Nibe S2125, Installation Manual, Page: 12 / 28

Pipe connections
Pipe installation must be carried out in accordance with
current norms and directives.
The pipe dimension should not be less than the recom-
mended pipe diameter according to the table. However,
each system must be dimensioned individually to man-
age the recommended system flows.
MINIMUM SYSTEM FLOWS
The installation must be dimensioned at least to manage
the minimum defrosting flow at 100% pump operation,
see table.
Minimum re-
commended
pipe dimen-
sion (mm)
Minimum re-
commended
pipe dimen-
sion (DN)
Minimum
flow during
defrosting
(100% pump
speed (l/s)
Air/water
heat pump
28 25 0.32
S2125-8
(1x230V)
S2125-8
(3x400V)
S2125-12
(1x230V)
S2125-12
(3x400V)
An undersized system can result in damage to the
product and lead to malfunctions.
S2125 can only operate up to a return temperature of
about 65 °C and an outgoing temperature of about 75 °C
from the heat pump.
S2125 is not equipped with external shut off valves on
the water side; these must be installed to facilitate any
future servicing. The return temperature is limited by
the return line sensor.
WATER VOLUMES
Depending on the size of your S2125, an available water
volume is required to prevent short operating times and
to enable defrosting. For the optimum operation of
S2125, a minimum available water volume of 10 litres
multiplied by the size number is recommended. E.g.
S2125-12: 10 litres x 12 = 120 litres. This applies indi-
vidually to heating and cooling systems.
PIPE COUPLING, HEATING MEDIUM
You can find a list of compatible products in the section
“Compatible indoor modules (VVM) and control modules
(SMO)”.
There is a difference between connection to a control
module compared with connection to an indoor module.
See also the Installer Manual for your control module/in-
door module.
The heat pump must be vented by the upper connection
(XL1) using the venting nipple on the enclosed flexible
hose.
Install as follows:
• safety valves
• drain valve and shut-off valves
For emptying the heat pump during prolonged power
failures.
• non-return valve
• charge pump
• expansion vessel
• pressure gauge
• filterball or particle filter
Installed before the inlet, i.e. the lower connection
(XL2) on the heat pump.
• reversing valve.
When connecting to the control module, and if the
system is to be able to work with both the climate
system and the hot water heater.
• trim valve
When connecting to control module and hot water
heater.
The heat pump must be vented by the upper connection
(XL1) using the venting nipple on the enclosed flexible
hose.
P
XL1
XL2
The image shows connection to the control module.
12 NIBE S2125
IT'S IN OUR NATURE