to operate in continuous or cycle
mode while the unit is in heating or cooling mode.
o Continuous (CON): Allows fan to r un cont inuously, circ ulat ing air even when t he t emperature
setting has been satisfied. This switch helps to maintain the ambient temperature closer to the
thermostat setting.
o Cycle (CYC): This setting allows the fan to cycle on and off with the compressor or electric
heater. The fan stops a short time after the set point is reached.
Functions for Front desk switch panel and Wire Controller
• Front desk switch panel: If an ON/OFF switch is connected to the ports, the A/C unit can be
turned off with it. The LED display on the unit will show FC.
• Wired controller: The LED display will show LC (reserved) if a wired controller is connected. If the
communication portal is one way, the buttons on the control panel will be invalid.
Note: This wired controller is optional, and it is connected to the switchboard.
Page 22
www.mideaaircon.com 20
FRONT DESK SWITCH PANEL
AWG WIRE SIZE NO.
MAX. LENGTH (FT.)
24
400
22
600
20
900
18
1500
16
2000
ROOM 100 ROOM 101 ROOM N
FIELD-SUPPLIED
24V
TRANSFORMER
(SEE NOTE 1)
Black
PTAC #1 PTAC #2 PTAC #N
White
Black
White
Black
White
SUGGESTIONS:
1. To size a transformer, use the following equation:
Quantity of PTAC units x 1 VA = Transformer Size (VA)
Example: 110 PTAC units x 1 VA = 110 VA Transformer
2. Below are the American Wire Gauge (AWG) recommended sizes:
Page 23
www.mideaaircon.com 21
6.
LIQUID SIDE
CHECK VALVE
(Heating Model only)
CAPILIARY TUBE
HEAT
EXCHANGE
(EVAPORATOR)
HEAT
EXCHANGE
(CONDENSER)
GAS SIDE
ACCUMULATOR
REVERSING VALVE
(Heating Model only)
COMPRESSOR
COOLING
HEATING
Refrigerant Cycle Diagram
The figure below is a brief description of the important components and their function in the
refrigeration system.
This will help to explain the refrigeration cycle and the flow of the refrigerant in the Heat Pump Cycle.
7.
Electronic Function
7.1
Terms and Definitions
• T1: Temperature of indoor ambient.
• T2: Temperat ure of evaporator.
• T3: Temperat ure of condenser.
• T4: Temperature of outdoor ambient.
• TS: Set temperature.
• DAT: Discharge air temperature.
• (T5) DAT: Discharge air temperature (T6).
Page 24
www.mideaaircon.com 22
7.2
•
•
•
Electric Control Working Environment
Input voltage: 265V, 60Hz; 230/208V, 60Hz
7.3
Protection Function
The compressor protection functions with a delay of 3
minutes.
Sensor protection at open or short circuit of sensor.
Evaporator anti-freezing protection in cooling mode.
7.4
Operation of Fan Motor
7.4.1 Fan motor is on when compressor is on. Fan motor is off when compressor is off.
(Except the T2 high Temp. protection.)
If there is only one speed for the fan motor, use the high speed instead of the low speed.
7.4.2 The fan motor operating in cooling only mode (see Fig. A).
T4 Operate on high speed
T01
T02
Operate on low speed
Fig. A
• If T4>T01 and lasts for 1 minute, the fan motor will operate at high speed.
• If T4<T02 and lasts for 1 minute, the fan motor will operate at low speed.
• If T02≤T4≤T01:
o If fan motor was initially off, it will operate at high speed.
o If fan motor was initially on, it will keep operating at initial speed.
Page 25
www.mideaaircon.com 23
7.4.3 The fan motor operating in heat pump and cooling mode (see Fig. B).
T4 Operate on low speed
T03
T04
Operate on high speed
Fig. B
• If T4≥T03 and lasts for 1 minute, the fan motor will operate at low speed.
• If T4≤T04 and lasts for 1 minute, the fan motor will operate at high speed.
• If T04<T4<T03:
o If fan motor was initially off, it will operate at high speed.
o If fan motor was initially on, it will keep operating at initial speed.
7.4.4 The high temperature protection of evaporator at heat pump and cooling mode.
• If T2>TE7, the unit will turn the protection of compressor off, and stop this protection when
T2≤TE9.
• If T2>TE8, it will turn the protection of fan motor off, and stop this protection when T2≤TE9.
• If T2>TE15, fan motor will operate at low speed by force, then stop, and determine the high or low
speed according to T4.
6.4.5 At the fan only mode, the fan will keep operating and the compressor/fan motor/heater
will stop operating.
Page 26
www.mideaaircon.com 24
7.5
Operation condition for
heater or compressor
(T1-Ts) °F
Heater (compressor) off
2 -2
Heater (compressor) on
Operation condition
(T1-Ts) °F
Compressor on
+0 -4
Compressor off
Operation of Compressor
7.5.1 The compressor operating in cooling mode.
T1≥Ts compressor is on
T1≤Ts-4°F compressor is off
7.5.2 The compressor operating at heating mode.
There are two heating modes: (1) heat pump and (2) electric heater. The electrical heater or
compressor will activate by sensing difference between set point and ambient temperature.
7.5.2.1 The electric heater operation.
• If T1<2°F less than Ts and the fan motor is operating, 3 seconds later the heater will turn on and
operate at low speed. After 30 seconds, it will change to the set speed. If the DAT temperature
is higher than the protection temperature when the heater is operating, the fan motor will turn off
automatically.
• If T1≥2°F more than Ts and the heater is off, and the fan motor will continue working at set
speed. If the DAT temperature is lower than the protection temperature and the fan motor has
been operating for more than 15 seconds, then the fan motor will turn off. If the T2 protection is
triggered, the fan motor will not turn on.
Page 27
www.mideaaircon.com 25
7.5.2.2 The heat pump operation.
The heat pump’s operation mode correlates to whether the compressor is operating. When the
compressor is on and the electric heater is off, the fan motor will operate according to the anti-cold
wind of heat pump. The four-way valve is always on. If T1<Ts-2°F, the compressor is on. If
T1≥Ts+2°F, the compressor will be off. The fan motor also works in correlation to whether the
compressor is in operation. If T2>TE7, the compressor will turn off. When the DAT protection is
triggered, it will prevent the compressor from operating.
7.6
DIP Switches and Jumper Selection
Note: This switchboard is opt ional.
8.
Operation Characteristics
8.1
Cooling Operation
8.2
Heating Operation
Page 28
www.mideaaircon.com 26
9.
Power Connection Options
Appropriate power cord accessory kit is determined by the voltage and amperage of the branch circuit.
The unit does not come with a power cord (or hardwire kit). An accessory power cord must be ordered
to connect the unit to an outlet. If the unit is to be hardwired, an accessory hardwire kit must be
ordered.
NOTE: For 265V units, if a power cord is selected, it must plug into the 265V subbase accessory.
Cord-connected Units
The 240V field supplied outlet must match the plug for the standard 208/230V units and be within reach
of the service cord. The standard cord-connected 265V units require an accessory electrical subbase
for operation.
Power Cord Protection
The power cord for 230/208v units provide power cord fire protection. The unit’s power automatically
disconnects when unsafe conditions are detected. Power to the unit can be restored by pressing the
reset button on plug. Upon completion of unit installation for 230/208V models, an operational check
should be performed using the TEST/RESET buttons on the plug.
NOTE: The 265V models do not incorporate this feature as they require use of the electrical subbase
accessory. Our subbase accessory is being developed.
The appearance of the power plug will differ depending on the supplier.
Page 29
www.mideaaircon.com 27
Power Connection Chart
CODE OF POWER SUPPLY KIT
UNIT MODEL
15A 20A 30A
208 / 230 V 208 / 230 V 208 / 230 V
MWDUP-07AEN1-MK9
MWDUP-07EEN1-MK9
MWDUP-09AEN1-MK3
MWDUP-09EEN1-MK3
MWDUP-12AEN1-MJ5
MWDUP-12EEN1-MJ7
MWDUP-15AEN1-MI6
MWDUP-15EEN1-MI5
MWDUP-07AEN1-UK9
MWDUP-07EEN1-UK9
MWDUP-09AEN1-UK3
MWDUP-09EEN1-UK3
MWDUP-12AEN1-UJ5
MWDUP-12EEN1-UJ7
MWDUP-15AEN1-UI6
6-15P(15A / 240V )
6-20P(20A / 240V )
6-20P(20A / 240V )
6-30P(30A / 240V )
265 V 265 V
7-20P(20A / 277V )
7-30P(30A / 277V )
MWDUP-15EEN1-UI5
MWEUP-09EEN1-BK3
MWEUP-12EEN1-BJ7
115V
5-15P(15A / 120V )
Page 30
www.mideaaircon.com 28
Check the connection
10.
Codes
Explanations
AS
Open or short circuit of T1 temperature sensor
ES
Open or short circuit of T2 temperature sensor
CS
Open or short circuit of T3 temperature sensor
OS
Open or short circuit of T4 temperature sensor
HS
Open or short circuit of T5 or T6 temperature sensor
Lo
Temperature is lower than display range (32°F)
HI
Temperature is higher than display range (99°F)
E4
Communication malfunction between main control board and display board
LE
Drive-by-wire control failure
Wiring mistake
Troubleshooting
10.1
10.2
Error Display
Troubleshooting
10.2.1
Open circuit or short circuit of temperature sensor diagnosis and solution (AS/E5/CS/oS/HS).
Error Code:
AS/ES/CS/OS/HS
Malfunctioning conditions:
Possible causes:
If the sampling voltage is lower than 0.06V or higher than
4.94V, the LED will display the failure.
●
●
Faulty sensor
●
Faulty PCB
Troubleshooting:
between temperatur e
sensor and PCB. It is
properly connected?
Yes
Measure the resistance
value of the sensor.
No
No
Correct the connection.
Replace the sensor.
Yes
Replace indoor main PCB.
Page 31
www.mideaaircon.com 29
T5/T
T4
T3
T2
T1
Page 32
www.mideaaircon.com 30
10.2.2
Error Code:
Main control board does not receive feedback from display
Wiring error
Faulty main control board
Check signal wire between the
display board and main board.
Is it properly connected?
No Yes
Reconnect and retry. Is
error still showing?
No Yes
Replace display board. Is
error still showing?
No Yes
Trouble is fixed.
Communication malfunction between main control board and display board (E4).
E4
Malfunctioning conditions:
Possible causes:
board during 120 seconds.
●
●
Faulty display board
●
Troubleshooting:
Communication malfunction
between main control board and
display board
Replace the main
control board.
Page 33
www.mideaaircon.com 31
10.2.3
1. Electric heating signal or compressor signal is on, but fan
Wiring error
Wire controller doesn’t match
DIP Switch Terminal
Designation
24V Controller
FC(L)
Front desk control terminal L
FC(N)
Front desk control terminal N
LOW-FAN
Low fan speed
GL
HI-FAN
High fan speed
GH
4-WAY
4-way valve(for heat pump model)
B HEAT2
Electrical heater 2
W
HEAT1
Electrical heater 1
(W)
COMP
Compressor
Y
24V(N)
24VAC terminal N COM
C 24V(L)
24VAC terminal L
R
Drive-by-wi re contr oller failure (LE).
Error Code:
LE
signal is off.
Malfunctioning conditions:
2. Electric heating and compressor signals are on, but 4-way
valve signal is off.
3. Cooling only models have heating signal, or the 4-way
valve and compressor signals are on at the same time.
●
Possible causes:
●
Faulty wire controller
●
Troubleshooting:
Page 34
www.mideaaircon.com 32
Possible Causes
Solutions
UNIT DOES NOT START
Unit is unplugged.
Unit is in a protection mode.
Check that plug is securely connected to outlet.
Turn unit on (bottom right button on keypad).
UNIT NOT COOLING/HEATING ROOM
Compressor is in a time delay.
Make sure curtains, blinds, and/or furniture are not restricting or
DISPLAY HAS STRANGE NUMBERS/
CHARACTERS ON IT
The unit may be in a protection mode.
The unit may have been set for °C instead of °F.
UNIT MAKING NOISES
Clicking, gurgling, and whooshing noises are normal during
operation.
WATER DRIPPING OUTSIDE
If a drain kit has not been installed, condensation runoff during hot
check gaskets and fittings around drain for leaks and plug them.
WATER DRIPPING INSIDE
Wall sleeve must be installed correctly for proper drainage of
necessary adjustments.
ICE OR FROST FORMS ON INDOOR COIL
When outdoor tem perature is approx im ately 55°F or belo w, fr ost
Remove and clean filters.
COMPRESSOR PRO TECTION
Random Compressor Restart: Whenever the unit is plugged in or
compressor run time of 3 minutes.
Blown fuse.
Tripped circuit breaker.
Unit is turned off.
Note: Plug has a test/reset button on it. Make sure that the plug
has not tripped.
Replace fuse. See Note 1 below.
Reset circuit breaker. See Note 1 below.
Air discharge section is blocked.
Temperature setting is not high or low enough.
Note: Setpoint limits might not allow unit to
heat or cool the room to the temperature
desired. Check section on DIP switch settings.
Air filters are dirty.
Room is excessively hot or cold when unit starts.
Vent door left open.
Unit may be in a protection mode.
Wall sleeve is not installed properly.
Low outdoor temperature.
Dirty filters.
blocking unit’s airflow.
Reset to a lower or higher temperature setting.
Remove and clean filters.
Allow sufficient amount of time for unit to heat or cool the room.
Start heating or cooling before outdoor temperature, cooking heat,
or people make room uncomfortable.
Close vent door.
Check DIP switch settings for desired comfort.
Wait approximately 3 minutes for compressor to start.
and humid weather is normal. See Note 2 below.
If a drain kit has been installed and is connected to a drain system,
condensation. Check that installation is levelled and make any
may form on the indoor coil when un it is in Cooling mode. Switch
unit to FAN operation until ice or frost melts.
Power may have cycled, so compressor is in a
restart protection.
power has been restarted, a random compressor restart will occur.
After a power outage, the compressor will restart after
approximately 3 minutes.
Compressor Protection: To prevent short cycling of compressor,
there is a random startup delay of 3 minutes and a minimum
NOTES
1. If circuit breaker is tripped or fuse is blown more than once, contact a qualified electrician.
2. If unit is installed where condensation drainage could drip in an undesirable location, an accessory
drain kit should be installed and connected to drain system.
Page 35
www.mideaaircon.com 33
Characteristics of Temperature Sensor
KΩ
KΩ
KΩ
Temp. °C/°F
Resistance
Temp. °C/°F
Resistance
Temp. °C/°F
Resistance
-10/14 62.2756
-9 /15.8 58.7079
-8 /17.6 56.3694
-7 /19.4 52.2438
-6 /21.2 49.3161
-5 /23 46.5725
-4 /24.8 44
-3 / 26.6 41.5878
-2 / 28.4 39.8239
-1 /30.2 37.1988
0 /32 35.2024
1 /33.8 33.3269
2 /35.6 31.5635
17/62
18/64
19/66
20/68
21/70
22/72
23/73
24/75
25/77
26/79
27/81
28/82
29/84
14.6181
13.918
13.2631
12.6431
12.0561
11.5
10.9731
10.4736
10
9.5507
9.1245
8.7198
8.3357
44/111
45/113
46/115
47/117
48/118
49/120
50/122
51/124
52/126
53/127
54/129
55/131
56/133
4.3874
4.2126
4.0459
3.8867
3.7348
3.5896
3.451
3.3185
3.1918
3.0707
2.959
2.8442
2.7382
3 /37.4 29.9058
4 /39.2 28.3459
5 /41 26.8778
6 /42.8 25.4954
7 /44.6 24.1932
8 /46.4 22.5662
9 /48.2 21.8094
10 /50 20.7184
11 /51.8 19.6891
12 /53.6 18.7177
13 /55.4 17.8005
14 /57.2 16.9341
15 /59 16.1156
30/86
31/88
32/90
33/91
34/93
35/95
36/97
37/99
38/100
39/102
40/104
41/106
42/108
7.9708
7.6241
7.2946
6.9814
6.6835
6.4002
6.1306
5.8736
5.6296
5.3969
5.1752
4.9639
4.7625
57/135
58/136
59/138
60/140
61/142
62/144
63/145
64/147
65/149
66/151
67/153
68/154
69/156
2.6368
2.5397
2.4468
2.3577
2.2725
2.1907
2.1124
2.0373
1.9653
1.8963
1.830
1.7665
1.7055
16 /60.8 15.3418
43/109
4.5705
70/158
1.6469
Page 36
GD Midea Air-Conditioning Equipment
Co.,Ltd RAC Overseas Sales Company
Midea headquarter building,No.6 Midea Avenue
Beijiao, ShunDe, Foshan, GuangDong, P.R.C, 528311
Website: www.mideaaircon.com
Loading...