Forced Pump Changeover (4.2.4); Pump Test Run (4.2.5); Pump Stop Attempt (4.2.7); Pump Start And Stop Speed (4.2.8) - Grundfos Control DDD Montage- Und Betriebsanleitung

8.7.16 Forced pump changeover (4.2.4)

Fig. 64 Forced pump changeover
Description
The function ensures that the pumps run for the same number of
operating hours.
In certain applications, the requirement remains constant for long
periods and does not require all pumps to run. In such situations,
pump changeover does not take place naturally, and forced pump
changeover may thus be required.
Once every 24 hours, CU 354 checks if any pump running has a
larger number of operating hours than pumps that are stopped. If
this is the case, the pump is stopped and replaced by a pump
with a lower number of operating hours.
Setting range
You can enable and disable the function. You can set the hour of
the day at which the changeover is to take place.
Setting via operating panel
• Settings > Pump cascade control > Forced pump changeover.
1. Select: Enabled.
2. Set: Time of day for changeover.
3. Select interval for pump changeover.
Factory setting
The function is enabled. The time is set to 03:00.
36

8.7.17 Pump test run (4.2.5)

Fig. 65 Pump test run
Description
The function is primarily used in situations where the forced pump
changeover is disabled, and/or if the system is set to operating
mode "Stop", for instance in a period when the system is not
needed. In such situations, it is important to test the pumps
regularly.
Advantages of this function:
• The pumps do not seize up during a long standstill due to
deposits from the pumped liquid.
• The pumped liquid does not decay in the pump.
• Trapped air is removed from the pump.
The pumps start automatically one by one and run for five
seconds.
Pumps in operating mode "Manual" are not included
in the test run. If there is an alarm, the test run will
not be carried out.
Setting range
• Time of day
• Day of week
Setting via operating panel
• Settings > Pump cascade control > Pump test run.
1. Select interval.
2. Set:
• Time of day
– Hours
– Minutes.
3. Select the day of week if you select "Once a week".
Factory setting
The function is disabled.