There Is No Hot Water; "Fault" Is Shown In The Display - Viessmann VITOLIGNO 250-S Operating Instructions Manual

There is no hot water

Cause
Control unit incorrectly set.
DHW cylinder is cold.
The DHW cylinder and boiler water temperature is too
low.
The DHW cylinder pump is not running.
Mixing valve faulty
The DHW is too hot
Cause
Control unit incorrectly set.
Sensor fault

"Fault" is shown in the display

Cause
Heating system fault
is displayed
Cause
Lambda probe deactivated. Emergency mode is active.
Remedy
Check the settings and correct if required:
DHW heating must be ON (see page 28)
■
DHW temperature (see page 28)
■
Time (see page 32)
■
Switching times (see page 28)
■
Check the settings and correct if required:
Set DHW temperature (see page 28)
■
Heating times for DHW heating (see page 29)
■
If the heating times are OK: Check the temperature of
the DHW cylinder. If this temperature is too low: Heat
up the boiler (see page 15).
Charge the boiler with fuel. Heat up the boiler (see
page 15).
Check the heating times. If according to the times set in
the control unit the pump should be running: Notify your
heating contractor.
Notify your heating contractor.
Remedy
Check and correct the DHW temperature if required
(see page 28).
Notify your heating contractor.
Remedy
Check the type of fault (see page 37) and notify your
heating contractor.
Remedy
Notify your heating contractor. The Lambda probe re-
quires calibration.
What to do if...
41