E93.1001EN.C Manual CD
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By pressing the [SERVICE] button of the water heater, the water heater can be started without a heating demand.
The water heater will start to fire and also the pump will start to run. Firing of the water heater without a water flow
(but filled with water) will cause the so called “boiling noises”. Check during this “service function” operation also
the flow and return temperatures of the water heater
by pressing the [◄] button once. The temperature difference
of the flow and return must be at least 13°C and maximum 25°C. This temperature difference indicates that there
is (enough) water flow over the water heater; this water flow prevents the heat exchanger of possible damage
caused by a thermal overload.
Flow monitoring
Another safety feature of the water heater, to make sure that there is enough water flow over the water heater, is
the monitoring of the flow and return temperatures (T2 and T1). When the temperature difference (delta T) between
flow and return exceeds a certain (set) value (load dependent), the following warning messages will be shown in
the display.
Display message
T 2
- T 1
h
i
g h
9 9 9
,
5
h r s
Reason
Temperature difference T2-T1 has exceeded the blocking value, as set in the pa-
rameters.
Display message
d T
D i
r e c
t
b
l
o c k
9 9 9
,
5
h r s
Reason
The temperature difference between flow and return has exceeded the blocking
value
When this temperature difference exceeds the lock-out setting, the water heater will switch off and the following
lock out code will be shown at the display.
Display message
F16
F
l
o w R e
t u r n
d T
f
a u
l
t
p u m p
o n
9 9 9
,
5
h r s
Reason
Temperature difference between flow and return exceeds limitation value,
or 'dT Direct block' has occurred three times.
When these messages appear and/or the water heater will lock out, it means that there is not enough flow over
the water heater. In this case check the functioning of the pump.
The water heater has a built in water pressure switch. If water pressure of the system drops under a certain limit,
the water heater will go in a lock-out.
During and after the commissioning of the water heater, the operation of the water heater pump must be checked,
before leaving the installation room.
NOTICE: Always check the running of the pump before firing the water heater.
