Carel pRack pR300T Mode D'emploi page 38

ENG
If selecting pump management based on heat recovery demand, the pump will be activated as soon as the
heat recovery demand activation threshold is reached. The pump will be deactivated, after the set delay, when
reaching the heat recovery demand deactivation threshold. If on the other hand the pump is set as being
activated according to the difference between the heat exchanger water inlet and outlet temperature, the
activation percentage will be calculated using PI control, which compares this difference against the set point.
In relation to set point, this type of control is direct: if the difference between the water inlet and outlet
temperature is greater than the set point, the pump will be activated.
Pump modulating output (%)
100
Parameter Min.speed HR on can be used to specify a minimum operating percentage when heat recovery
is active.
The pump can also be started when heat recovery is not active. The user can specify duty cycles based on an
ON time and an OFF time. During the ON time, the pump will operate at the set percentage (if modulating).
cod. +030220595 - 1.2 - 13.08.2020
Screen Eeab11 can be used to specify:
•
•
•
Set-point
Screen Eeab12 can be used to enable the pump duty cycles
when heat recovery is not active, and the corresponding ON
and OFF times.
If a flow switch is available for measuring water circulation,
this can be connected to the pRack and configured on screen
Eeaa10. If the pump is active and the flow switch measures
no flow, an alarm will be signalled.
the activation set point as a difference in water temperature
the PI control proportional gain
the PI control integral time.
Set-point +100/K
p
Fig. 2.c
12
Temperature
di erential (° C)