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5.4
0311720_SUF_120-500_III_UKUK_V2.0 , 2017-08-01
Operating cycle
The temperature sensor T
heater (T
). This temperature is sent to the controller. As soon as T
top
set water temperature (T
set
running and the gas control valve (16) is opened. The fan runs at full speed and the gas is
mixed with the air in the venturi (30). This mixture is ignited by the hot surface igniter
(20) and the water becomes heated. As soon as the water temperature approaches T
the fan rpm drops to the partial load speed (this is also referred to as modulating). Once
T
rises above T
, the heat demand ends and the controller stops the operating cycle.
1
set
When responding to both the start and end of the heat demand, the controller assumes a
certain margin. We refer to this margin as the hysteresis (see section 9.2.1).
(7) measures the water temperature at the top of the water
1
), the controller registers a "heat demand". The fan (18) starts
is lower than the
1
set
45
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