Nibe F2025, Installation And Maintenance Instructions Manual, Page: 24 / 56

Adjustment, charge flow
Adjusting the temperature difference (
Δ
T) between the flow
temperature and the return temperature during hot water
charging or at high load.
This is easily done by using the temperatures measured in
Channel T2 (flow temperature) less Channel T3 (return tem-
perature), this temperature difference (
Δ
T) is adjusted using
circulation pump and control valve. Adjustment is performed
with stable operation about 5 minutes after start, or about
5 minutes after defrosting with a cold outdoor temperature.
The temperature difference must be as in the diagram below
(+1- 2 K). At outdoor temperatures above 28 °C the charge
flow can be increased by 30 % to obtain a lower
Δ
T.
The diagrams show the heat pump with a high fan speed,
at low fan speeds
Δ
T will be 0.5 to 1 degrees lower (does
not apply to F2025-6 kW, which only has one fan speed).
1 and 4 flow temperature. 35°
2 and 5 flow temperature. 45°
3 and 6 flow temperature. 55°
F2025-6
-20 -15 -10 -5 0 5 10 15 20 25 30
2
0
4
6
8
10
12
1
2
3
6
5
4
2
4
6
8
10
12
14
-20 -15 -10 -5 0 5 10 15 20
16
25 30
1
2
3
18
20
Δ T
Phase current, A
Specified output, kW
Outdoor temperature Outdoor temperature
Rated output
Phase current
F2025-8
2
3
4
5
6
7
8
9
10
11
12
-20 -15 -10 -5 0 5 10 15 20
1
2
3
6
5
4
25 30
13
14
15
2
4
6
8
10
12
14
-20 -15 -10 -5 0 5 10 15 20
16
18
25 30
1
2
3
Δ T
Phase current, A
Specified output, kW
Outdoor temperature Outdoor temperature
Rated output
Phase current
F2025 22
For the Installer
Commissioning and adjusting