Starting up and shutting down
50
Instruction manual DR-LA
7
gis
7.4
Heating cycle
The heating cycle is activated as soon as the measured water temperature
(T
water
) falls below the threshold value (T
set
). This threshold value depends on
the state in which you want to place the water heater. For example, if the water
heater is in the "OFF mode" (frost protection), then this value is 20°C. If the
water heater is in the "ON mode", then this threshold value is selectable, for
example, position 3 (60°C).
The heating cycle runs in turn through the following states:
1. HEAT DEMAND;
2. WAITING TIME;
3. PRE-GLOW;
4. IGNITION;
5. RUNNING;
6. WAITING TIME.
The complete cycle is explained in the example set out below.
n
Caution
The water heater runs through an identical cycle when frost protection is
activated.
1. The control thermostat sensor measures the water temperature. The water
temperature falls below the set temperature, e.g. 60°C, causing the control
thermostat to close. The burner control now detects a heat demand and
starts the heating cycle.
2. After heat demand is detected, the waiting time begins. This waiting time
ensures the ignition takes place safely. The waiting time lasts about 15
seconds.
3. Once the waiting time is over (audible ’clicking’ of the relay in the burner
control) the pre-glowing of the hot surface igniter is started
4. After about 12 seconds (pre-)glowing, the gas control is opened and ignition
can take place.
5. After ignition, the flame is detected and the water heater will be running. This
means that actual heating has started.
6. When the water is up to temperature, the heat demand cuts out. The gas
control closes and the burner tray is extinguished. A new waiting time
begins, of about 10 seconds.
7. After this waiting time, the water heater enters a state of rest and waits until
the water temperature again falls below the set temperature.
With any subsequent heat demand, the heating cycle will resume from step 1.
