innovair Inverter FLEX24 SEV2040H2R18 User manual

FLEX24
HEAT PUMP
SPLIT SYSTEM
SERVICE MANUAL
• The information contained in the manual is intended for use by a qualified service technician
familiar with safety procedures and equipped with the proper tools and test instruments
• Installation or repairs made by unqualified persons can result in hazards to you and others.
• Failure to carefully read and follow all instructions in this manual can result in equipment
malfunction, property damage, personal injury and/or death.
• This service is only for service engineer to use.
SEV2040H2R18
SEV3060H2R18
DEV24H2R18
DEV36H2R18
DEV48H2R18
DEV60H2R18

Foreword
Thank you for choosing Innovair FLEX24 air conditioners. In order to correctly install and use our units, and
for the satisfactory operation effect, please read this manual carefully.
This manual specifies safe operation requirements from perspectives of product introduction, control,
troubleshooting and maintenance, as well as basic principles and implementation methods. Professional
operators must abide by relevant national (local) safety requirements and technical specifications set forth in
this manual during operations; otherwise, the air conditioning system may fail or be damaged, and personnel
safety accident may also occur.
Safety Notice
Before using the air conditioner, please first read the instruction manual.
Before installing the air conditioner, please first read the instruction manual.
Before repairing the air conditioner, please first read the technical service manual.
SERVICE MANUAL Innovair Elite Mini Split

CONTENTS
1 Product Introduction ......................................................................................................3
1.1 Lists of Units ..........................................................................................................................3
1.2 Electrical Parameters .............................................................................................................5
2 Control.............................................................................................................................6
2.1 Operation Mode .....................................................................................................................6
2.2 Control Mode .........................................................................................................................8
2.3 Functions .............................................................................................................................10
3 Troubleshooting............................................................................................................14
3.1 Wiring Diagrams ..................................................................................................................14
3.2 PCB Layout..........................................................................................................................17
3.3 Error Code ...........................................................................................................................25
3.4 Troubleshooting ...................................................................................................................26
3.5 Failures Not Caused by Errors .............................................................................................53
4 Maintenance ..................................................................................................................55
4.1 System Diagram ..................................................................................................................55
4.2 Connection Pipe Vacuum Pumping ......................................................................................55
4.3 Refrigerant Charging............................................................................................................57
4.4 Maintenance of Major Components......................................................................................59
4.5 Removal of Major Components............................................................................................69
4.6 Explosive View and Lists of Parts.......................................................................................104
Appendices .................................................................................................................... 110
1 Resistance/Temperature Lists of Temperature Sensors ......................................... 110
1.1 Voltage List of 15 KΩTemperature Sensors....................................................................... 110
1.2 Voltage List of 20 KΩPipeline Temperature Sensors ......................................................... 112
1.3 Voltage List of 50 KΩDischarge Temperature Sensors ...................................................... 114
2 Temperature/Pressure List of Refrigerant ................................................................ 117
3 Operation Tools .......................................................................................................... 117
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1
Safety Notice on Maintenance
PROHIBITED：
(1) Do not pierce or burn.
(2) Please note that refrigerant may be odorless.
(3) The appliance shall be stored in a room without continuously operating ignition sources (For example:
open flames, an operating gas appliance or an operating electric heater).
(4) Indoor unit adopts special joints that can’t be detached. The installation method is the same with the
common joints. However, because the joint can’t be detached, if it is badly connected and causes leakage,
it needs to be cut and replaced by a new one through welding.
(5) Using unsuitable parts or tools may lead to electric shock or fire hazard.
(6) If refrigerant leaks during maintenance, please ventilate the room immediately. Heavy leakage may lead to
breathing difficulty, severe injury or death.
(7) Disconnect power before disassembling the appliance for maintenance.
(8) The appliance should be maintained and cared by authorized technical personnel with necessary
qualifications.
WARNING:
(1) If the working place is more than 2m's high, please wear a safety helmet, gloves and a safety belt.
(2) Never mix any other substances except the specified refrigerant into the refrigerant circuit.
(3) When re-locating the appliance, check whether the new location is strong enough to withstand the weight
of the appliance.
(4) If there is refrigerant leak, please fix the leak before charging in the refrigerant. After refrigerant is charged,
check for refrigerant leaks. If you cannot spot the leak, stop the maintenance work. Please evacuate the
system and close the service valve to prevent refrigerant leaking into the room.
(5) Prepare suitable tools and protectors.
(6) If you need to carry out maintenance or check the electric circuit without cutting off the power, please be
careful not to touch the electrical parts.
NOTICE:
(1) If the appliance is maintained at a humid place, it should be grounded to avoid electric shock.
(2) Never repair the unit with wet hands. Operating the unit with wet hands may lead to electric shock.
(3) If the unit is not correctly grounded, please check and fix it.
(4) Before cleaning the unit, please disconnect power to prevent the inner fan from starting up and running at

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high speed; Otherwise personal injury may occur.
(5) Measure the insulation resistance after maintenance. The resistance must be 1M or higher. Bad insulation
may lead to electric shock.
(6) Welding and cutting work must be done in a well-ventilated place.
(7) Gas appliances, heaters and other fire sources should be kept away from the installation and maintenance
site.
(8) Maintenance should be done according to suggestions of the manufacturer.
(9) Maintenance should be done only after the refrigerant is completely reclaimed from the unit.
OBSERVED：
(1) After the maintenance work is done, check the drainage of indoor unit.
(2) Do not tilt the unit, otherwise, water may spill out from the unit and make the floor and furniture wet.
(3) Disassembly of the unit, handling of the refrigerant, oil and accessories should all be done according to
applicable local rules and regulations.
Safety Notice on Operation
PROHIBITED:
(1) Never try to modify the unit, otherwise, it may cause electric shock, overheat or fire hazard.
(2) If the power cord or conducting wires are scratched, please replace them.
(3) Never use connected or extended power cord or share the power socket with other appliances.
(4) Prepare a specialized power circuit for the appliance.
WARNING:
(1) If the power plug is dirty, please clean it before inserting it to the power socket. If the power plug is loose,
please tighten it up.
(2) Do not damage the power cord. A damaged or refitted power cord may lead to electric shock or fire hazard.
(3) Check frequently whether the appliance is in good condition.
NOTICE:
(1) After changing the batteries of remote control, please discard them to avoid being swallowed by children.
(2) When the unit is working, do not remove the fan cover.
(3) Do not use organic solvents to wipe the controller operating panel.
(4) Before cleaning the unit, cut off the power supply.

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3
1 Product Introduction
1.1 Lists of Units
1.1.1 List of Outdoor Units
SEV2040H2R18 208/230V-1Ph-60Hz
SEV3060H2R18 208/230V-1Ph-60Hz
Power Supply
Model Appearance
V/Ph/Hz

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1.1.2 List of Indoor Units
Airhandler DEV24H2R18 24000/24000 208/230V-1Ph-60Hz
Airhandler DEV36H2R18 36000/36000 208/230V-1Ph-60Hz
Airhandler DEV48H2R18 48000/48000 208/230V-1Ph-60Hz
Airhandler DEV60H2R18 54000/54000 208/230V-1Ph-60Hz
NOTE: 1 Ton =12000Btu/h = 3.517kW
Power Supply
Cooling/Heating
Model Appearance
Capacity (Btu/h) V/Ph/Hz

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1.2 Electrical Parameters
SEV2040H2R18 208/230V-1Ph-60Hz 35
SEV3060H2R18 208/230V-1Ph-60Hz 45
Power Supply Fuse Capacity Circuit Breaker Capacity
Model V/Ph/Hz A A
DEV24H2R18 208/230V-1Ph-60Hz 5 15
DEV36H2R18 208/230V-1Ph-60Hz 3.15 15
DEV48H2R18 208/230V-1Ph-60Hz 3.15 15
DEV60H2R18 208/230V-1Ph-60Hz 3.15 15
Power supply Circuit breaker capacity
Model V/Ph/Hz A

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2 Control
2.1 Operation Mode
2.1.1 Cooling Mode

2.1.2 Heating Mode
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2.2 Control Mode
2.2.1 Based Control
2.2.1.1 Compressor Control
When cooling or heating mode is turned on, indoor fan will run for a while before the compressor starts.
Under different modes, the compressor can only be stopped after running for some time (special cases excluded).
This is to protect the compressor from frequent start or stop. Once the compressor is stopped, it must not be
restarted right away. Please wait for a few minutes.
2.2.1.2 EXV Control
When the unit is first started, the electronic expansion valve will reset control. During the process, the
expansion valve will produce rattling sound. When cooling or heating mode is turned on, the valve will be open at
a certain step before the compressor starts.
2.2.1.3 Outdoor Fan Control
This series air conditioner has two types of outdoor units: one with a single fan and the other with double
fans. The outdoor fan can run at the highest level 10 and the lowest level 1. By controlling the speed of outdoor
fan, the unit can achieve cooling at low temperature and heating at high temperature. In fan mode, outdoor fan
will not work.
2.2.1.4 4-way Valve Control
After heating mode is turned on for a while, 4-way valve will be energized to change the direction of
refrigerant flow so that the system can run in heating and the indoor unit will not blow cold air. Under other modes,
the valve will not be energized.
To avoid the 4-way valve from incorrectly changing directions, when the unit stops in heating, due to a
temperature point or other protection reasons, the 4-way valve will continue to function temporarily and lose
power after a while.
There must be adequate differential pressure for the 4-way valve to change directions.
2.2.2 Special Control
2.2.2.1 Defrosting Control
ODU defrosting control in heating: Defrosting will start when the temperature sensed by outdoor tube
temperature sensor reaches a preset value. During defrosting, the 4-way valve will switch to the cooling condition
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and outdoor and indoor fan will both stop. When the temperature sensed by outdoor tube temperature sensor
reaches the preset value of defrosting stop, system will quit defrosting. The 4-way valve will switch back to the
heating condition, compressor and outdoor unit fan restart.
2.2.2.2 Oil Return Control
If the unit is running at low frequency for a long time, system will enable oil return control. This is to lead oil in
the pipeline back to the compressor so that the compressor will not be lack of oil. Generally, the oil return takes
about 5min. The compressor running frequency will be raised to the preset oil return frequency.
2.2.3 Protection Control
2.2.3.1 High Pressure Protection Control
System will enable high pressure protection control if the high pressure switch is detected open for
continuously a little time. Under high pressure protection, system will be shut down and display error code E1.
When high pressure protection occurs for the first time, system will restore operation if the high pressure
switch is detected to be reclosed for continuously a little time. When high pressure protection occurs for the
second time in a certain time period, system will not restore operation. You need to manually turn off the unit and
clear the error before restarting up the unit. (If high pressure protection occurs frequently, please send for
professional personnel torepair.)
2.2.3.2 Low Pressure Protection Control
System will enable low pressure protection control if the low pressure switch is detected open for
continuously a little time. Under low pressure protection, system will be shut down and display error code E3.
When low pressure protection occurs, system will restore operation if the low pressure switch is detected to be
reclosed within a few minutes after shutdown. If low pressure protection occurs for several times in a period of
time, system will not restore operation automatically. You need to manually turn off the unit before restarting up
the unit.
2.2.3.3 High Temperature Prevention Control
Under heating mode, system will enable high temperature prevention control if the temperature sensed by
indoor tube temperature sensor reaches a certain value. When high temperature prevention control is enabled,
outdoor fan will slow down.
2.2.3.4 Discharge High Temperature Protection Control
System will enable discharge temperature protection control if the discharge high temperature sensor is
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detected open for continuously a little time. Under discharge high temperature protection, system will be shut
down and display error code E4. When discharge high temperature protection occurs, system will restore
operation if the discharge high temperature sensor is detected to be reclosed within a few minutes after shutdown.
If discharge high temperature protection occurs for several times in a period of time, system will not restore
operation automatically. You need to manually turn off the unit before restarting up the unit.
2.3 Functions
2.3.1 Set Capacity Dip Switch
Set the capacity of the outdoor unit through the four dip switches of the outdoor unit main control board.
Specific dip switch definition, the first dip switch distinguishes the capacity.
Dip Switches
2.3.2 Set Defrost Mode
The second dip switch is selecting the defrost mode.
The second dip switch is used to change the defrost setting, factory default setting is standard defrost. Under
extremely low environment temperature, if the standard defrost cannot have the condenser defrosted completely,
please set the second dip switch to be strong defrost. Under strong defrost, the defrosting time will be longer,
which enable the condenser to be defrosted completely.
Standard Defrost
(Default)
Strong Defrost
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Capacity 24K 36K 48K 60K
Defrost mode Outdoor unit dip switches

2.3.3 Set Operating Mode
The third dip switch and the fourth dip switch are selecting the operating mode. Standard mode is the
conventional mode.
By setting the strong mode dip switches of the condensing unit, the air conditioner can quickly increase the
capacity output and ensure reliable operation in a short time, so as to meet the user's demand for the indoor
temperature to quickly reach the set temperature.
Energy saving mode is achieved by setting the condensing unit operating mode to operate the air
conditioner within a small load range.
Operating mode Outdoor unit dip switches
Standard mode (Default)
Strong mode
Energy saving mode
2.3.4 Set Indoor Fan Speed
Set the indoor fan speed through the eight dip switches of the indoor main control board. The higher level,
the higher speed of the indoor unit fan.
Capacity 24K indoor unit dip switches 36K indoor unit dip switches
Level 1
(Default)
Level 2
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Level 3
2.3.5 Forced Defrost Control
Press and hold "SW1" for about 5s to enter the first level menu of the debugging mode, the outdoor unit
mainboard LED displayer flashes. Under the first level menu, short press "SW1" to switch various functions. After
switching to "06", short press "SW2" or "SW3" to enter the forced defrosting mode, "ON" means open, "OF"
means close, and then short press "SW1" to save. During debugging, if no operation is performed within 10s, the
debugging mode interface will be exited.
2.3.6 Refrigerant Recovery Control
Press and hold "SW1" for about 5s to enter the first level menu of the debugging mode, the outdoor unit
mainboard LED displayer flashes. Under the first level menu, short press "SW1" to switch various functions. After
switching to "08", short press "SW2" or "SW3" to enter the refrigerant recovery control mode, "ON" means open,
"OF" means close. And then short press "SW1" to save. During debugging, if no operation is performed within
10s, the debugging mode interface will be exited.
2.3.7 Forced Operation Control
Press and hold "SW1" for about 5s to enter the first level menu of the debugging mode, the outdoor unit
mainboard LED displayer flashes. Under the first level menu, short press "SW1" to switch various functions. After
Capacity 48K indoor unit dip switches 60K indoor unit dip switches
Level 1
(Default)
Level 2
Level 3
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switching to "09", short press "SW2" or "SW3" to enter the forced operation control mode, "01" denotes that turn
on the forced operation cooling mode; "02" denotes that turn on the forced operation cooling mode; "OF"
indicates that shut down the forced cooling /heating mode. And then short press "SW1" to save. During
debugging, if no operation is performed within 10s, the debugging mode interface will be exited.
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3 Troubleshooting
3.1 Wiring Diagrams
The following electric diagram is for reference only. Please refer to diagram sticked on the unit as the latest
version.
3.1.1 WiringDiagrams of ODUS
Model: SEV2040H2R18
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Model: SEV3060H2R18
3.1.2 Wiring Diagrams of IDUs
Model: DEV24H2R18, DEV36H2R18
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Model: DEV48H2R18, DEV60H2R18
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3.2 PCB Layout
3.2.1 Interface
Indoor unit:
Model: DEV24H2R18, DEV36H2R18, DEV48H2R18, DEV60H2R18
Mainboard
No. Printing Interface No. Printing Interface
1 AC-N
（
X2
）
Neutral wire input 8 X9(G_SCAN) Indoor motor check
2 AC-L （X1）Live wire input 9 X14(OFAN-H-OUT) AC motor high speed
output
3 CN3
Wired control
communication
interface
10 X11(OFAN-H-IN) AC motor high speed input
4 CN1 DC motor output 11 X8(OFAN-L-IN) AC motor low speed input
5 X7 Transformer Neutral wire
input 12 X6(OFAN-L-OUT) AC motor low speed output
6 X13 Transformer Live wire
input 13 X3(C) Transformer Neutral wire
output
7 X10(O_SCAN) 4-Way check 14 X4(R) Transformer Live wire
output
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