Thermostat replacement

Feb 18, 2023 Last reply: 3 years ago 4 Replies

In a Siemens thermostat with 5 wires, the purpose of each wire is typically as follows:

  1. N - This wire is the neutral wire and is typically connected to the neutral wire of the electrical supply.
  2. L - This wire is the live wire and is typically connected to the live wire of the electrical supply.
  3. L1 - This wire is usually used to provide power to the thermostat and is typically connected to the power supply output of the heating system.
  4. LX - This wire is used as a control wire and is typically connected to the heating system's control circuit.
  5. L2 - This wire is also typically used to provide power to the thermostat and is connected to the other output of the heating system's power supply.

The specific function of each wire may vary depending on the particular Siemens thermostat model and the heating system it is being used with. It is important to refer to the installation instructions provided with the thermostat or consult a professional electrician or HVAC technician to ensure proper and safe installation.

I do not have experience connecting a Hive Thermostat myself, but it appears to have terminals labeled as N: Permanent neutral L: Permanent live 1: Common 2: Heating OFF (NC) 3: Heating ON (NO)

So, to connect a thermostat with the following connections to a heating system with N, L, L1, LX, L2 wires, you can typically make the following connections:

  1. Connect the Permanent Neutral wire from the thermostat to the N wire in the heating system.
  2. Connect the Permanent Live wire from the thermostat to the L wire in the heating system.
  3. Connect the Common wire (1) from the thermostat to the L1 wire in the heating system.
  4. Connect the Heating on (NO) wire (3) from the thermostat to the LX wire in the heating system.
  5. Connect the Heating off (NC) wire (2) from the thermostat to the L2 wire in the heating system.

or something like this in a table: 

 Siemens | Hive 3

N | N: Permanent neutral L | L: Permanent live L1 | 1: Common LX | 3: Heating on (NO) L2 | 2: Heating off (NC)

  Hope this helps!

Will try this tonight after work thanks for your help

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