Desa Master WA 33 Operating Manual page 35

operates until the furnace temperature is below 35°C (damping). After the temperature reaches less than
35°C, the furnace returns to the Stop phase.
The furnace may be switched off automatically in the following cases:
- overheating of the combustion chamber
- overflow
The overheating signal is generated by the bimetallic sensor placed nearby the fan. The opening of the
contacts is signalled by the exceeding the threshold temperature value. The control system switches off
the pump (the operation indicator of the pump is not back-lit – yellow diode), the overheating state is
signalled by the red diode, which is back-lit on the control panel. The air exhaust fan operates until the
furnace temperature drops below 35°C. After reaching the temperature lower than 35°C, the furnace
returns to the Stop phase.
After switching to the Stop phase (and even after switching off and then again switching on the
power supply) the overheating signal is still back-lit. This enables the user to establish the cause
of switching off the furnace
.
In order to clear the overheating signal and return to the normal operation, wait until the furnace is cooled
off (switching off the fan) and press the button placed on the housing of the bimetallic sensor. Then, press
the Start button, which will cause the lighting of the diode signalling overheating to be switched off. The
furnace may be restarted.
The overflow signal is generated by a mechanical sensor placed under the overflow tank. The opening of
the contacts signals overfilling the tank. At the same time, the pump is switched on – the pump operation
indicator is not back-lit anymore (yellow diode) and instead, the relevant red diode signifying the
overfilling is back-lit. The air exhaust fan operates until the furnace temperature below drops below 35°C.
After reaching the temperature lower than 35°C, the furnace returns to the Stop phase. Empty the
overflow tank, and press the Start button, which will cause the (red) diode, which signals overfilling, to
be switched off. The furnace may be restarted..
Fig.5. Placement of elements protecting the heater:
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