Water flow rate adjustment procedure
Once the circuit is cleaned, read the flow rate value on the user
interface and compare it to the theoretical selection value.
If the value of the flow rate read is greater than the specified value,
this indicates that the overall pressure drop in the system is too
low against the available static pressure generated by the pump.
In this case, close the control valve (item 22) and read the new
flow rate value.
Repeat by successively closing the control valve (item 22) until
the nominal flow rate is achieved at the unit's required operation
point.
NOTE:
If the network has an excessive pressure drop in relation to
the available static pressure delivered by the unit pump,
the nominal water flow rate cannot be obtained (lower
resulting flow rate) and the difference in temperature between
the water inlet and outlet of the water type heat exchanger
will be increased
To reduce the installation's hydraulic system pressure drop, it is
necessary to:
-
Reduce the pressure drops of individual components (bends,
level changes, options, etc.) as much as possible;
- Use the correct pipe diameter;
- Do not extend the hydraulic systems
Example: unit with specified nominal flow rate of 10.6 l/s
Pressure
drop,
kPa
Water flow rate, l/s
Key
B
Unit pump curve
C
Pressure drop in the hydraulic module (to be measured on the pressure gauge
installed on the water inlet and outlet)
D
Pressure drop in the installation with wide open control valve
E
Pressure drop in the system after setting the valve to obtain the nominal flow
rate specified.
9.3 - Units with hydraulic module and
variable-speed pump – Pressure differential
control
The installation flow rate has not been set to a rated value.
It will be adjusted by the system, by varying the pump speed,
to maintain a constant operating pressure differential value defined
by the user.
This is checked by the pressure sensor at the outlet of the water
type heat exchanger (item 10 on the typical hydraulic circuit
diagram).
The system calculates the measured pressure difference,
compares it with the setpoint value set by the user and then
modulates the pump speed module accordingly, resulting in:
-
an increase in the flow rate if the measurement is below the
setpoint,
-
a decrease in the flow rate if the measurement exceeds the
setpoint.
This variation in flow rate is limited by the maximum and minimum
permissible flow rate values for the unit and by the maximum and
minimum pump supply frequency values.
The maintained pressure difference value may, in certain cases,
differ from the setpoint value:
-
if the setpoint value is too high (obtained for a flow rate higher
than the maximum value or a frequency greater than the
maximum value), the system will stop once it reaches the
maximum flow rate or maximum frequency, which will result in
a pressure difference below the setpoint,
-
if the setpoint value is too low (obtained for a flow rate lower
than the minimum value or a frequency less than the minimum
value), the system will stop once it reaches the minimum flow
rate or minimum frequency, which will result in a pressure
difference greater than the setpoint.
Contact the manufacturer's service department to implement the
procedures described below
Hydraulic circuit cleaning procedure
Before proceeding, it is advisable to remove any possible
contamination from the hydraulic circuit.
- Start up the unit pump using the override command.
- Set the frequency to the maximum value to generate a high
flow rate.
-
If there is a “Maximum flow exceeded” alarm, reduce the
frequency until an acceptable value is reached.
-
Read the flow rate on the user interface.
-
Let the pump run for 2 hours continuously to flush the system's
hydraulic circuit (presence of contaminating solids).
-
Perform another reading of the flow rate and compare this value
with the initial value. A decrease in the flow rate value indicates
that the filters in the system need to be removed and cleaned.
In this case, close the shut-off valves on the water inlet and
outlet (item 19) and remove the filters (items 20 and 1) after
draining the hydraulic part of the unit (items 6).
- Remove the air from the circuit (items 5 and 17).
-
Repeat until all fouling is removed from the filter
9 - NOMINAL SYSTEM WATER FLOW RATE CONTROL
EN-39
AQUACIAT
POWER
™ LD/ILD
Summary of Contents for AQUACIAT POWER LD 1100R
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