Control Modes, User Interface And Settings; Pump Control In Heating Systems; Control Mode Explanation - Grundfos Medium UPM Series Data Booklet

Medium UPM

6. Control modes, user interface and settings

Pump control in heating systems

The heating required in a building varies greatly during
the day due to changing outdoor temperatures, solar
radiation and heat emanating from people, electric
appliances, and others. In addition, the need for
heating may vary from one section of the building to
another and the thermostatic valves of some radiators
may have been turned down by the users. An
uncontrolled pump will produce a too high differential
pressure when the heat demand and flow are low.
Possible consequences:
• too high energy consumption
• irregular control of the system
• noise in thermostatic radiator valves and similar
fittings.
Grundfos Medium UPM AUTO pumps automatically
control the differential pressure by adjusting the
performance to the actual heat demand, without the
use of external components.

Control mode explanation

Medium UPM - externally controlled by a
control signal from the system controller
Some Medium UPM pumps are available with external
digital PWM control signal.
PWM A profile (heating) (externally controlled)
The pump runs on constant-speed curves depending
on the current PWM value (regarding VDMA 24244).
The speed decreases when the PWM value increases.
If PWM equals 0, the pump runs at maximum speed.
PWM C profile (solar) (externally controlled)
The pump runs on constant-speed curves depending
on the current PWM value.
The speed increases when the PWM value increases.
If PWM equals 0, the pump stops.
Other external communication signals
Some Medium UPM pumps are available with LIN bus
signal.
Medium UPM AUTO - internally controlled
by the integrated pump controller
Proportional Pressure (internally controlled)
The head (pressure) is reduced with falling heat
demand and increased with rising heat demand.
The duty point of the pump will move up or down on
the selected proportional-pressure curve, depending
on the heat demand in the system.
• PP1: lowest proportional-pressure curve
• PP2: intermediate proportional-pressure curve
• PP3: highest proportional-pressure curve
• AUTO : highest to lowest proportional-
ADAPT
pressure curve.
In Proportional Pressure AUTO
to proportional-pressure control.
The AUTO function enables the pump to control
ADAPT
the pump performance automatically within a defined
performance range.
• Adjusting the pump performance to the size of the
system.
• Adjusting the pump performance to the variations in
load over time.
, the pump is set
ADAPT
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