United Technologies Carrier 30RQM 160, Инструкции по установке, эксплуатации и обслуживанию

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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.
Example: Unit with
specified nominal flow rate of 10.6 l/s
Water flow rate, l/s
Pressure
drop,
kPa
Legend
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.
8.3.2 - Procedure for controlling the pressure
differential setpoint
Once the circuit has been decontaminated, place the water circuit
in the configuration chosen when the unit was selected (in general,
all valves open and all transmitters in on-state).
Read the value of the flow on the user interface and compare it
with the theoretical value of the range:
-
If the value read is greater than the specified value, reduce
the pressure differential setpoint on the user interface to
reduce the flow value;
-
If the value of the flow is lower to the specified value, increase
the pressure differential setpoint on the user interface to
increase the value of the flow.
Repeat until the unit's design flow rate is achieved.
Stop the forced operation of the pump and proceed to the
configuration of the unit for the required control mode. Modify the
control parameters:
-
Set water flow control to ‘pressure differential’
-
Set the value of the required pressure differential.
By default, the unit is configured at the minimum speed (frequency:
30 Hz).
NOTE:
If during adjustment, the low or high frequency limits are
reached before reaching the specified flow rate, keep the
pressure differential value at its lower or higher limit as the
control parameter value.
If the user already knows the pressure differential value to
be maintained at the unit outlet, this may be entered directly
as a parameter. The decontamination sequence for the water
circuit must not be used.
8.4 - Units with hydraulic module and variable
speed pump – Temperature differential control
The installation flow rate is not set at a nominal value.
The flow rate will be adjusted, by varying the pump speed, to
maintain a heat exchanger temperature 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.
8.4.1 - Cleaning procedure for the water circuit
Refer to the cleaning procedure for the water circuit in section
8.3.1.
8.4.2 - Procedure for controlling the Delta T° setpoint
Once the circuit is cleaned, stop the forced start of the pump and
proceed to the configuration of the unit for the required control
mode.
Modify the control parameters:
-
Set water flow control to ‘temperature differential’
-
Set the value of the required differential temperature.
By default, the unit is configured at the minimum speed (frequency:
30 Hz).
8 - NOMINAL SYSTEM WATER FLOW CONTROL
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