Setting The Pump; Pump Setting For System Type; Pump Control - Grundfos ALPHA1 Series Installation And Operating Instructions Manual

8. Setting the pump

8.1 Pump setting for system type

A
B
C
D
Fig. 10 Selection of pump setting for system type
Factory setting = highest proportional-pressure curve (PP2).
Recommended and alternative pump settings according to fig. 10:
Pos. System type
A Underfloor heating
B Two-pipe systems
C One-pipe systems
D Domestic water
* See section 14.1 Guide to performance curves.
Changing from recommended to alternative pump setting
Heating systems are "slow" systems that cannot be set to the
optimum operation within minutes or hours.
If the recommended pump setting does not give the desired
distribution of heat in the rooms of the house, change the pump
setting to the shown alternative.
Explanation to pump settings in relation to performance curves,
see section 11. Pump settings and pump performance.
18
Recommended
Lowest constant-pressure curve (CP1)*
Highest proportional-pressure curve (PP2)*
Lowest proportional-pressure curve (PP1)*
Constant speed, speed I*

8.2 Pump control

During operation, the pump head will be controlled according to
the principle "proportional-pressure control" (PP) or "constant-
pressure control" (CP).
In these control modes, the pump performance and consequently
the power consumption are adjusted according to the heat
demand in the system.
Proportional-pressure control
In this control mode, the differential pressure across the pump is
controlled according to the flow.
The proportional-pressure curves are indicated by
in the Q/H diagrams. See section 11. Pump settings and pump
performance.
Constant-pressure control
In this control mode, a constant differential pressure across the
pump is maintained, irrespective of the flow.
The constant-pressure curves are indicated by
are the horizontal performance curves in the Q/H diagrams.
See section 11. Pump settings and pump performance.
III II I POWER III III II II
III II I POWER III III II II
III II I POWER III III II II
III II I POWER III III II II
Pump setting
Alternative
Highest constant-pressure curve (CP2)*
Lowest proportional-pressure curve (PP1)*
Highest proportional-pressure curve (PP2)*
Constant speed, speed II or III*
I I POWER POWER
( OK )
I I POWER POWER OWER O R
( OK )
I I POWER POWER
( OK )
I I POWER POWER ER
( OK )
PP1 and PP2
CP1 and CP2 and