Grundfos ALPHA+ 15-40, Installation And Operating Instructions Manual

Page: 10 / 272

10
6.3 Automatic night-time duty
To ensure correct function of the automatic
night-time duty, these conditions
must be ful-
filled:
• The pump must be installed in the flow pipe.
• The system must be fitted with a flow tem-
perature sensor and a device for automatic
control of the changeover between normal
duty and automatic night-time duty.
To activate the automatic night-time duty, turn
the selector switch on the terminal box to posi-
tion ,
see
u
.
(Pos. 1 = automatic night-time duty, pos. 2 =
normal duty.)
Note: If the heating system is undersupplied
(heat capacity too low), check whether auto-
matic night-time duty has been activated. If yes,
deactivate the function.
Once automatic night-time duty has been acti-
vated, the pump changes automatically be-
tween normal duty and night-time duty, see
v
.
(Pos. 1 = normal duty, pos. 2 = without auto-
matic night-time duty, pos. 3 = with automatic
night-time duty.)
Changeover between normal duty and night-
time duty is dependent on the flow-pipe temper-
ature.
The pump automatically changes over to night-
time duty when the built-in sensor registers a
flow-pipe temperature drop of more than
10-15°C within approx. 2 hours. The tempera-
ture drop must be at least 0.1°C/min.
Changeover to normal duty takes place without
a time lag when the temperature has increased
by approx. 10°C.
Pumps incorporated in gas boilers
with small water content must never
be set to automatic night-time duty.