The novolto immersion heater

You can download the instruction manual as a PDF here (German).

Automatic surplus solar power control requires a supported measurement solution, such as a compatible Shelly device, Tibber Pulse or poweropti, or a suitable system connected through MQTT. Check that your chosen solution works with your electricity meter and is supported by novolto before purchasing.

With a smart immersion heater, you can use surplus solar power for water heating instead of feeding it entirely into the grid. This allows you to increase your PV system's self-consumption and relieve the existing hot water generation system during times with sufficient surplus solar power.

The novolto immersion heater is installed horizontally in a suitable domestic hot water or buffer storage tank and converts electrical energy directly into heat. In automatic mode, the heating output is adjusted to the available surplus solar power based on the power measured at the electricity meter. Additionally, the immersion heater can be operated manually via the novolto app.

The terms immersion heater, heating cartridge, and screw-in immersion heater are sometimes used interchangeably in everyday language. Technically, however, design, connection, and installation method can differ. The novolto immersion heater is a screw-in heater with a G 1 1/2" connection for horizontal installation.

A solar thermal system uses solar energy to heat domestic hot water and/or heating water. A photovoltaic system generates electricity for use in your own home – excess power is generally fed into the grid. The smart immersion heater absorbs this surplus electricity and uses it to heat your domestic water.

An integrated temperature sensor measures the temperature at the immersion heater's screw-in point. A target temperature can be set via the novolto app. The control system operates with a total on/off range of 5 °C to prevent the immersion heater from constantly switching on and off.

The novolto immersion heater is designed for operating temperatures of up to 80 °C. Additionally, it features a safety temperature limiter (STB) that triggers at a critical temperature of 95 °C (+0/-6 °C).

You can set a target temperature via the novolto app. An integrated sensor measures the temperature at the screw-in point. The immersion heater switches off at the target temperature plus 2.5 °C and begins heating again when the temperature falls 2.5 °C below the target value. This results in a switching range of 5 °C.

For orientation, you can apply the following rule: 1.16 kWh heats 100 liters of water by 10 °C. This means: If a 2.3 kW immersion heater runs for one hour, the water temperature will rise by approximately 20 °C.

This rule of thumb assumes idealized conditions without heat loss. With higher output or smaller storage volume, the time is shortened accordingly; conversely, it is extended.

In practice, insulation, ambient temperature, and circulation can influence the heating duration.

Yes, the immersion heater can also be operated with mains power. If your property does not have a photovoltaic system, you can use power from the grid. Or use a mix of PV power and mains power. With the app, you can set a desired heating output and duration at any time.

Self-installation is only appropriate if your tank and electrical setup are suitable and local rules allow it. Follow the installation manual. Use a qualified installer where required or if you are unsure.

Requirements:

• 1.5" socket on the storage tank is available (or flange with socket)
• Power outlet nearby

Tools:

• Open-ended wrench or pipe wrench
• Sealant (Teflon tape or hemp with sealing paste)

Essential steps:

• Switch off the heating
• Shut off the cold water supply
• Release pressure (open a higher-positioned draw-off point, such as a faucet)
• Drain water down to the installation height
• Insert the immersion heater into the socket, screw it in with a thread seal, and align it straight
• Refill the water and check for leaks
• Put the heating back into operation
• Connect the immersion heater to the power outlet

The smart immersion heater is equipped with a standard connection thread:
1.5" (inch) or 6/4" (inch).

By checking your storage tank's product description, you can often determine for yourself whether a 1.5" (inch) threaded sleeve is available into which you can screw the immersion heater.

Even without the 1.5" sleeve, installation is possible if your storage tank has a maintenance hatch or an inspection port. In that case, a flange can be installed in place of the hatch cover, into which the smart immersion heater can be screwed.

First, the smart immersion heater must be properly installed in your hot water or buffer tank and connected to a power outlet. Please note that the power cable is 2.85m long.

Second, you need Wi-Fi reception near the immersion heater, or a LAN cable must be routed to the immersion heater.

For automatic control that activates the immersion heater when you generate more PV power than you consume, a reader for your electricity meter is required. This reader must be installed and operated on your electricity meter. Our immersion heater is compatible with the Tibber Pulse IR, poweropti, and Shelly metering devices; further integrations will follow.

The smart immersion heater is installed in a fixed position in your hot water or buffer tank. You must drain your tank, screw in the immersion heater so that it is thread-sealed, and then refill the tank. Afterwards, you can put the immersion heater into operation.

Be sure to follow the instructions in the included installation manual. It contains all the relevant information regarding intended use, location selection, preparation, execution, and completion of the installation.

The smart immersion heater can be connected to a standard earthed socket (also known as plug type F or CEE 7/4).

The power cable is 2.85m long.

The heating output is controlled virtually steplessly in 20 W increments. The novolto P2300 provides up to 2,300 W, the P3000 up to 3,000 W. Both operate at 230 V; for the P3000, approximately 13 A can flow at full power. The circuit used must be sufficiently dimensioned and fused for this purpose.

From left to right, the symbols represent the following areas:

First, LED Connection: connection status of the smart immersion heater.
Second, LED System: operating and safety status of the system.
Third, LED Heating: activity of the heating elements.

Please refer to the user manual to understand the color codes for each symbol/LED.

Wi-Fi
Press the Connection button (on the bottom of the immersion heater, to the right of the power cable). The device will then set up an access point (Connection LED pulses blue). Using a Wi-Fi-enabled device, search for a network named "NOVOLTO-******" and connect to it. Then, scan the supplied QR code (No. 1) or visit the address http://192.168.2.1. Follow the instructions on the page.

LAN
Unplug the power cord and connect the LAN cable to the RJ45 port (on the bottom of the immersion heater, left side). Then reconnect the power supply. The immersion heater will automatically connect to the novolto server.
Note: DHCP must be enabled on your router for automatic IP address assignment.

Once successfully connected to your Wi-Fi or LAN, the Connection LED will pulse green.

Yes. For technically proficient users, local control via MQTT is possible. This allows control commands to be transmitted within the local network. The settings required for this are provided by novolto upon request via info@novolto.de.

First, register your immersion heater with its serial number and PIN in the novolto app. Then, connect the supported measuring solution there. Depending on the provider, activation takes place via the respective login or authorization process. You can find out which electricity readers are currently supported on the electricity reader page.

With your customer account, we grant you access to the novolto app and, above all, ensure that only you can control your smart immersion heater.

At https://novolto.app you can open your customer account for the app and then use it.

First, you need to register your immersion heater. For this, you will need the serial number and PIN. You can either use the provided QR code (No. 2) or enter the data manually. The PIN is located below the QR code, and the serial number is above the QR code. You can also find the serial number on the type plate on your immersion heater.

Next, enter your user details and create a login and password.

You can use your login and password to sign in to the app at any time and adjust settings for your immersion heater.

iOS/Apple/Safari
After opening the app in the Safari browser, please select "Add to Home Screen [+]."

Android/Google
After opening the app in the Chrome browser, tap the three small dots in the top right corner to open the menu. Select "Add to home screen."

Currently, the automatic surplus control is designed for one target device per integrated measurement solution. If you would like to operate multiple immersion heaters in one property, please clarify the desired configuration with novolto in advance.

In automatic mode, the immersion heater adjusts its output based on the measured surplus power. Control starts from 20 W and is intended to utilize the available surplus solar power as accurately as possible. A separate minimum switching threshold cannot be freely adjusted in the current app.

First, connect the immersion heater to your network via Wi-Fi or LAN and then register it in the novolto app using the serial number and PIN. For automatic operation, a supported electricity meter measurement solution is also integrated. This allows the controller to detect when surplus solar power is available.

The novolto immersion heater can be controlled via two operating modes:

1. Automatic control:
Even if you never use the novolto web app again after installation, your immersion heater will activate automatically when your electricity meter detects "surplus solar power."

2. Manual control:
However, if you would like to control your immersion heater individually, you can activate it in your novolto web app for a selected period with a custom wattage. Your immersion heater will then operate until the end of the selected period or until your target temperature is reached. If you would like to switch it off beforehand, this is of course also possible.

The heating pipes are made of Incoloy 825 / material 2.4858, a corrosion-resistant material. Nevertheless, limescale deposits can form, especially with hard water and high temperatures. Therefore, check the immersion heater and storage tank as part of the maintenance scheduled for your system and water hardness, and remove deposits if necessary. The required intervals depend on water quality, temperature, and usage.

There is a problem if one of the three symbols on the immersion heater's display lights up red. The red-illuminated symbol provides information about which problem is present:

LED Connection lights up red: No Wi-Fi/LAN connection. Start commissioning the device according to the operating manual.

LED System lights up red: Temperature sensor or power control defective. The product must be repaired. Please contact us!

LED Heating lights up red: The safety temperature limiter (STB) has been triggered (at a water temperature of 95 °C +0/-6 °C).

Our immersion heaters are designed for a long service life of several years. The exact service life depends on factors such as water quality, frequency of use, and maintenance.

The immersion heater features temperature monitoring and a mechanical safety temperature limiter (STL). The integrated temperature sensor is also used for normal temperature control. In the event of a safety-relevant shutdown or a red system indicator, please refer to the operating manual and do not continue to operate the device if it is defective.

In the event of a power failure, the immersion heater remains switched off. After power is restored, it resumes operation according to the previous settings.

The circuit must be sufficiently dimensioned for the maximum power consumption of the model used and properly fused. The P2300 requires approximately 10 A at full power, and the P3000 requires around 13 A at 230 V. Avoid overloading by using other large appliances on the same circuit. If you cannot safely assess the existing installation, have the circuit checked by a qualified electrician.