Auto Fan - Δ settings

The diagram below shows how the actual fan speed changes when the user has set the fan to auto.

Example: - current operational mode: Heating - Δt1 = 1°C - Δt2 = 1°C => 20% Δt2 = 0.2°C - Δt3 = 1°C => 20% Δt3 = 0.2°C - target temperature (w) = 23°C - threshold temperature 1 (th1) = w-Δt1 = 23 - 1 = 22°C - threshold temperature 2 (th2) = th1-Δt2 = 22 - 1 = 21°C - threshold temperature 3 (th3) = th2-Δt3 = 21 - 1 = 20°C - measured temperature = 22.2°C

1. When the measured temperature drops from 22.2 to 22°C (threshold temperature 1 - th1) or lower, the valve(s) fan goes into Low speed mode

2. The temperature keeps dropping to 21°C (threshold temperature 2 - th2), the fan goes into Medium speed mode

3. The temperature drops further to 20°C (threshold temperature 3 - th3), the fan goes into High speed mode

4. Temperature starts increasing till it reach 20.8°C (20%Δt3 threshold), where the fan speed is reduced to Medium.

5. Temperature increases further till it reach 21.8°C (20%Δt2 threshold), where the fan speed is further reduced to Low.

6. Temperature increases still, reaching 23°C (target temperature - w), the Fan turns off.

Delta temperature 1 (ΔT1)

You can change the delta temperature (ΔT1) with the following command set.

SET

You can set the delta temperature (ΔT1) with the command:

Byte index	Hex value – Meaning
0	6A – The command code.
1	XX - ΔT1[°C] * 10. Default value: 0x0A (1,0°C)

Example command: 0x6A0F;

0x0F[HEX] = 15[DEC] => ΔT1 = 15 / 10 = 1,5°C.

GET

This command gets the target temperature step. The keepalive data in the example below is omitted for clarity.

Byte index	Sent request	Received response
0	6B – Command code	6B – Command code.
1		XX - ΔT1[°C] * 10.

ΔT1[°C] = XX / 10;

Example command: 0x6B;

Example response: 0x6B0F;

0x0F[HEX] = 15[DEC] => ΔT1 = 15 / 10 = 1,5°C.

The allowed ΔT1 range step is 0,5...10°C (0,5°C resolution).

Delta temperatures 2 (ΔT2) and 3 (ΔT3)

You can change the delta temperatures (ΔT2) and (ΔT3) with the following command set.

SET

You can set the delta temperatures (ΔT1) and (ΔT3) with the command:

Byte index	Hex value – Meaning
0	6C – The command code.
1	XX - ΔT2[°C] * 10. Default value: 0x0A (1,0°C)
2	XX - ΔT3[°C] * 10. Default value: 0x0A (1,0°C)

Example command: 0x6C0F14;

Set the ΔT2 = 1,5°C - 1,5 * 10 = 15[DEC] => 0x0F[HEX].

Set the ΔT3 = 2,0°C - 2 * 10 = 20[DEC] => 0x14[HEX].

GET

This command gets the target temperature step. The keepalive data in the example below is omitted for clarity.

Byte index	Sent request	Received response
0	6D – Command code	6D – Command code.
1		XX - ΔT2[°C] * 10.
2		XX - ΔT3[°C] * 10.

Example command: 0x6D;

Example response: 0x6D0F14;

ΔT[°C] = XX / 10;

0x0F[HEX] = 15[DEC] => ΔT2 = 15 / 10 = 1,5°C.

0x14[HEX] = 20[DEC] => ΔT3 = 20 / 10 = 2,0°C.

The allowed (ΔT2) and (ΔT3) range step is 0,5...10°C (0,5°C resolution).