DORCHESTER DR-FC 120, Installation, Comissioning And Maintenance Instructions

Page: 56 / 100

Starting the water heater
54 Instruction manual DR-FC
9
gis
When the water heater starts, it will run through the
following steps:
1. The water temperature drops below the set
temperature of (for example)
65
°C. The controller
detects a heat demand and starts the operating
cycle.
-
The icon is activated.
- The message
HEAT DEMAND
appears.
2. Once demand is registered, the fan is started to
exhaust any gases that may be present. This
phase is called pre-purge and lasts about 15
seconds.
-
The icon is activated.
- The message
PRE PURGE
appears.
3. During the pre-purge, the pressure switch closes.
- The icon is activated.
- The message
PRESSURE SWITCH
appears.
4. This is then followed by the (pre-)glow of the hot
surface igniter.
-
The icons and are dimmed
- The icon is activated.
5. After a number of seconds pre-glow, the gas
control valve is opened and ignition takes place.
-
The icon is activated.
- The message
IGNITION
appears.
6. After ignition, the flame is detected and the water
heater will be running. This means that actual
heating has started:
-
The icon is dimmed.
- The icon is activated.
- The message
RUNNING
appears.
7. When the water is up to temperature, the heat
demand drops off and the post-purge starts. This
lasts about 25 seconds.
-
The icons , and are dimmed.
- The icon is activated.
- The message
POST PURGE
appears.
8. Following the post-purge, the fan stops and the
pressure switch opens:
-
The icons and are dimmed.
- The message
POST PURGE
vanishes.
With any subsequent heat demand, the operating
cycle will resume from step 1.
ON Ê
13:45 Thursday 63ÉC
Tset 65ÉC
HEAT DEMAND
ON Ê Ê
13:45 Thursday 63ÉC
Tset 65ÉC
PRE PURGE
ON Ê Ê Ê
13:45 Thursday 63ÉC
Tset 65ÉC
PRESSURE SWITCH
ON Ê Ê
13:45 Thursday 63ÉC
Tset 65ÉC
GLOW PLUG
a
a
a
a
ON Ê Ê Ê
13:45 Thursday 63ÉC
Tset 65ÉC
IGNITION
ON Ê Ê Ê
13:45 Thursday 63ÉC
Tset 65ÉC
RUNNING
ON Ê Ê
13:45 Thursday 65ÉC
Tset 65ÉC
POST PURGE
ON
14:05 Thursday 65ÉC
a
a
a
a