Carrier Aquasnap 30RQ User Manual

Procedure for controlling the pressure di󰀨erential setpoint
Once the circuit is cleaned, place the hydraulic circuit in the
conguration for which the unit selection was performed (generally,
this will be all valves open and all cooling coils active)
Read the ow rate on the user interface and compare the value
obtained with the theoretical value of the selection:
■ If the ow rate read is greater than the preset value, reduce the
pressure di󰀨erential setpoint on the user interface to reduce
the ow rate value;
■ If the ow rate read is lower than the preset value, increase the
pressure di󰀨erential setpoint on the user interface to increase
the ow rate value
Repeat until the unit's nominal ow rate at the required operation
point is achieved.
Stop the forced operation of the pump and proceed to the
conguration of the unit for the required control mode. Modify the
control parameters:
■ Set the water ow rate control to “pressure di󰀨erential”
■ Set the value of the required pressure di󰀨erential.
The unit's default factory conguration is the minimum speed
(frequency: 30 Hz).
NOTE:
If during adjustment, the low or high frequency limits are
reached before reaching the specied ow rate, keep the
pressure di󰀨erential value at its lower or higher limit as the
control parameter value.
If the user knows in advance the pressure di󰀨erential value
at the unit outlet to be maintained, this value can be entered
directly as a parameter to be declared. You should not,
however, omit the hydraulic circuit cleaning sequence
9.4 - Units with hydraulic module and variable-
speed pump – Temperature di󰀨erential control
The installation ow rate has not been set to a rated value.
The ow rate will be adjusted, by varying the pump speed,
to maintain a heat exchanger temperature di󰀨erential value dened
by the user.
This is checked by the temperature sensors at the water exchanger
inlet and outlet (items 8 and 9 on the typical hydraulic circuit
diagram).
The system reads the measured temperature values, calculates
the corresponding Delta T°, compares it with the setpoint value
set by the user and then modulates the pump speed accordingly.
■ This results in an increase in the ow rate if the Delta T° exceeds
the setpoint.
■ This results in a decrease in the ow rate if the Delta T° is less
than the setpoint.
This variation in ow rate is limited by the maximum and minimum
permissible ow rate values for the unit and by the maximum and
minimum pump supply frequency values.
The maintained Delta T° may, in certain cases, di󰀨er from the
setpoint value:
■ If the setpoint value is too high (corresponding to a ow rate
lower than the minimum value or a frequency less than the
minimum value), the system will be limited to the minimum ow
rate or minimum frequency, which will result in a
Delta T below the setpoint,
■ If the setpoint value is too low (corresponding to a ow rate
higher than the maximum value or a frequency greater than
the maximum value), the system will be limited to the maximum
ow rate or maximum frequency, which will result in a Delta T
above the setpoint.
Contact the manufacturer's Service to implement the procedures
described below.
Hydraulic circuit cleaning procedure
Refer to the hydraulic circuit cleaning procedure.
Procedure for adjusting the Delta T° setpoint
Once the circuit is cleaned, stop the forced start of the pump and
proceed to the conguration of the unit for the required control
mode.
Modify the control parameters:
■ Water ow rate control method (temperature di󰀨erential)
■ Set the required Delta T.
The unit's default factory conguration is the minimum speed
(frequency: 30 Hz).
9.5 - Units with hydraulic module and variable-
speed pump - Setting a xed ow rate for the
system
The ow will be set to a nominal value. This value will remain
constant, and will not be dependent on variations in the
installation's load.
Contact the manufacturer's service department to implement the
procedures described below
Hydraulic circuit cleaning procedure
Refer to the hydraulic circuit cleaning procedure.
Procedure for controlling the ow rate
Once the circuit has been cleaned, set the required water ow
rate by adjusting the pump frequency on the user interface.
Stop the forced operation of the pump and proceed to
the conguration of the unit for the required control mode. Modify
the control parameters:
■ Water ow rate control method (xed speed)
■ Constant frequency value.
The unit's default factory conguration is the minimum speed
(frequency: 30 Hz).
9 - NOMINAL SYSTEM WATER FLOW RATE CONTROL
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Carrier Aquasnap 30RQ Specifications

General

Brand	Carrier
Model	Aquasnap 30RQ
Category	Chiller
Language	English