Cutting the chords to the outdoor sensor?

When installing Ngenic Tune, the Y-cable is connected between the outdoor sensor and the heating system. This is usually done by cutting the outdoor sensor cable, but if the cable already has an accessible joint, you do not need to cut it.

Already have a cable joint? No cutting is needed

District heating systems often have an existing cable joint or terminal block between the outdoor sensor and the heating regulator, as shown below. You can disconnect the cables there and connect the Y-cable instead. You do not need to cut the outdoor sensor cable or remove the connectors from the Y-cable.

1. Switch off the heating system before changing any connections.
2. Identify which cable end leads to the outdoor sensor and which leads to the regulator/heating system. Take a photo of the existing connection before disconnecting anything.
3. Disconnect the conductors of both cable ends from the existing joint terminal block.
4. Connect the conductors leading to the outdoor sensor to the Y-cable connector marked with a tree.
5. Connect the conductors leading to the regulator/heating system to the Y-cable connector marked with a house. The Y-cable now replaces the original joint.
6. Check that the conductors are firmly secured and connect the Y-cable's 3.5 mm plug to the Ngenic controller. Then switch the heating system back on.

If the cable contains more than two conductors, follow the installation guide to identify and group them correctly.

Example before installing Ngenic Tune: the existing joint terminal block can be replaced by the Y-cable connectors. The Swedish labels identify the upper cable as the outdoor sensor cable, to be connected to the tree marking (“gran”), and the lower cable as the regulator cable, to be connected to the house marking (“hus”). The top caption explains that no cutting is needed when a joint is already present. Always check the cable routing in your own system.

House = regulator/heating system. Tree = outdoor sensor.

If there is no existing cable joint

You can follow the standard installation and cut the outdoor sensor cable. Switch off the heating system first. Cut close to the heating system, preferably within three metres, leaving enough cable on both sides for the connections. The Ngenic controller must be placed indoors. Then follow the installation guide to connect the cable ends to the Y-cable.

The outdoor sensor cable is often thin, white or grey, and runs from the heating system through a wall or ceiling to the outdoor sensor, usually on the north-facing exterior wall. Identify it by checking where it leads, not by colour alone.

Alternative: connect directly to the heating system terminal block

If there is no separate joint and you still want to avoid cutting the cable, you can connect the Y-cable directly to the heating system terminal block:

1. Switch off the heating system.
2. Disconnect the outdoor sensor cable from the heating system terminal block. Note the two terminals it was connected to.
3. Remove the connector from the Y-cable end marked with a house and connect its conductors to those same two terminals.
4. Connect the outdoor sensor conductors to the Y-cable end marked with a tree.
5. Connect the Y-cable's 3.5 mm plug to the Ngenic controller and switch the heating system back on.

After installation, the heating system should be able to display the outdoor temperature if it has a suitable display. If you are unsure which cable or terminals belong to the outdoor sensor, contact support@ngenic.se before changing the connections.