
• Low hot water access with the “Smart Control”
function active.
– If the hot water usage has been low for an extended
period of time, S1155/S1255 will produce less hot water
than normal. Activate "More hot water" in menu 2.1.
• Too low or no operating prioritisation of hot water.
– Contact your installer!
• "Holiday" activated in menu 6.1.
– Enter menu 6.1 and deactivate.
LOW ROOM TEMPERATURE
• Closed thermostats in several rooms.
–Set the thermostats to max in as many rooms as possible.
Adjust the room temperature via home screen heating,
rather than choking the thermostats.
• S1155/S1255 in incorrect operating mode.
– Contact your installer!
• Too low set value on the automatic heating control.
– Go to the Smartguide for help in increasing heating. You
can also change the heating from the home screen heat-
ing.
• Too low or no operating prioritisation of heat.
– Contact your installer!
• "Holiday mode" activated in menu 6.1.
– Enter menu 6.1 and deactivate.
• External switch for changing room temperature activ-
ated.
– Check any external switches.
• Air in the climate system.
– Vent the climate system.
• Closed valves to the climate system.
– Open the valves (contact your installer for assistance in
finding them).
HIGH ROOM TEMPERATURE
• Too high set value on the automatic heating control.
– Go to the Smartguide for help in decreasing heating. You
can also change the heating from the home screen heat-
ing.
• External switch for changing the room temperature
activated.
– Check any external switches.
UNEVEN ROOM TEMPERATURE.
• Incorrectly set heating curve.
– Fine-tune the heating curve in menu 1.30.1.
• Too high set value on "dT at DOT"..
– Contact your installer!
• Uneven flow over the radiators.
– Contact your installer!
LOW SYSTEM PRESSURE
• Not enough water in the climate system.
– Fill the climate system with water and check for leaks. In
event of repeated filling, contact the installer.
THE COMPRESSOR DOES NOT START
• There is no heating or cooling demand (accessory is
required for cooling).
– S1155/S1255 does not call on heating, cooling or hot wa-
ter.
• Compressor blocked due to the temperature condi-
tions.
–Wait until the temperature is within the product’s working
range.
• Minimum time between compressor starts has not
been reached.
– Wait for at least 30 minutes and then check if the com-
pressor has started.
• Alarm tripped.
– Follow the display instructions.
WHINING NOISE IN THE RADIATORS
• Closed thermostats in the rooms and incorrectly set
heating curve.
–Set the thermostats to max in as many rooms as possible.
Fine-tune the heating curve via home screen heating,
rather than choking the thermostats.
• Circulation pump speed set too high.
– Contact your installer!
• Uneven flow over the radiators.
– Contact your installer!
Only additional heat
ADD. HEAT ONLY
If you are unsuccessful in rectifying the fault and are
unable to heat the house, you can, whilst waiting for
assistance, continue running the heat pump in emer-
gency mode or "Additional heat only" mode. "add. heat
only" mode means that the heat pump only uses the
immersion heater to heat the house.
Set the heat pump to additional heat mode
1. Go to menu 4.1 "Operating mode".
2. Select "Additional heat only".
NIBE S1155/S1255Chapter 6 | Disturbances in comfort14