Table of Contents
Advertisement
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 a (enough) water flow over the water heater; this water flow prevents the heat exchanger of possible damage caused by a thermal
overload.
18.4
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
Reason
Temperature difference T2-T1 has exceeded the blocking value, as set in the parameters
P2CO, P2CR until P2CV.
Display message
Reason
Temperature difference T2-T1 has exceeded the blocking value, as set in the parameters.
When this T2-T1 value 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
Reason
Temperature difference T2-T1 has exceeded the blocking value, or after three times Delta
Direct block.
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.
T
2
-
T
1
h
D
e
l
t
a
D
F
l
o
w
R
e
t
p
u
m
p
o
n
i
g
h
9
9
9
i
r
e
c
t
b
9
9
9
u
r
n
d
t
9
9
9
,
5
h
r
s
l
o
c
k
,
5
h
r
s
f
a
u
l
t
,
5
h
r
s
88
Advertisement
Table of Contents
