Installation: Enphase SG Ready Vaillant aroTherm plus Heat Pump System Instruction Manual

Overview

The SG Ready Vaillant aroTherm plus Heat Pump System guide explains how to connect and configure compatible Vaillant aroTHERM plus heat pumps with an Enphase IQ Energy Router, SG Ready Relay, and Energy Meter. The arrangement is intended for qualified heating and electrical installation professionals who are commissioning solar-assisted home energy management.

When correctly installed, the SG Ready interface allows the energy management system to recommend operation of the heat pump when surplus solar electricity is available. This can increase solar self-consumption while preserving normal heat-pump control and household comfort.

This guide applies to supported aroTHERM plus systems using the listed Vaillant indoor units or controllers. It does not replace the installation, operating, or safety instructions supplied for the Vaillant heat pump, indoor unit, controller, or Enphase equipment.

Specifications

• Supported heat pump: Vaillant aroTHERM plus VWL 105/6 A 230V S2.
• Supported heat pump: Vaillant aroTHERM plus VWL 125/6 A S2.
• Compatible indoor units and interfaces: VWZ MEH 97/6, uniTOWER plus VIH QW 190/6 (E), and VWZ AI, depending on the heat-pump configuration.
• Compatible system controllers: Vaillant multiMATIC 700 and sensoCOMFORT 720, where installed.
• Required Enphase equipment: IQ Gateway, IQ Battery, IQ Microinverters, IQ Energy Router, Energy Meter, and SG Ready Relay.
• Network requirement: the SG Ready Relay and Energy Meter must be connected to the same local area network.
• Supported SG Ready states through the Enphase integration: state 2, Normal, and state 3, Recommended.
• Supported wiring modes: SG Ready modes 1, 2, and 3. Mode 4 is not supported by the described wiring arrangement.

Detailed Description

The SG Ready interface uses switching contacts to communicate an operating recommendation to the heat-pump system. The Enphase IQ Energy Router evaluates the energy system and can use the SG Ready Relay to request the recommended operating state when conditions are suitable for using available solar energy.

The Enphase integration does not use the SG Ready states that switch the heat pump forcibly off or forcibly on. State 3 is a recommendation rather than an unconditional command, so the Vaillant system retains control over whether operation is appropriate. Normal heating, hot-water production, safety functions, and system protection remain governed by the heat-pump controller.

The installation can connect to either the control PCB in a VWZ MEH 97/6 indoor unit or uniTOWER plus VIH QW 190/6 (E), or directly to a VWZ AI controller. The connection method depends on the equipment fitted in the specific installation.

Safety

Electrical installation must be completed by qualified personnel. The SG Ready Relay contains no user-serviceable parts. Do not dismantle, repair, modify, or use it outside its specified purpose.

• Disconnect the heat pump, Energy Meter, SG Ready Relay, and associated circuits before opening equipment or changing wiring.
• Isolate the installation with the appropriate circuit breaker or main fuse, verify that no voltage remains, and prevent accidental reconnection.
• Remember that some conductors may remain energized after the main supply is switched off.
• Do not touch live components or work alone near electrical equipment.
• Inspect wiring for correct termination, damage, and pinching before closing an enclosure.
• Use electrical components approved for the installation environment, including wet locations where applicable.
• Remove conductive jewellery such as rings, watches, bracelets, and necklaces before electrical work.
• Follow all national and local electrical codes and the safety instructions for the Vaillant and Enphase products.
• Do not set domestic hot-water temperatures unnecessarily high, because excessive temperatures can cause discomfort or injury.

Setup and Operation

Prerequisites

Complete the Enphase Home Energy Management installation and commissioning procedure before configuring the heat pump. Activate the IQ Energy Router and configure it to detect the SG Ready Relay and Energy Meter.

Install the supported Vaillant heat-pump system and the required Enphase equipment. The SG Ready Relay and Energy Meter must communicate through the same customer network.

Connecting to the VWZ MEH 97/6 or uniTOWER plus

1. Switch off and isolate the complete installation. Verify that no dangerous voltage is present.
2. Remove the screws securing the front cover of the VWZ MEH 97/6 or uniTOWER plus VIH QW 190/6 (E), then remove the cover.
3. Open the control PCB electronics box by hinging it forward and releasing its retaining clips.
4. Connect the SG Ready Relay conductors to the following control PCB points:

• SG Ready Relay output 25 to X106/S21:3.
• SG Ready Relay output 26 to X106/S21:4.
• SG Ready Relay output 28 to X41/FB.
• SG Ready Relay output 29 to X41/OT.

The wire colours are not significant for this connection; the terminal locations and correct electrical installation are essential.

After completing the wiring, close the electronics box, refit the front cover, and secure all screws before restoring power.

Connecting to the VWZ AI Controller

1. Isolate the system and confirm that the controller is not energized.
2. Remove the screws and front cover from the VWZ AI.
3. Connect the SG Ready Relay to the EVU and ME inputs as follows:

• SG Ready Relay output 25 to EVU:1.
• SG Ready Relay output 26 to EVU:2.
• SG Ready Relay output 28 to ME:1.
• SG Ready Relay output 29 to ME:2.

Wire colours are not important for this connection, but each conductor must be installed on the specified terminal. Refit the cover and secure the enclosure before energizing the equipment.

SG Ready Operating Modes

• Mode 1, combination 1:0: the heat pump and electrical auxiliary heater are off.
• Mode 2, combination 0:0: normal heat-pump operation according to the controller settings.
• Mode 3, combination 0:1: a recommended one-time storage-tank charge is requested. The system can charge the hot-water tank and, when available, raise the buffer-tank temperature according to the configured setpoints.
• Mode 4, combination 1:1: not supported by the wiring arrangement described in this guide.

For the VWZ MEH 97/6 or uniTOWER plus connection, the first contact is X106/S21 and the second contact is represented by the X41/FB and X41/OT inputs. For the VWZ AI, the corresponding contacts are EVU and ME.

Restoring Power

After checking the wiring and closing all covers, restore power to the heat pump, Energy Meter, and SG Ready Relay by closing the appropriate breakers. Continue with controller configuration only after the equipment has restarted normally.

Configuring the multiMATIC 700

1. Open the controller menu.
2. Enter the installer level and enter the access code. The documented factory code is 000; an installer should be consulted if the code has been changed and is unavailable.
3. Open System configuration, then System, and select Energy supplier.
4. Choose HP&BH off and confirm the selection.
5. Return to Additional module, open Multi-funct. Input, and select PV.
6. Open the buffer-cylinder offset setting and configure the temperature increase used while the SG Ready signal is active.
7. Return to the main menu after saving the settings.

The documented guidance is typically +5 K for domestic hot water and the heating-water buffer cylinder, and +1.5 K for room temperature. These are guidance values rather than universal settings; the installer should agree the final offsets with the homeowner and ensure that hot-water temperatures remain safe.

Configuring the sensoCOMFORT 720

1. Open the main menu and select Settings.
2. Enter the installer level using the access code. The documented factory code is 00; use the responsible installer if the code has been changed and is unknown.
3. Open Installation configuration, then Installation, and select ESCO.
4. Choose HP + BUH off and confirm.
5. Open HP control module configuration, select MI, and choose Photovoltaics.
6. Open Buffer cylinder offset and set the temperature offset for active SG Ready operation.
7. Save the settings and return to the main menu.

As guidance, the documented values are +5 K for domestic hot water and the heating-water buffer cylinder, and +1.5 K for room temperature. The final values should suit the building, heat emitters, hot-water requirements, and homeowner preferences.

Testing the Energy Meter

1. Use the customer router to identify the IP address assigned to the Energy Meter. The address is normally assigned dynamically through DHCP.
2. Enter the Energy Meter IP address in a browser on a computer, tablet, or smartphone connected to the network.
3. Use the factory password printed on the Energy Meter nameplate or supplied nameplate documentation.
4. Open the dashboard and check live power, current, voltage, and power-factor readings for each measured phase.
5. Keep the Energy Meter interface open while testing the SG Ready Relay.

Testing the SG Ready Relay

1. Press the Select button on the SG Ready Relay.
2. Select LED 2 so that it flashes.
3. Press and hold OK for one second.
4. Confirm that SG Ready operating state 3 is enabled.
5. On a sensoCOMFORT 720, check for the indication that hot-water boost is active. The heat pump may take several minutes to start.
6. On a multiMATIC 700, controller confirmation of this test is not available.
7. Return to the Energy Meter dashboard and confirm a plausible live consumption value above 0 kW when the heat pump is operating. Check each connected phase for reasonable readings.

To end the test, select LED 2 again and hold OK for one second. LED 2 should then glow red. If the heat pump has not started immediately, allow several minutes for the controller to respond to the manually selected SG Ready state.

Commissioning Home Energy Management

After the electrical connections, controller settings, Energy Meter test, and SG Ready Relay test are complete, open the Enphase Installer App and use its support area to complete the Home Energy Management commissioning sequence.

Troubleshooting

• The Energy Meter cannot be found: confirm that it is powered, connected to the customer network, and receiving an IP address from the router. Verify that the SG Ready Relay and Energy Meter are on the same local area network.
• No live Energy Meter readings appear: check the meter supply, network connection, login details, and phase wiring. Readings should be plausible for the connected phases.
• The heat pump does not start during the SG Ready test: confirm that LED 2 was selected and that OK was held for one second. Wait several minutes because the controller may delay operation.
• State 3 is not recognized: check the SG Ready Relay wiring against the correct indoor-unit or VWZ AI terminal arrangement, then verify the PV or Photovoltaics controller setting.
• The installer menu cannot be opened: verify the appropriate controller access code. If the factory code has been changed, the responsible heat-pump installer must provide the authorized procedure.
• Domestic hot water becomes excessively hot: reduce the configured offset and have the installer check the controller settings. Do not use unnecessarily high hot-water temperatures.
• The relay or heat-pump test fails: isolate the system before inspecting wiring. Do not dismantle or repair the SG Ready Relay; defective equipment requires qualified service handling.

Pros & Cons

• Pros: supports solar-energy self-consumption, works with selected Vaillant aroTHERM plus configurations, provides a defined SG Ready recommendation path, and allows storage charging to be coordinated with surplus energy.
• Pros: normal heat-pump control remains active because the integration uses the Normal and Recommended states rather than forcibly controlling every operating state.
• Cons: compatibility depends on the exact heat-pump indoor unit, controller, and wiring arrangement.
• Cons: installation requires work inside electrical enclosures and must be performed by qualified personnel.
• Cons: SG Ready mode 4 is unavailable with the described connections, and the multiMATIC 700 does not provide a controller display confirmation during the relay test.

Maintenance and Documentation

Keep the SG Ready Relay, Energy Meter, heat-pump controller, and electrical enclosures accessible for qualified inspection. Before any maintenance, isolate the complete system and verify the absence of voltage. Follow the separate Vaillant maintenance instructions for the heat pump and indoor unit, and the applicable Enphase instructions for the energy-management equipment.

Dispose of electrical equipment through suitable recycling channels rather than household waste. Product information and controller menus can change between revisions, so installers should use the current documentation applicable to the exact equipment fitted.