Sunways STS-3K User manual

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Grid-connected PV Inverter
Single Phase Dual MPPT
STS-3K/3.6K/4.2K/4.6K/5K/6KTL
User Manual
Sunways Technologies Co., Ltd.

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CONTENTS
1. Preface ........................................................................................................................5
1.1 Overview ........................................................................................................5
1.2 Target Groups ................................................................................................5
2. Safety Instructions ................................................................................................5
2.1 Safety Notes ..................................................................................................5
2.2 Statement ......................................................................................................5
2.3 Important Safety Matters .............................................................................6
2.4 Symbols Explanation ....................................................................................7
3. Product Description .............................................................................................9
3.1 Basic Features ...............................................................................................9
3.2 Physical Layout ...........................................................................................10
3.3 Display Interface .........................................................................................12
3.4 Packing List ..................................................................................................13
4. Installation ..............................................................................................................13
4.1 Location .......................................................................................................13
4.2 Mounting .....................................................................................................15
4.3 Electrical Connection .................................................................................17
4.4 Monitoring Device Installation ...................................................................22
4.5 CT/RS485/DRED Connection ......................................................................23
4.6 System Layout of Units without Integrated DC Switch ............................26
5. Start and Stop .......................................................................................................27
5.1 Start the Inverter .........................................................................................27
5.2 Stop the Inverter .........................................................................................27
6. General Operation ...............................................................................................28
6.1 Display Operation .......................................................................................28
6.2 Auto-Test ......................................................................................................29
6.3 AC Output Boost for STS-5KTL Inverter .....................................................30
6.4 Power Quality Response Modes ................................................................30
6.5 Country Code (Safety Code) Setting ..........................................................30
6.6 Online Monitoring APP ...............................................................................30
7. Troubleshooting...................................................................................................31
7.1 Error Message ..............................................................................................31
7.2 Maintenance ................................................................................................32
8. Technical Parameters ........................................................................................33

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1. Preface
1.1 Overview
This manual is an integral part of Sunways STS 3-6kW series single-phase inverters (hereinafter
referred to as the inverter). It mainly introduces the assembly, installation, electrical
connection, maintenance and troubleshooting of the products. Before installing and using the
inverter, please read this manual carefully, understand the safety information and be familiar
with the functions and characteristics of the inverter.
1.2 Target Groups
This manual is applicable to the electrical installers with professional qualifications and
end-users. If there are any problems in the installation process, please call Sunways
service telephone at [phone] or email Sunways at [e-mail] for
consultation.
2. Safety Instructions
2.1 Safety Notes
2.1.1 Before installation, please read this manual carefully and follow the instructions in this
manual strictly.
2.1.2 Installers need to undergo professional training or obtain electrical related professional
quali󽗉cation certi󽗉cates.
2.1.3 When installing, do not open the front cover of the inverter. Apart from performing
work at the wiring terminal (as instructed in this manual), touching or changing components
without authorization may cause injury to people, damage to inverters and annulment of the
warranty.
2.1.4 All electrical installations must conform to local electrical safety standards.
2.1.5 If the inverter needs maintenance, please contact the local designated personnel for
system installation and maintenance.
2.1.6 To use this grid-connected inverter for power generation needs the permission of the
local power supply authority.
2.1.7 The temperature of some parts of the inverter may exceed 60° C during operation. To
avoid being burnt do not touch the inverter during operation. Let it cool before touching it.
2.1.8 When exposed to sunlight, the PV array generates dangerous high DC voltage. Please
operate according to our instructions, or it will result in danger to life.
2.2 Statement
Sunways Technologies Co., Ltd. has the right not to undertake quality assurance in any of the
following circumstances:
Attention
The products, services or features purchased are subject to the commercial contracts
and terms of Sunways technologies Co., Ltd. All or part of the products, services or
features described in this document may not be within purchased. Unless otherwise
agreed in the contract, the Company shall not make any express or implied declaration
or guarantee of the contents of this document.
Due to product version upgrades or other reasons, the contents of this document will
be updated periodically. Unless otherwise agreed, this document serves only as a
guide to use, and all statements, information and recommendations in this document
do not constitute any express or implied guarantee.
Manufacturer: Sunways Technologies Co., Ltd.
Address: No. 1, Second Road, Green Industrial Zone, Chongshou Town,
Cixi City, ZheJiang Province, PEOPLE’S REPUBLIC OF CHINA
Website: www.sunways-tech.com
Service Mail: [e-mail]
Hotline: [phone]

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2.2.1 Damages caused by improper transportation.
2.2.2 Damages caused by incorrect storage, installation or use.
2.2.3 Damages caused by installation and use of equipment by non-professionals or untrained
personnel.
2.2.4 Damages caused by failure to comply with the instructions and safety warnings in this
document.
2.2.5 Damages of running in an environment that does not meet the requirements stated in
this document.
2.2.6 Damages caused by operation beyond the parameters speci󽗉ed in applicable technical
speci󽗉cations.
2.2.7 Damages caused by unauthorized disassembly, alteration of products or modi󽗉cation of
software codes.
2.2.8 Damages caused by abnormal natural environment (force majeure, such as lightning,
earthquake, 󽗉re, storm, etc.).
2.2.9 Any damages caused by the process of installation and operation which don’t follow the
local standards and regulations.
2.2.10 Products beyond the warranty period.
2.3 Important Safety Matters
Table below shows the symbols that may appear in this document and their de󽗉nition:
2.4 Symbols Explanation
This chapter mainly elaborates the symbols displayed on the inverter, nameplate and packing
box.
2.4.1 Symbols on the Inverter
Danger
Warning
Caution
Dangerous situation, if not avoided, it could result in death or
serious personal injury.
DescriptionSymbol
Potentially dangerous situation, if not avoided, may result in
death or serious personal injury.
Potentially dangerous situation, if not avoided, may result in
moderate or minor personal injury.
Attention The safety warning information about equipment or environment,
to prevent equipment damage, data loss, equipment performance
degradation or other unpredictable results.
Note Symbol highlights important information, best practices and tips,
etc.
2.4.2 Symbol on the Inverter nameplate
The inverter cannot be disposed of with household waste.
DescriptionSymbol
Please read the instructions carefully before installation.
Do not touch any internal parts of the inverter until 5 min after
being disconnected from the mains and PV input.
CE mark, the inverter complies with the requirements of the
applicable CE guidelines.
Danger. Risk of electric shock!
TUV certi󽗉cation.
SAA certi󽗉cation.
The surface is hot during operation and no touch is allowed.
Electric shock hazard, live parts, risk of electric shock, do not
touch.
Inverter status indicator.
DescriptionSymbol
Inverter running indicator.
Grounding symbol, the inverter casing needs to be properly
grounded.

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Figure 3-1 Applicable grid types
STS Single Phase STS Single Phase
STS Single Phase STS Single Phase
3. Product Description
3.1 Basic Features
3.1.1 Function
The Sunways STS 3~6kW series inverter is a single-phase grid-connected PV inverter which
used to e󽗋ciently convert the DC power generated by the PV string into AC power and feed
it into the grid.
3.1.2 The STS 3~6kW series inverter includes 6 models which are listed below:
STS-3KTL, STS-3.6KTL, STS-4.2KTL, STS-4.6KTL, STS-5KTL, STS-6KTL
3.1.3 Applicable grid type
The applicable grid types for the Sunways STS 3~6kW series are TN-S, TN-C, TN-C-S and TT.
When applied to the TT grid, the voltage of N to PE should be less than 30V. For more details
please see Figure 3-1:
3.1.4 Storage conditions
1) Inverter must be stored in its original packaging.
2) The storage temperature and humidity should be in the range of -30 ° C and + 60 ° C, and
less than 90%, respectively.
3) If a batch of inverters needs to be stored, the height of each pile should be no more
than 6 levels.
2.4.3 Symbol on the Packing box
Handle with care.
DescriptionSymbol
This side up.
Keep dry.
Stacked layers.

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Figure 3-2 Front view
Figure 3-3 Side view
3.2 Physical Layout
3.2.1 Inverter front view:
3.2.2 Inverter side view:
360mm
410mm
Logo
Display
Name
Plate
360mm
120mm
Figure 3-4 Bottom view
Figure 3-5 Inverter back view
3.2.3 Inverter bottom view:
3.2.4 Inverter back view:
Back Rail
Vent Valve
120mm
DC Switch (Optional)
DC Input Terminal
Back Rail
Com1 Port Com2 Port (Optional)
AC Output Terminal

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Export limitation & control version 2pcs; RS485 and DRED version 1pcs (This connector
already pre-installed inside the inverter).
② DRED version only (This connector already pre-installed inside the inverter).
4. Installation
4.1 Location
The Sunways STS 3~6kW series inverter is designed with IP65 protection enclosure for indoor
and outdoor installations. When selecting an inverter installation location, the following
factors should be considered:
1) The wall on which the inverter is mounted must be able to withstand the weight of the
inverter.
2) The inverter needs to be installed in a well-ventilated environment.
3) Do not expose the inverter directly to strong sunlight to prevent excessive temperature
operation. The inverter should be installed in a place with shelter to prevent direct exposure to
sunlight and rain.
4) Install the inverter at eye level for easy inspection of screen data and further maintenance.
5) The ambient temperature of the inverter installation location should be between -30 ° C and
60 ° C.
6) The surface temperature of the inverter may reach up to 75 ° C. To avoid risk of burns, do
not touch the inverter while it’s operating and inverter must be installed out of reaching of
children.
4.1.1 Recommended installation location of the inverter, as shown in Figure 4-1:
sunways
3.3 Display Interface
Figure 3-6 Display interface
Inverter × 1 Wall Bracket × 1 Expansion Bolt × 4 PV Terminal × 2
Figure 3-7 Packing list
3.4 Packing List
The package of the inverter includes the following accessories. Please check whether the
accessories in the packing box are complete when receiving the goods. See Figure 3-7 for the
packing list:
Monitoring
Device × 1(Optional)
AC Terminal × 1 Ground Terminal × 1
Item Indicator Status Description
1Power
Indicator
O󽗈 No input voltage detected or input voltage is too low.
Slow 󽗊ashing Inverter powered on, waiting for the grid connection.
Quick 󽗊ashing Inverter detected grid power and entered self-test status.
On Normal, grid-connected and power generated.
2Alarm
Indicator
On An alarm or fault is detected, speci󽗉c fault information can be
viewed from the display.
O󽗈 The inverter is running normally.
Slow 󽗊ashing The monitoring device is not connected to the router or is not
connected to internet.
Quick 󽗊ashing The monitoring device is connected to the router or connected to
internet but not connected to the server.
3OLED
Display
On Display the inverter operating information.
O󽗈 If the button pressed without any response, the screen is faulty or
not well connected.
4 Button Physical
button
Switch OLED display information and set parameters by short
press and long press.
3Pin Terminal × 1①
②
6Pin Terminal × 1
Inspection
Report
User
Manual
Quick
Guide
User Manual × 1
Quick Guide × 1
Inspection Report × 1
Note ①

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Figure 4-1 Recommended installation location
4.2 Mounting
4.2.1 Wall bracket installation
Dimensions of wall bracket, see Figure 4-4:
Figure 4-4 Dimensions of wall bracket
4.1.2 The requirements for inverter installation spacing are shown in Figure 4-2:
4.1.3 The installation angle of the inverter is recommended as shown in Figure 4-3:
Figure 4-2 Recommended installation spacing
Figure 4-3 Recommended installation angle
Do not put 󽗊ammable and explosive articles around the inverter.
Warning
300mm
300mm
500mm 500mm
500mm 500mm
300mm
10mm
16mm
150mm
220mm
110mm 110mm
104mm
1) Use the wall bracket as the template to mark the position of 4 holes on the wall. See Figure
4-5 for details:
Figure 4-5 Marking hole position using installation bracket

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Figure 4-7 Fixing the wall bracket
Figure 4-8 Mounting the inverter
3) Use an electrical driller with 10mm diameter bit to drill 4 holes in the wall with 80 mm depth.
4) Insert the expansion tubes into the holes and tighten them, then 󽗉x the bracket onto the
wall with expansion screws by using a cross screwdriver, as shown in Figure 4-7:
4.2.2 Mounting the inverter
Lift up the inverter, hang the back rail on the 󽗉xed wall bracket carefully. Screws the inverter to
the Z-shaped plate ( The lock is purchased separately). See Figure 4-8 for details:
Before drilling, make sure to avoid any buried water tube and electric wires
in the wall.
Warning
4.3 Electrical Connection
A high voltage in the conductive part of the inverter may cause an electric
shock. When installing the inverter, make sure that the AC and DC sides of the
inverter are completely de-energized.
Do not ground the positive or negative pole of the PV string, otherwise it will
cause serious damage to the inverter.
Static may cause damage to the electronic components of the inverter. Anti-
static measures should be taken during installation and maintenance.
Do not use other brands or other types of terminals other than the terminals in
the accessory package. Sunways has the right to refuse all damages caused by
the mixed-use of terminals.
Moisture and dust can damage the inverter, ensure the cable gland is securely
tightened during installation. The warranty claim will be invalidated if the
inverter is damaged as a result of a poorly connected cable connector.
Danger
Warning
Attention
Attention
Warning
4.3.1 Inverter PV string connection
4.3.1.1 The following must be considered when making electrical connections to the inverter:
1) Disconnect the AC breaker switch on the grid side.
2) The DC switch of the inverter must be turned to the "OFF" position.
3) For best practice, ensure PV modules of the same model and speci󽗉cations are connected in
each string.
2) Bracket assembly
Prepare the two M5 screws and Z-shaped plate in the accessory bag, then 󽗉x the Z-shaped
plate to the mounting bracket.
Figure 4-6 Bracket assembly

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4) Make sure the maximum output voltage of each PV string does not exceed 600V.
4.3.1.2 DC connector assembly procedure
1) Select the appropriate photovoltaic cable:
2) Peel o󽗈 the DC cable insulation sleeve for 7 mm, as shown in Figure 4-9:
Figure 4-9
Wire Traverse area 2.5-4mm27mm
Cable type Traverse area (mm²)
General photovoltaic cable
Range (mm²) Recommended value (mm²)
2.5-4.0 4.0
Figure 4-10
+
-
Crimping Plier
Open-end Wrench
Figure 4-11
Figure 4-12
3) Disassemble the connector in the accessory bag, as shown in Figure 4-10:
4) Insert the DC cable through the DC connector nut into the metal terminal and press the
terminal with a professional crimping plier (pull back the cable with some power to check if
the terminal is well connected to the cable), as shown in Figure 4-11:
5) Insert the positive and negative cables into the corresponding positive and negative
connectors, pull back the DC cable to ensure that the terminal is tightly attached in the
connector.
6) Use an open-end wrench to screw the nut to the end to ensure that the terminal is well
sealed, as shown in Figure 4-12:
1.Before assembling the DC connector, make sure that the cable polarity is
correct.
2.Use a multimeter to measure the voltage of the DC input string, verify the
polarity of the DC input cable, and ensure that each string voltage is within
600V.
Warning
Figure 4-13
7) Insert the positive and negative connectors into the inverter DC input terminals respectively, a
click sound should be heard if the terminals are well connected, as shown in Figure 4-13:
8) Seal the unused PV terminals with the terminal caps.
4.3.2 Connection of AC output
The Sunways STS 3~6kW series single phase inverter operates with grid voltage and frequency
of 220/230V and 50/60Hz, respectively.
This inverter includes an integrated residual current device (RCD) .
If an external residual current device (RCD) is used, a device of type (A/AC etc) should be used,
with a tripping current of 300mA or higher.