DORCHESTER DR-FC 25, Installation, Commissioning And Maintenance Instructions

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The water heater’s heating cycle
Instruction Manual DR-FC 53
gis
5. Turn the appliance OFF (position 0) using the ON/OFF switch on the
control panel. See Figure 7.7 .
6. Disconnect the appliance by putting the mains switch between the appliance
and the mains power supply to position 0.
7.3.3 Shut the water heater down for a longer period
Drain the water heater, if you are shutting it down for a longer period of time.
Proceed as follows:
1. Isolate the water heater from the power supply as described in
paragraph 7.3.2 .
2. Shut off the gas supply.
3. Close the stop valve in the hot water pipe.
4. Open the drain valve.
5. Vent the water heater (or installation) so that it drains completely empty.
7.4 The water heater’s
heating cycle
The water heater’s heating cycle is activated as soon as the measured water
temperature (T
net
) falls below the threshold value (T
set
). This threshold value
depends on the currently selected water heater operating mode. For example,
if the water heater is in the “OFF mode” (frost protection), then this value is 5°C.
If the water heater is in the “ON mode”, then this threshold value is selectable,
for example, 65°C.
The heating cycle runs in turn through the following states:
1. HEAT DEMAND;
2. PRE-PURGE;
3. PRESSURE SWITCH;
4. PRE-GLOW;
5. IGNITION;
6. RUNNING;
7. POST-PURGE.
The complete cycle is explained in the example set out below assuming the
water heater is operating in mode
ON
.
n Remark
The same heating cycle applies to the other operating modes.
Once the water heater starts, it will run through 8 steps:
Figure 7.7 control panel