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8.2 - Units with hydraulic module and fixed speed
pump
8.2.1 - General information
See chapter 8.1.1 ''Units without hydraulic module''
8.2.2 - Cleaning procedure for the water circuit
•
Open the valve completely (item 19).
•
Start up the unit's pump.
•
Read the flow value on the user interface.
•
Let the pump run for 2 hours continuously to clean up the
system's hydraulic circuit (presence of contaminating solids).
•
Perform another reading of the flow and compare this value
with the initial value.
A decrease in the flow 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 16) and
remove the filters (items 17 and 1) after draining the hydraulic
part of the unit (item 6).
•
Remove the air from the circuit (items 5 and 14).
•
Repeat until all fouling is removed from the filter.
8.2.3 - Procedure for controlling water flow
Once the circuit is cleaned, read the flow value on the user
interface and compare it to the theoretical selection value.
If the value of the flow is greater than the specified value, this
indicates that the overall pressure drop in the system is too low
compared to the available static pressure generated by the pump.
In this case, close the control valve and read the new flow rate
value.
Repeat as necessary, closing the control valve until the system's
specific pressure drop corresponding to the unit's design flow
rate is achieved.
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 cannot be obtained (lower resulting flow) and the
difference in temperature between the water inlet and outlet of
the water heat exchanger will be increased.
To reduce the system's hydraulic network pressure drop:
•
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.
36
Example: Unit with specified nominal flow rate of 10.6 l/s
Key
1
Unit pump curve
2
Pressure drop in the hydraulic kit (to be measured on the pressure gauge installed on the
water inlet and outlet)
3
Pressure drop in the installation with wide open control valve
4
Pressure drop in the installation after setting the valve to obtain the specified nominal flow rate.
8.3 - Units with hydraulic module and variable speed
pump – Pressure differential control
The installation flow rate is not set at a nominal value.
It will be adjusted by the system, by varying the pump speed, to
maintain a constant available pressure differential value defined
by the user. 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.
Contact Carrier Service to discuss the implementation of the
procedures set out below.
8.3.1 - Cleaning procedure for the water circuit
Before proceeding, it is advisable to remove any possible
contamination from the hydraulic circuit.
•
Start up the unit pump by using the forced start command.
•
Control the frequency to the maximum value to generate
a higher flow.
•
If there is a ''Maximum flow exceeded'' alarm, reduce the
frequency until an acceptable value is reached.
•
Read the value of the flow on the user interface.
•
Let the pump run for 2 hours continuously to clean up the
system's hydraulic circuit (presence of contaminating solids).
•
Perform another reading of the flow and compare this value
with the initial value. A decrease in the flow 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 16) and remove the filters (items 17 and 1) after
draining the hydraulic part of the unit (item 6).
•
Remove the air from the circuit (items 5 and 14).
•
Repeat until all fouling is removed from the filter.
Water flow rate, l/s
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