Homeowner Frequently Asked Questions

The FAQ provided below is intended as a support resource for homeowners and non-professional DIY installers. If you are a professional installer, please click here to visit the Installer FAQ.

You can also review our DIY installer policy here.


Do I need a professional installer?

Yes. For reasons of homeowner safety and proper system installation, APsystems requires installation by a professional solar installer. These installers are aware of safety requirements, codes and standards, are licensed and bonded to work on electrical systems and roofs, and are trained to use APsystems equipment. Even if you’re savvy with electrical equipment, electrical code issues, if improperly addressed, could result in serious damage to person or property.
APsystems’ policy requires professional installation in order to set up an EMA monitoring account, and to service or troubleshoot the system. See our policy on DIY installations here.

I think there’s a problem with my solar array. What do I do?

Contact your original solar installer. They can help resolve your issue, whether it is a log-in problem, a production issue or hardware. They are licensed and certified for troubleshooting and, if needed, replacing our product. If they need additional support they will contact us. If your solar installer is no longer available, we can refer you to an experienced installer in your area.

What if I want to change my system settings?

Your system settings are defined as per grid and code requirements and should only be changed in rare circumstances. For example, if your system is located in an area where the grid performance is unstable, the parameters can be adjusted to tolerate the grid’s instability. If you experience such issues with the grid in your area, please contact your solar installer. They have the ability to adjust the necessary parameters of your system.

Does APsystems sell direct to homeowners?

No. APsystems sells exclusively through a network of authorized distributors who sell to professional solar installers.

I self-installed my system and now I’m experiencing problems. What do I do?

You will need to contact a professional solar installer to troubleshoot your system. They will work with us to determine the cause and fix the issue and, if needed, replace any defective units. Often times, troubleshooting requires electrical work or work on the roof. APsystems requires homeowners to work with a professional solar installer to resolve system issues for reasons of safety and liability.

How do I view my systems energy production online or on my smart phone?

Upon initial set up of your solar array, your installer will create your account in the EMA and provide you with log-in credentials to view your energy production. Simply download the EMA APP available in the App Store or access the EMA portal online at apsystemsema.com and enter the user name and password provided by your installer.

How do I monitor my system or how do I know what is being produced?

For every PV system powered by APsystems microinverters, monitoring is available for end-user when the PV system is hooked-up with an ECU (Energy Communication Unit) connected to the internet at home. Using the EMA APP or the EMA web portal, the end-user can monitor the performance of their system on a daily /monthly / yearly basis even when they are not at home.

I did not receive my log-in credentials from my installer to view my energy production online and on my smart phone. What do I do?

You will need to contact your solar installer to have your account set up. They have the ability to create and update system owner accounts for their customers. If they are not responsive or no longer in business, contact APsystems technical support in your region.

I am a DIY installer and I need an EMA account. What do I do?

APsystems does not support DIY self-installers, only professional solar installers. They are familiar with the current codes and standards needed to keep you and your families safe with solar. If you have not yet completed your installation, we encourage you to hire a professional installer. If you have already installed your system, please see this guide for DIY account creation


Your product manuals and online videos talk about the microinverter ‘UID’, what is a UID?

The UID (Unique IDentifier) or serial number is a unique 12 digit number assigned to all microinverters.

Where do I find the UID (serial number) of my Microinverter?

The UID or serial number is located on the front of the device and is a 12 digit number starting with a “4” (YC500 or YC600), a ‘5’ (YC1000) or a ‘8’ (QS1)

What type of PV modules (panels) should I pair with APsystems inverters?

APsystems micros work well with most of 60 or 72 cells PV modules. APsystems is agnostic to the brand of PV panel you choose. YC600 and QS1 inverters output 300W per channel. This does not mean pairing them with a 300W PV module. You will always want to oversize the PV module since the rated STC listing is under optimal conditions and you often won’t have that due to weather, shading, clouds, leaves, dust, etc., not to mention the wear and tear over 25 years that will degrade your panel quality. Most professional installers use a sizing ratio of 1.2 or 1.25 to determine the ideal panel sizing for your inverter. That would mean a PV module of 360W to 375W for pairing with the YC600 and QS1. Higher capacity PV modules will not damage or negatively affect the inverter. You will simply have increased clipping. Be sure to also check the PTC listing of the PV module for a more accurate expectation of power output.

My inspector is asking about my product/solar equipment. How can I answer his questions?

Contact your installer who can provide all the specs and information on the products used in your solar array. They can and typically do work with the inspectors on your behalf.

What is the maximum AC W output of your inverters?

To view specifications, visit our library.

Are APsystems’ microinverters ok for a coastal environment?

Absolutely, APsystems has done HALT testing which includes; damp heat, humidity freeze, salt mist and UV.

Do the APsystems microinverters have built-in reactive power control (power factor control) to avoid penalties with my utility company?

The QS1 and YC600 are compliant with local regulations regarding RPC, including California Rule 21, EN50549, and VDE AR-N 4105.

Does APsystems recommed surge protection for the PV array?

Yes, APsystems strongly recommends to install a whole-house surge protection device at the dedicated meter box. Please check with you local regulations and your professional installer.

I have an off-grid application, can I use your microinverters?

No, APsystems does not offer an off-grid product at this time. All APsystems products comply with IEEE-1547 anti-islanding standard.


I’m having trouble logging into my system. What should I do?

First visit apsystemsema.com and see if the EMA portal is down for servicing or updating. If you are still unable to log in after 24 hours, contact your installer to help reset / change your user name, email address or your login password.

I forgot my password to the EMA portal/EMA App. What should I do?

Visit apsystemsema.com and click the “Lost your password?” link. You will need to know your user name.

I forgot my user name for the EMA portal/EMA App. What should I do?

Contact your installer to help reset / change your user name, email address or your login password. They have access to create and update system owner accounts.

I just bought a house with APsystems equipment and the previous owner didn’t transfer the login credentials to me, how can I access the monitoring?

Fill out the warranty transfer document form here and email it to APsystems support in your region (see your regional APsystems website for local contact info) and one of our support agents will set up EMA access for the new homeowner.

Why do my solar panels show 289w on one panel and 281w on another, is there something wrong with the inverter?

No, nothing is wrong with your inverter. The power output of the module is typically +/- 10% from module to module. In addition, the ECU gateway ‘polls’, or asks, the inverters for their power production every five minutes one-by-one, and the polling time may differ by a few minutes per solar panel so variations will happen from time-to-time.

My utility bill shows a different amount of energy produced last month than shown in the EMA portal. Why is there a difference?

The APsystems ECU gateway collects a snapshot of data from each microinverter on the DC side every five minutes during operation and was not designed to be a highly accurate revenue-grade meter (RGM). The utility company utilizes a revenue grade meter which constantly measures power production on the AC side and as such collects data in real-time. The EMA is intended to demonstrate power production, not record revenue grade data. The energy production numbers shown in the EMA are an estimate based on these infrequent intervals and will often be different than those shown in your utility bill for reasons of monitoring frequency, accuracy and what’s being measured (AC vs DC).

I see NC (No Communication) on one or more panels in the EMA. What can I do to fix it?

In case of one or more panels is showing NC, a few checks can be done: Make sure the ECU is connected to the internet. Make sure that ECU’s (ECU-R or ECU-C) antenna are not in the AC box. Try repositioning the ECU antennas (ECU-R or ECU-C) or use an antenna extension to be closer to the micros, reposition the ECU closer to the microinverters for better communication. In the case of an ECU-3 device or earlier with PLC communication (YC500 inverters), make sure you have not recently added some other devices (i.e. AC-connected devices) which can create distortion of the PLC signal and prevent proper communication between the ECU and the inverters. If so, you can try to plug in the ECU’s AC power plug (PLC) as close as possible to the PV array. You can also try using an ethernet cable to connect to the router instead of Wi-Fi. If it shows NC for more than 2 days, contact your solar installer.

In my EMA or EMA App, I don’t see power production. Can you help?

Verify that the AC breakers are in the on position, and power is connected all the way to the end of each branch circuit and that panels are clean. We do not recommend homeowners do electrical work or climb up onto the roof. We highly recommend you contact a professional solar installer to troubleshoot and repair any issues with your system.

Is my user name and password universal for the EMA online portal and the EMA APP?

Yes, the login information is the same.


What is the UID of my ECU-R, ECU-C, ECU-3, ECU-Z?

The UID or serial number is located on the back or side of the device and is a 12 digit number starting with ‘2’.

I see that you have two different communcation types; PLC and Zigbee, which ECU should I use with which product?

See the ECU & Inverter compatibility guide in our library for more information

How do I know what kind of ECU I have?

ECU-R serial numbers begin with 216
ECU-C serial numbers begin with 215
ECU-3 serial numbers begin with 203, 204, 213 or 214
See the ECU & Inverter compatibility guide in our library for more information

I have recently changed my internet provider, how do I reconnect my ECU-3 to the internet?

Please follow these guidelines.

I have recently changed my internet provider, how do I reconnect my ECU-R or ECU-C to the internet?

The ECU-R and ECU-C can be connected to the internet via hardwire ethernet cable or Wi-Fi connection. If utilizing the hardwire ethernet cable (the preferred and most reliable method) simply connect the Ethernet port on the ECU-R or ECU-C to an open Ethernet port on your router or switch. If utilizing the built-in Wi-Fi, access the ECU APP and navigate to the Settings tab, WLAN and search for available Wi-Fi, pick your router, enter the password and hit okay. See our YouTube video on the ECU-R for instructions on how to do this. (note: The ECU APP also functions with the ECU-C)

I do not have internet at my home, can I still monitor my power production?

Yes, the ECU-R has an offline monitor function (traditionally used by installers for initial set up) that can be used for system owners that do not have internet access. The offline monitoring feature can be accessed by holding the “AP” button on the side of the ECU for approximately two seconds and then releasing. This activates a Wi-Fi signal on the ECU. Then connect your smart phone to the ECU through your phone’s Wi-Fi Settings (Connect to “ECU-R_216xxxx”). Once connected, open the ECU APP (found in the App Store) and navigate to the Data tab to see Real Time Data, Power and Energy. Please note that the ECU-R has limited data memory, and, when not connected to the internet, is unable to store significant production history for later viewing. Also, APsystems always recommends that the ECU be connected to the internet (hardline or GSM router) whenever possible to ensure that the ECU and inverters can be updated to the latest software and firmware throughout the lifetime of the system.

How many PV modules can connect to a single ECU for reliable communication and management?

Approximately 100 micro-inverters can be connected to a single ECU. Which equates to approximately 200 PV modules for a dual-module microinverter, 400 PV modules for a quad.

My utility will not let me put excess power back onto the grid. Do you have function in the ECU to prevent exporting power to the grid?

Yes, you can avoid power grid reinjection/exporting by having your installer configure the ECU-C with the Zero Export function. This feature is available for three phase systems only.

I see black lines on my ECU LCD screen, how do I resolve the issue?

Move the screen from direct sunlight, reboot and observe. If that does not fix it, please contact your original solar installer.

I have an ECU and I see -W or -Web on the screen, what does that mean?

The -W or -Web means that the ECU does not have a proper internet connection. You may have an internet outage, or have recently changed your internet ISP, router, or other network settings. Please reboot the ECU, change the cable or check the internet connection. If that does not fix it, please contact your original solar installer.

What is the difference between ECU-R and ECU-C?

The ECU-R is a basic monitoring gateway, while the ECU-C has advanced functions; metering function, zero export and redundant energy control.

Can I access an ECU-R in the local area network?

No, there is no local web access to the ECU-R


Do I need the Array App?

The Array APP has been discontinued. To view your energy production, use the EMA App available in the App Store and Google Play Store.

What is the ECU App?

The ECU APP is a dedicated installer APP for initial installation and set up of the system and should not be used by system owners to monitor power production. System owners can monitor their power production using the EMA APP available in the App Store or the EMA portal online at apsystemsema.com and using the user name and password provided by your installer at the time of installation.

I noticed that you have two diffent apps in the App Store; the ECU APP and the EMA APP, what is the difference?

The ECU APP is a tool for installers to use in the initial set up of your system. The EMA APP is the monitoring tool system owners will use to monitor their energy production on their smart phone.


What is APsystems’ warranty policy for your products?

APsystems offers a:

  • 10 years standard limited product warranty on all micros-inverters. An extension of 15 years can be purchased in USA or Canada.
  • 3 years standard warranty on all ECU (gateway)
  • 1 year warranty on all accessories

Detailed warranty policy can be found by visiting our library.

What does the acronym ‘UID’ mean?

The acronym UID mean Unique IDentifier, or simply serial number.

I’m selling my home; how do I transfer the APsystems warranty to a new homeowner?

Fill out the warranty transfer document here and email it to APsystems support in your region (see your regional APsystems website for local contact info) and one of our support agents will set up EMA access for the new homeowner. If you do not know the new homeowner’s information, fill out your information in the form and provide it to the new owners for them to complete and submit to APsystems.

My electric bill has not dropped since I installed your inverters, why?

Typical system sizing does not eliminate your monthly bill, just reduces your consumption from your utility. Please review your consumption month-by-month for the past year and compare your current bill to your historical bill to see consumption reduction.

A storm has come through my area and I have lost power in my house. I installed solar power on the roof, why don’t I have power available?

The APsystems microinverter product you have installed on your roof is what is called a ‘grid-tied’ inverter and needs to sense the grid to produce power. When solar energy is produced, it is described as “use it or lose it” which means it must be immediately consumed by the energy needs of the home or exported to the grid and it cannot be saved for later unless you store it in an energy storage system. If you need power for use when the AC utility power goes out, consider adding energy storage to your home energy portfolio.

My installer is out of business/does not answer my call anymore, can you help me?

Unfortunately, this happens from time-to-time. There are many qualified solar installers in your area, please reach out to them first to help you resolve your issue. We can provide them with the information they need to be successful with our equipment. If you still cannot find a replacement installer in your area, send an email to your local support team and a customer satisfaction agent will respond with certified APsystems installers in your area that will be able to assist you.

I want to add energy storage and back-up to my system. What do you have for options / how do I proceed / what do you recommend?

APsystems inverters are agnostic and will function perfectly with all AC coupled storage solutions on the market today. We do not recommend a specific brand or model, as this is a personal choice for the features and function. Contact your solar installer for information about adding energy storage to your system.

I want to use my generator to ‘trick’ the inverters into thinking that there is a grid during a power outage, how do I set it up / is that okay?

APsystems’ microinverters are designed to be grid-tied only. APsystems does not support using microinverters in conjunction with a generator on a closed-loop system. The APsystems warranty policy clearly states that microinverters use with a generator are not covered.

Does APsystems have an open API that I can use to display data on my own website?

The API is only available for certain installers. The API calls currently available include five system level calls. Access to the API will require a unique user name and password provided by APsystems on a case-by-case basis and a yearly paid subscription is required. Contact your APsystems representative for more information. Current calls are as follows:
• Current Power
• Daily Production
• Monthly Production
• Yearly Production
• Lifetime Production

I have a large wind turbine project and want to use your microinverter, is that possible?

No, the APsystems microinverters are designed to work with todays solar PV modules, not wind turbines.