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8.1 Safety thermostat in electrical heater
(optional equipment)
If an electrical heater suffers from a fault, the safety
thermostat will disconnect. The heater is equipped with a
fire thermostat that automatically cuts off the power
supply if the temperature exceeds 50°C. If the temperature
falls, the heater automatically re-engages.
As an additional safety measure, there is a built-in thermal
cut-out, which disengages if the temperature exceeds 100°C.
Re-engaging must be done manually.
This does not apply to PTC electrical heaters.
8.2 The system is not running
Unit stopped:
Possible error:
• Fuse in main board has blown, no power to unit
• One of the fuses on the circuit board of the unit has blown
• Loose wire, no power to unit
• Loose wire between unit and control panel
• Faulty or incorrectly set week program
• Filter timer has switched the system off
Condensed water is leaking from the unit
Possible error:
• Condensation outlet blocked by dirt
• The condensation outlet is not adequately protected
against freezing at low outdoor temperatures.
8.3 Air faults
No supply air:
Possible error:
• Faulty supply air fan
• Clogged supply air filter
• Clogged outdoor air grill due to dirt and leaves during the
fall and snow and ice during the winter.
• Fuse on the circuit board has blown
• The unit is in defrost mode (supply air fan stops)
• Incorrect value set in User Menu item 2
No extract air:
Possible error:
• Faulty extract air fan
• Clogged extract air filter
• Fuse on the circuit board has blown
8. TROUBLESHOOTING
Cold supply air:
Possible error:
• Clogged heat exchanger
• Faulty extract air fan
• Clogged extract air filter
• The electrical reheater is disconnected from the
overheating thermostat (only units with electrical
reheater installed).
• Air in the heating pipes, faulty thermostat/motor valve,
incorrect setting of control panel
