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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).
8.5 - Units with hydraulic module and variable speed
pump – Setting a fixed flow for the system
The flow will be set to a nominal value. This value shall remain
constant, and will not be dependent on variations in the
installation's load.
Contact Carrier Service to discuss the implementation of the
procedures set out below.
8.5.1 - Cleaning procedure for the water circuit
Refer to the cleaning procedure for the water circuit in section
8.3.1.
8.5.2 - Procedure for controlling the flow
Once the circuit is cleaned, set the required water flow by
adjusting the pump frequency on the user interface.
Stop the forced operation of the pump and configure the unit
for the required control mode.
Modify the control parameters:
•
Water flow control method (fixed speed).
•
Constant frequency value.
By default, the unit is configured at the minimum speed
(frequency: 30 Hz).
37
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