INSTALLATION AND OPERATION INSTRUCTIONS
5-8
SFC BOILER / WATER HEATERS - SFC 199
5.4 OTHER FAULTS
5.4.1 No heat (central heating) fault codes
POSSIBLE
CAUSES
ANALYSIS POSSIBLE SOLUTION
The power LED is not
shown.
→ Yes
↓No
• Check the power supply.
• Check the fuse (see Electrical schematic).
• Check wiring for breaks.
The right display
shows a line (–).
The unit is off.
→ Yes
↓No
• Switch on the unit by touching just above the power LED and
holding for 2 seconds.
Room thermostat /
outdoor sensor is
preventing call.
→ Yes
↓No
• Check the wiring. Check the Warm Weather Shut-down setting.
• Check the OpenTherm, On/Off connection of the unit, or the
connection between the central heating unit and the
OpenTherm room thermostat. Replace the thermostat.
• Replace the outdoor sensor.
No electricity (24V). → Yes
• Check the wiring according to the schematic.
• Check Connector X13.
5.4.2 Central heating does not reach the correct temperature
POSSIBLE
CAUSES
ANALYSIS POSSIBLE SOLUTION
Water pressure in the
system is too
low.
→ Yes
↓No
Top up the system.
Room thermostat is not
calling for heat.
→ Yes
↓No
Check the setting and adjust it if necessary.
Temperature is set too
low.
→ Yes
↓No
Increase the central heating temperature (see central heating
demand). If an outdoor sensor is present, check the outdoor sensor.
No ow in the system. → Yes
↓No
Check the ΔT ±36°F / ±20°C between the central heating supply and the
return. Ensure a correct ow in the system.
The unit’s capacity is
not correctly
set.
→ Yes
↓No
Adjust the unit’s capacity.
No heat transfer due to
contamination in the
central heating
unit/system.
→ Yes
↓No
Flush the central heating unit/system from the central heating side.
Flue and/or air supply
duct is blocked.
→ Yes Check and (if necessary) clean the ue and the air supply duct.
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