Hoymiles HM-600T User manual

Open Energy for All
Single-phase Microinverter
USER MANUAL
HM-600T
HM-700T
HM-800T
Region: North America V202105 hoymiles.com

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 01
Single-phase Microinverter User Manual
About Microinverter
This system is composed of a group of microinverters that convert direct current (DC) into alternating
current (AC) and feed it into the public grid. The system is designed for the incorporation of one
microinverter per two PV modules. Each microinverter works independently and guarantees the
maximum power generation of each PV module. This setup enables the user to directly control the
production of a single PV module, consequently improving the flexibility and reliability of the system.
About the Manual
This manual contains important instructions for the HM-600T/HM-700T/HM-800T Microinverter and
must be read in its entirety before installing or commissioning the equipment. For safety purposes,
only a qualified technician who has received training or has demonstrated competence may install and
maintain this microinverter under the guidance of this document.
Other Information
Product information is subject to change without notice. This user manual will be frequently updated.
Please refer to Hoymiles official website at www.hoymiles.com for the latest version.

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 02
Single-phase Microinverter User Manual
CONTENTS
1. Important Notes 04
1.1 Product Range 04
1.2 Target User 04
1.3 Symbols Used 04
2. About Safety 05
2.1 Important Safety Instructions 05
2.2 Explanation of Symbols 06
2.3 Radio Interference Statement 06
3. About Product 07
3.1 About 2-in-1 Unit 07
3.2 Highlights 07
3.3 Terminals Introduction 07
3.4 Dimension (mm) 07
4. About Function 08
4.1 Work Mode 08
5. About Installation 09
5.1 Accessories 09
5.2 Installation Precautions 09
5.3 Required Space Distance 10
5.4 Grounding Considerations 10
5.5 Preparation 10
5.6 Pre-installation 11
5.7 Installation Steps 11
6. Troubleshooting 14
6.1 Troubleshooting List 14
6.2 Status LED Indicator 17
6.3 Insulation Resistance Detection 17
6.4 On-site Inspection (for qualified installer only) 18
6.5 Routine Maintenance 18
6.6 Microinverter Replacement 19
7. Decommissioning 20
7.1 Decommissioning 20
7.2 Storage and Transportation 20
7.3 Disposal 20
8. Technical Data 21
8.1 DC Input 21
8.2 AC Output 21
8.3 Efficiency, Safety and Protection 22
8.4 Mechanical Data 22
8.5 Features 22

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 03
Single-phase Microinverter User Manual
Appendix 1: 23
Installation Map 23
Appendix 2: 24
WIRING DIAGRAM – 230 VAC SINGLE-PHASE: 24
WIRING DIAGRAM – 230 VAC / 400 VAC THREE-PHASE: 25
WIRING DIAGRAM – 120 VAC / 240 VAC SPLIT-PHASE: 26
WIRING DIAGRAM – 120 VAC / 208 VAC THREE-PHASE: 27

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 04
Single-phase Microinverter User Manual
1. Important Notes
1.1 Product Range
This manual describes the assembly, installation, commissioning, maintenance and failure search for the
following models of Hoymiles Microinverter:
• HM-600T
• HM-700T
• HM-800T
*Note: “600” means 600 W, “700” means 700 W, “800” means 800 W.
1.2 Target User
For safety purposes, only a qualified technician who has received training or has demonstrated competence
may install and maintain this microinverter under the guidance of this document.
1.3 Symbols Used
The safety symbols in this user manual are shown below.
Symbol Usage
Indicates a hazardous situation that can result in deadly electric shock hazards,
other serious physical injury, or fire hazards.
Indicates directions which must be fully understood and followed in their
entirety to avoid potential safety hazards, including equipment damage or
personal injury.
Indicates that the described operation must not be carried out. The reader
should stop, use with caution and fully understand the operations explained
before proceeding.

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 05
Single-phase Microinverter User Manual
2. About Safety
2.1 Important Safety Instructions
The HM-600T/HM-700T/HM-800T Microinverter is designed and tested according to international safety
requirements. However, certain safety precautions must be taken when installing and operating this
microinverter. The installer must read and follow all instructions, precautions and warnings in this installation
manual.
• All operations including transport, installation, start-up and maintenance must be carried out by
qualified and trained personnel.
• Before installation, check the unit to ensure that it is free of any transport or handling damage,
which could affect insulation integrity or safety clearances. Choose an installation location carefully
and adhere to the specified cooling requirements. Unauthorized removal of necessary protections,
improper use, and incorrect installation and operation may result in serious safety and shock hazards
or equipment damage.
• Before connecting the microinverter to the power distribution grid, contact the local power
distribution grid company to obtain the appropriate approvals. This connection must be made only
by qualified technical personnel. It is the responsibility of the installer to provide external disconnect
switches and Overcurrent Protection Devices (OCPD).
• Only one PV module can be connected to one input of the microinverter. Do not connect batteries or
other power supply sources. The microinverter can be used only if all the technical characteristics are
observed and applied.
• Do not install the equipment in adverse environments, such as environments that are flammable,
explosive, corrosive, extremely hot or cold, or humid. Do not use the equipment when the safety
devices do not work or are disabled.
• Always use personal protective equipment, including gloves and eye protection, while installing.
• Inform the manufacturer of non-standard installation conditions.
• Do not use the equipment if any anomalies are discovered while operating. Avoid temporary repairs.
• All repairs should be carried out by using only qualified spare parts, which must be installed in
accordance with their intended use and by a licensed contractor or authorized Hoymiles service
representative.
• Any liability arising from commercial components are delegated to their respective manufacturers.
• Any time the microinverter has been disconnected from the public network, please be extremely
cautious, as some components can retain charge sufficient to create a shock hazard. Prior to
touching any part of the microinverter, please ensure that surfaces and equipment are under safe
touch temperatures and voltage potentials before proceeding.
• Hoymiles accepts no liability for damage due to incorrect or improper operation.
• Electrical Installation & Maintenance shall be conducted by a licensed electrician and shall comply
with local wiring regulations.

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 06
Single-phase Microinverter User Manual
2.2 Explanation of Symbols
Symbol Usage
Treatment
To comply with European Directive 2002/96/EC on Waste Electrical and Electronic
Equipment and its implementation as national law, electrical equipment that
has reached the end of its life must be separately collected and returned to an
approved recycling facility. Any device no longer required must be returned to an
authorized dealer or approved collection and recycling facility.
Caution
Do not come within 8 inches of the microinverter for any length of time while it is
in operation.
Danger of high voltages
Danger to life due to high voltage in the microinverter.
Beware of hot surface
The microinverter can become hot while operating. Avoid contact with metal
surfaces while operating.
CE mark
The microinverter complies with the requirements of the Low Voltage Directive
for the European Union.
Read manual first
Please read the installation manual first before installation, operation and
maintenance.
2.3 Radio Interference Statement
This microinverter has been tested and found to comply with the limits for CE EMC, which provides
reasonable protection against harmful energy. However, if not installed according to the instructions,
the microinverter may cause harmful interference to radio equipment. There is no guarantee that such
interference will not occur during a particular installation.
To confirm that the radio or television reception is affected by interference from this equipment, turn the
equipment off and on to test it. If this equipment causes harmful interference to the radio or television
equipment, try to correct the interference through one or more of the following measures:
1) Relocate the receiving antenna.
2) Increase the separation between the microinverter and the receiving antenna.
3) Place a shield between the microinverter and the receiving antenna, such as a metal / concrete roof.
4) Contact your dealer or an experienced radio/TV technician for help.

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 07
Single-phase Microinverter User Manual
3. About Product
3.1 About 2-in-1 Unit
“Daisy-Chain 2-in-1 Unit Microinverter” with wide DC input operating voltage range (16 V–60 V) and low
start-up voltage (22 V only).
The Hoymiles 2-in-1 Unit Microinverter HM-600T/HM-700T/HM-800T is a reliable solution for PV systems with
an uneven number of panels, and offers high CEC weighted efficiency – 96.50% (peak efficiency 96.70%) in
2015.
3.2 Highlights
• Maximum output power up to 600 W/700 W/800 W. Adapted to 60-cell & 72-cell PV panels.
• Peak eciency 96.70%. CEC weighted eciency 96.50%.
• Static MPPT eciency 99.80%. Dynamic MPPT eciency 99.76% in overcast weather.
• Power factor (adjustable) 0.8 leading…0.8 lagging.
• External antenna for stronger communication with DTU.
• High reliability: NEMA 6 (IP67) enclosure. 6000 V surge protection.
3.3 Terminals Introduction
Object Description
A AC Connector
B DC Connectors
C Antenna
3.4 Dimension (mm)
Unit: mm

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 08
Single-phase Microinverter User Manual
4. About Function
4.1 Work Mode
Normal: In this mode, the microinverter operates normally and converts DC power into AC power to support
the household loads and feeds into the public grid.
Zero Export Control: In this mode, the microinverter’s generation is limited based on the current household
loads, and there is no extra power fed into the public grid.
Standby: There are several circumstances in which the microinverter will be in Standby mode:
• The current condition contradicts with the microinverter operating requirements.
• No household loads or the export control value has been set as “0” on the DTU in the Zero Export Control
mode.

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 09
Single-phase Microinverter User Manual
5. About Installation
5.1 Accessories
Object Description
A AC Bus Cable, 12/10 AWG Cable
B DC Extension Cable, 1 m
C M8 × 25 Screws
D AC Connector Unlocking Tool
E Bus Connector Unlocking Tool
F AC Sub Cap
G AC Bus End Cap, IP67
*Note: All accessories listed above are not included in the package, and need to be purchased separately. Please
contact our sales representative for pricing information. (M8 screws need to be prepared by installer-self.)
5.2 Installation Precautions
Please install the microinverter and all DC
connections under the PV module to avoid
direct sunlight, rain exposure, snow pile-up,
UV, etc. Allow a minimum of 2 cm of space
around the microinverter enclosure to
ensure ventilation and heat dissipation.
*Note: For some countries, the DTU will
be required to meet local grid regulations
(e.g.G98/99 for UK).

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 10
Single-phase Microinverter User Manual
5.3 Required Space Distance
If the microinverters are installed on
a concrete roof or steel roof, their
communication with the DTU may be
slightly affected. Under such installation
conditions, it is better for the microinverters
to be installed 50 cm above the roof.
Otherwise, more DTUs may be required to
ensure communication quality between the
DTUs and the microinverters.
Ground
50 cm
5.4 Grounding Considerations
This microinverter is a Class I equipment with a basic isolation transformer, and this microinverter must be
earthed. There is an earth wire inside the AC cable, so usually grounding can be done by directly using this
wire. If the utility has any special requirements, grounding can be done by affixing the mounting bracket to
the racking.
5.5 Preparation
Installation of this equipment is carried out based on the system design and the place in which the
equipment is installed.
• Installation must be carried out with the equipment disconnected from the grid (power disconnect switch
on) and with the PV modules shaded or isolated.
• Refer to the Technical Data to ensure that the environmental conditions t the requirements of the
microinverter (degree of protection, temperature, humidity, altitude, etc.)
• To avoid power de-rating due to an increase in the internal temperature of the microinverter, do not
expose it to direct sunlight.
• To avoid overheating, always make sure that the air ow around the microinverter is not blocked.
• Do not install in places where gases or ammable substances may be present.
• Avoid electromagnetic interference that can compromise the correct operation of electronic equipment.
When choosing the installation position, comply with the following conditions:
• Only install on structures specically
conceived for PV modules (supplied by
installation technicians).
• Install the microinverter underneath the
PV modules to make sure that it operates
in a shaded or shadowed environment.
If this condition cannot be met, it may
trigger the microinverter production de-
rating.
Fig.1 Microinverter installation position

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 11
Single-phase Microinverter User Manual
5.6 Pre-installation
A) Plan the cable length to make the bus cable aligned with each PV module.
B) Install the AC bus end cap:
• Use the bus connector unlocking tool to
unlock the port upper cover.
• Loosen the three screws with a
screwdriver. Untighten the cap as circled
below, and remove the extra cable.
• Screw the cap back into the port, and
insert the AC bus end cap.
• Plug the upper cover back to the bus
connector.
5.7 Installation Steps
Step 1. Attach Microinverter on Rail
A) Mark the approximate center of each panel on the frame.
B) Fix the screw on the rail.
C) Hang the microinverter on the screw
(as shown in the picture below) and
tighten the screw. The silver cover side
of the microinverter should be facing the
panel.
*Note: Please install the microinverter at
least 50 cm above the ground/roof for
better communication with the Hoymiles
DTU.
Step 2. Complete AC Connection
A) Attach the AC bus cable to the mounting
rail, and affix the cable with ties.
B) Push the AC connector of the
microinverter into the trunk cable
connector until you hear a clicking
sound.
C) If there is any vacant bus port, please
insert the AC sub cap in the vacant
plug to ensure waterproofing and
dustproofing.

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 12
Single-phase Microinverter User Manual
*Note: Under circumstances that require
removing the inverter AC cable from bus
port, please use the AC connector unlocking
tool and insert the tool into the side of the
AC port.
Step 3. Install AC End Cable
A) Prepare an AC end cable with proper
length and insert one side of the cable
into the cap. Match the L, N and Ground
lines into the appropriate slots. Tighten
the screws, and then reinsert the cap
tightly in the port. Plug the upper cover
back to the bus connector.
Coated with solder
B) Connect the other side of the AC end cable to the distribution box, and wire it to the local grid network.
Step 4. Create an Installation Map
A) Peel the removable serial number label
from each microinverter (the position of
the label is shown below).
B) Affix the serial number label to the
respective location on the installation
map.
N S E W
(circle one)
Panel Group:
Azimuth:
Tilt:
Sheet _ of _
Customer Information: DTU Serial Number:
Step 5. Connect PV Modules
A) Mount the PV modules above the
microinverter.
B) Connect the PV modules’ DC cables to
the DC input side of the microinverter.
Step 6. Energize the System
A) Turn on the AC breaker of the branch circuit.
B) Turn on the main AC breaker of the house. Your system will start to generate power after about two
minutes of waiting time.

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 13
Single-phase Microinverter User Manual
Step 7. Set Up the Monitoring System
Refer to the DTU User Manual or DTU Quick Installation Guide, and Quick Installation Guide for S-Miles Cloud
(Hoymiles Monitoring Platform) Online Registration to install the DTU and set up the monitoring system.
Product information is subject to change without notice. (Download reference manuals at www.hoymiles.
com.)

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 14
Single-phase Microinverter User Manual
6. Troubleshooting
This microinverter can only work with the new Hoymiles DTU (DTU-Pro, DTU-Lite and DTU-W100/DTU-G100)
with the following serial number.
Model Serial Number
DTU-Pro
10F7xxxxxxxx
10F8xxxxxxxx
10FAxxxxxxxx
DTU-G100 10D2xxxxxxxx
DTU-W100 10D3xxxxxxxx
DTU-Lite 10D6xxxxxxxx
6.1 Troubleshooting List
Alarm Code Alarm Name Suggestion
121 Over temperature
protection
1. Check the ventilation and ambient temperature at the microinverter
installation position.
2. If the ventilation is poor or the ambient temperature exceeds the
limit, improve the ventilation and heat dissipation.
3. If both the ventilation and ambient temperature meet the
requirements, contact your dealer or Hoymiles Technical Service
Center.
125 Grid configuration
parameter error
1. Check if the grid configuration parameter is correct and upgrade
again.
2. If the fault still exists, contact your dealer or Hoymiles Technical
Service Center.
126 Software error code 126
1. If the alarm occurs accidentally and the microinverter can still
function normally, no special treatment is required.
2. If the alarm occurs frequently and cannot be restored, contact your
dealer or Hoymiles Technical Service Center.
127 Firmware error
1. Check if the firmware is correct and upgrade again.
2. Check the communication between the DTU and Hoymiles Monitoring
System, as well as the communication between the DTU and the
microinverter. Then try again.
3. If the fault still exists, contact your dealer or Hoymiles Technical
Service Center.
128 Software error code 128
1. If the alarm occurs accidentally and the microinverter can still
function normally, no special treatment is required.
2. If the alarm occurs frequently and cannot be restored, contact your
dealer or Hoymiles Technical Service Center.
129 Software error code 129
1. If the alarm occurs accidentally and the microinverter can still
function normally, no special treatment is required.
2. If the alarm occurs frequently and cannot be restored, contact your
dealer or Hoymiles Technical Service Center.
130 Offline
1. Please check if the microinverter works normally.
2. Check the communication status between the DTU and Hoymiles
Monitoring System, or between the DTU and the microinverter. Try to
make improvements if the communication is poor.
3. If the alarm occurs frequently and cannot be restored, contact your
dealer or Hoymiles Technical Service Center.

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 15
Single-phase Microinverter User Manual
141 Grid overvoltage
1. If the alarm occurs accidentally, the grid voltage may be temporarily
abnormal. The microinverter will automatically recover after grid
voltage returns to normal.
2. If the alarm occurs frequently, check whether the grid voltage is
within the acceptable range. If it is not, contact the local power
operator or change the grid overvoltage protection limit via the
Hoymiles Monitoring System after obtaining the consent of the local
power operator.
142 Grid overvoltage
(10-minute average value)
1. If the alarm occurs accidentally, the grid voltage may be temporarily
abnormal. The microinverter will automatically recover after grid
voltage returns to normal.
2. If the alarm occurs frequently, check whether the grid voltage is
within the acceptable range. If it is not, contact the local power
operator or change the grid overvoltage protection limit via the
Hoymiles Monitoring System after obtaining the consent of the local
power operator.
143 Grid undervoltage
1. If the alarm occurs accidentally, the grid voltage may be temporarily
abnormal. The microinverter will automatically recover after grid
voltage returns to normal.
2. If the alarm occurs frequently, check whether the grid voltage is
within the acceptable range. If it is not, contact the local power
operator or change the grid undervoltage protection limit via the
Hoymiles Monitoring System after obtaining the consent of the local
power operator.
3. If the fault still exists, check the AC switch or AC wiring.
144 Grid overfrequency
1. If the alarm occurs accidentally, the grid frequency may be
temporarily abnormal. The microinverter will automatically recover
after grid frequency returns to normal.
2. If the alarm occurs frequently, check whether the grid frequency
is within the acceptable range. If it is not, contact the local power
operator or change the grid overfrequency protection limit via the
Hoymiles Monitoring System after obtaining the consent of the local
power operator.
145 Grid underfrequency
1. If the alarm occurs accidentally, the grid frequency may be
temporarily abnormal. The microinverter will automatically recover
after grid frequency returns to normal.
2. If the alarm occurs frequently, check whether the grid frequency
is within the acceptable range. If it is not, contact the local power
operator or change the grid underfrequency protection limit via the
Hoymiles Monitoring System after obtaining the consent of the local
power operator.
146 Rapid grid frequency
changes
1. If the alarm occurs accidentally, the grid frequency may be
temporarily abnormal. The microinverter will automatically recover
after grid frequency returns to normal.
2. If the alarm occurs frequently, check whether the grid frequency
change rate is within the acceptable range. If it is not, contact the
local power operator or change the grid frequency change rate limit
via the Hoymiles Monitoring System after obtaining the consent of
the local power operator.
147 Power grid outage Please check whether there is a power grid outage.
148 Grid disconnection Please check whether the AC switch or AC wiring functions normally.
149 Island detected
1. If the alarm occurs accidentally, the grid voltage may be temporarily
abnormal. The microinverter will automatically recover after grid
voltage returns to normal.
2. If the alarms occur frequently on all the microinverters in your
station, contact the local power operator to check whether there is a
grid island.
3. If the alarm still exists, contact your dealer or Hoymiles Technical
Service Center.

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 16
Single-phase Microinverter User Manual
205 Input port overvoltage
1. Please make sure that the PV module open-circuit voltage is less than
or equal to the maximum input voltage.
2. If the PV module open-circuit voltage is not within the normal range,
contact your dealer or Hoymiles Technical Service Center.
207 Input port undervoltage
1. Please make sure that the PV module open-circuit voltage is less than
or equal to the maximum input voltage.
2. If the PV module open-circuit voltage is not within the normal range,
contact your dealer or Hoymiles Technical Service Center.
209 Port no input
1. Please confirm whether this port is connected to the PV module.
1. If the PV module is connected, please check the DC cable connection
between this port and the PV module.
210 Port 2 no input
1. Please confirm whether this port is connected to the PV module.
2. If the PV module is connected, please check the DC cable connection
between this port and the PV module.
301 Hardware error code 301
1. If the alarm occurs accidentally and the microinverter can still
function normally, no special treatment is required.
2. If the alarm occurs frequently and cannot be restored, contact your
dealer or Hoymiles Technical Service Center.
302 Hardware error code 302
1. If the alarm occurs accidentally and the microinverter can still
function normally, no special treatment is required.
2. If the alarm occurs frequently and cannot be restored, contact your
dealer or Hoymiles Technical Service Center.
303 Hardware error code 303
1. If the alarm occurs accidentally and the microinverter can still
function normally, no special treatment is required.
2. If the alarm occurs frequently and cannot be restored, contact your
dealer or Hoymiles Technical Service Center.
304 Hardware error code 304
1. If the alarm occurs accidentally and the microinverter can still
function normally, no special treatment is required.
2. If the alarm occurs frequently and cannot be restored, contact your
dealer or Hoymiles Technical Service Center.
305 Hardware error code 305
1. If the alarm occurs accidentally and the microinverter can still
function normally, no special treatment is required.
2. If the alarm occurs frequently and cannot be restored, contact your
dealer or Hoymiles Technical Service Center.
306 Hardware error code 306
1. If the alarm occurs accidentally and the microinverter can still
function normally, no special treatment is required.
2. If the alarm occurs frequently and cannot be restored, contact your
dealer or Hoymiles Technical Service Center.
307 Hardware error code 307
1. If the alarm occurs accidentally and the microinverter can still
function normally, no special treatment is required.
2. If the alarm occurs frequently and cannot be restored, contact your
dealer or Hoymiles Technical Service Center.
308 Hardware error code 308
1. If the alarm occurs accidentally and the microinverter can still
function normally, no special treatment is required.
2. If the alarm occurs frequently and cannot be restored, contact your
dealer or Hoymiles Technical Service Center.

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Single-phase Microinverter User Manual
6.2 Status LED Indicator
The LED flashes five times at startup. All green flashes (1s gap) indicate normal startup.
Status LED
(1) Startup Process
• Five green flashes (0.3s gap): Startup success
• Five red flashes (0.3s gap): Startup failure
(2) Running Process
• Fast green flashing (1s gap): Producing power.
• Slow green flashing (2s gap): Producing power, but one input is abnormal.
• Slow green flashing (4s gap): Producing power, but there is no communication with DTU.
• Red flashing (1s gap): Not producing power, AC grid fault (voltage or frequency out of range).
• Red flashing (0.5s gap): Non-grid abnormality fault.
(3) Other Status
• Alternating red and green flashing: Firmware is corrupted.
*Note: All faults are reported to the DTU, refer to the local DTU app or S-Miles Cloud (Hoymiles Monitoring
Platform) for more information.
6.3 Insulation Resistance Detection
There is a resistance sensor in the microinverter to measure the resistance between the outputs of PV
module and the ground. If there is a problem with PV module insulation, DC wiring or connectors of the
module and so on, the resistance between the outputs of the module and the ground may decrease. If this
resistance drops below a preset threshold, the microinverter will stop producing power and report this
ground fault. This fault will persist until it is cleared on the S-Miles Cloud (Hoymiles Monitoring Platform). This
fault will persist until the microinverter is rebooted.
Please note that this fault cannot be cleared if the cause of the failure is still present. If the fault persists,
contact your installer or Hoymiles for possible replacement.

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 18
Single-phase Microinverter User Manual
6.4 On-site Inspection (for qualified installer only)
To troubleshoot an inoperable microinverter, follow the steps mentioned below.
1Verify that the utility voltage and frequency are within ranges shown in the Technical Data
appendix of this microinverter.
2
Check the connection to the utility grid. Verify that the utility power is present at the
microinverter in question by removing AC, then DC power. Never disconnect the DC wires
while the microinverter is producing power. Re-connect the DC module connectors and
watch for five short LED flashes.
3Check the AC branch circuit interconnection between all the microinverters. Verify that each
microinverter is energized by the utility grid as described in the previous step.
4 Make sure that any AC breakers are functioning properly and are closed.
5 Check the DC connections between the microinverter and the PV module.
6Verify that the PV module DC voltage is within the allowable range shown in the Technical
Data appendix of this manual.
7 If the problem persists, please call Hoymiles customer support.
Do not try to repair the microinverter. If troubleshooting fails, please return it to the factory
for replacement.
6.5 Routine Maintenance
1. Only authorized personnel are allowed to carry out the maintenance operations, and such personnel are
responsible for reporting any anomalies.
2. Always use the personal protective equipment provided by the employer when carrying out maintenance.
3. During normal operation, check that the environmental and logistical conditions are correct. Make sure
that these conditions have not changed over time and that the equipment is not exposed to adverse
weather conditions and has not been covered with foreign bodies.
4. DO NOT use the equipment if any problems are found, and restore the proper conditions after resolving
the problems.
5. Conduct an annual inspection of the various components, and clean the equipment with a vacuum cleaner
or special brushes.
Do not attempt to dismantle the microinverter or make any internal repairs! In order to preserve the
integrity of safety and insulation, the microinverters are not designed to allow internal repairs!
The AC output wiring harness (AC drop cable on the microinverter) cannot be replaced. If the cord is
damaged, the equipment should be scrapped.
Maintenance operations must be carried out with the equipment disconnected from the grid (grid
power switch on) and the PV modules obscured or isolated, unless otherwise indicated.
For cleaning, do not use rags made of filamentary materials or corrosive products that may corrode
parts of the equipment or generate electrostatic charges.
Avoid temporary repairs. All repairs should be carried out by using only genuine spare parts.
If all microinverters connect to the DTU-Pro, the DTU can limit the output power imbalance of all
microinverters between phases to below 3.68 kW if required. Please refer to the “Hoymiles Technical
Note Limit Phase Balance” for more details.

© 2021 Hoymiles Power Electronics Inc. All rights reserved. 19
Single-phase Microinverter User Manual
Each branch should provide a circuit breaker, but a central protection unit is not required.
6.6 Microinverter Replacement
a. How to remove the microinverter.
• De-energize the AC branch circuit breaker.
• Remove the PV panel from the racking and cover the panel.
• Use a meter to measure and make sure that there is no current flowing in the DC wires between the
panel and the microinverter.
• Use the DC disconnect tool to remove the DC connectors.
• Use the AC disconnect tool to remove the AC connectors.
• Unscrew the fixing screw on the top of the microinverter and remove the microinverter from the PV
racking.
b. How to replace the microinverter:
• Please record down the new microinverter’s SN.
• Please make sure that the AC branch circuit breaker is off, and follow the microinverter installation
steps to install the replacement unit.
• Go to the Monitoring Platform (if the customer already registered this station online) and access the
“Devices” page to find the device that you just replaced. Click the “Device Maintenance” button to
jump to the new page and select “Replace Device”. Enter the new microinverter’s SN and click the “OK”
button to complete the replacement.