- 8 -
- 9 -
1-5 Main Safety Devices
1. Water Flow Sensor (Boil-dry protection)
When the Water Flow Sensor detects the flow rate is set for starting ignition (ignition
water flow) or higher, the water heater starts operation.
Ignition water flow : 2.7 L/min.
Extinction water flow : 2.2 L/min.
2. Flame Sensor (Flame failure detection)
Electric signals are transmitted to the flame detection circuit to confirm the normal
combustion when the Flame Sensor detects the rectification of normal combustion
flame. Therefore, if the combustion of the Burners is not normal, the signals are not
sent via the Flame Sensor. The gas control assemblies are closed without the signals
and the error code "111" or "121" is displayed on the remote controllers.
3. Thermal Fuse (Over-temperature protection system)
The Thermal Fuse is placed around the Primary Heat Exchanger Assembly. If the
ambient temperature inside the water heater becomes extremely high, the fuse will
melt down to break the power circuit. In such a case, as no power is supplied to the
gas control assemblies, the gas supply is stopped and the combustion is stopped.
(The system is activated to blow the fuse at 169°C.)
4. Over Heat Thermostat (residual)
Even if the Primary Heat Exchanger Assembly is over heated by no-water combustion,
every gas path is closed to avoid risks. At this time, the error code "141" is displayed
on the remote controllers.
(The switch is provided with a auto-restoration function and turns OFF at 100°C.)
5. Fan Revolution Detection Device (Hall IC)
The device detects the fan revolution speed to control the air supply necessary for
normal combustion. If the fan revolution is out of the preset standard range, the gas
control assemblies are closed to stop the combustion before combustion failure
occurs. In this case, the error code "611" is displayed on the remote controllers.
6. Freeze Protection System (Anti-Frost Heaters)
To prevent freezing in the hot water supply circuit, Anti-Frost Heaters are provided at
major points of water flow paths in the unit. The heaters are activated by the Ambient
Temperature Sensor in the unit.
(The system turns ON at 3°C and OFF at 13°C.)
