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INST
ALLA
TION
COMMISSIONING
7.8 Maximum output in c.h. mode
The maximum useful output in c.h. mode of
model can be varied.
To change the maximum useful output value
in c.h. mode refer to the electronic control/
ignition pcb section of the service manual.
7.9 External temperature probe
setting (optional)
The external temperature probe (if fitted) al-
lows to adjust automatically the temperature
of the c.h. flow with reference to the external
temperature.
The curves given in the chart of Fig. 7.9 rep-
resent the c.h. flow temperature setting as a
function of the external temperature meas-
ured by the external temp. probe.
The relationship between the external tem-
perature and the c.h. flow temperature is
represented by the coefficient K (Fig. 7.9)
that can be set between 0 and 6 as hereaf-
ter explained.
E.g. to obtain a flow temperature setting
of 60°C when the external temperature is
-5°C, K must be set to 1,5 (dashed line in
Fig. 7.9).
Fig. 7.9
20
30
40
50
60
70
80
External temperature °C
C.h. flow temperature °C
20
15
10
5
0
---5 ---10 ---15 ---20 ---25
K=4
K=3
K=2
K=1
K=0,5
K=1,5
K=6
The appropriate value of the coefficient K
depends on the design temperatures of the
c.h. system as the minimum external tem-
perature and the corresponding c.h. flow
temperature.
The coefficient K is factory set to 0 that
is the setting for the operation with no
external temperature probe fitted.
To set the coefficient K:
• Turn on the electricity supply to the boil-
er, switching on the fused spur isolation
switch.
• Set the function knob 7 as illustrated in
Fig. 7.10.
Fig. 7.10
9
8
7
6 5
• Keep pressed the reset button 6 for about
10 seconds until the lock-out signal lamp
5 blinks.
• The lamps should give the indication as in
Fig. 7.11 (coefficient K setting). If not, press
the reset button repeatedly to obtain it.
Where:
Lamp OFF
Lamp ON
Fig. 7.11
• To change the setting turn the knob 8 on
a position corresponding to the desired
coefficient K. By turning the knob 8, the
lock-out signal lamp 5 blinks quickly (2 per
seconds) indicating that the setting has
changed and must be memorised.