Daikin WGZ030DW Installation, Operation And Maintenance Manual page 94

Flow Switch Installation and Calibration
A thermal dispersion flow switch uses heat to determine
flow and therefore must be calibrated during system startup.
A thermal dispersion flow switch can be an acceptable
replacement for paddle type flow switches and differential
pressure switches but care must be taken regarding wiring.
The thermal dispersion flow switch supplied by Daikin Applied,
shown in Figure 1, comes as a 2 part unit consisting of a flow
switch and an adapter labeled E40242 by the supplier.
Figure 43: Thermal Dispersion Flow Switch and Adapter
Mounting
Figure 44 highlights the position of the electrical connector and
indentation 'mark' on flow switch.
Figure 44: Flow Switch Details
It is required that the flow switch be mounted such that the
electrical connection and indentation 'mark' are oriented as
recommended in Figure 45. It is important that the flow switch
be mounted so that the probe is sufficiently inserted into the
fluid stream. It may not be mounted directly on top or directly
on the bottom of a horizontal pipe.
If the flow sensor is to be mounted away from the unit, the
sensor should be mounted on the wall of the inlet pipe of
IOM 1322 • WATER-COOLED SCROLL COMPRESSOR
Startup and Shutdown Procedures
evaporator and condenser, or in a run of straight pipe that
allows 5 to 10 pipe diameters prior to the sensor and 3 to 5
pipe diameters of straight pipe after the sensor. Flow switch
is placed in inlet pipe to reflect flow leaving the barrel. If
installation on the outlet pipe is necessary, contact Chiller
Technical Response at TechResponse@DaikinApplied.com to
review the jobsite details.
NOTE: DO NOT alter or relocate factory installed flow
switches. If issues exist, contact Chiller Technical
Response at TechResponse@DaikinApplied.com.
Figure 45: Remote Mounting Guidelines for Flow Switch
If needed, the adapter is threaded into the pipe using pipe
sealant appropriate for the application. The flow sensor is
mounted onto the adapter using silicone grease. Carefully
apply lubricant to the inside threads and o-ring so temperature
probe does not become coated with lubricant. Torque the
adapter/sensor connection to 18.5 ft/lbs.
Wiring
Refer to wiring diagram in the unit control panel.
Either AC or DC is used to power the flow switch. The unit
controller's digital input is a DC signal which is supplied
through the switch output of the flow switch for flow indication.
It is required that the AC and DC commons of power be
separated. Contact Chiller Technical Response for alternate
wiring scenarios.
Flow Switch Setup
The flow switch comes from the factory set at a default velocity
of 20 cm/s. This value is typically well below the minimum
water flow specified for the unit's evaporator and condenser so
field adjustment is required for adequate low flow protection.
"Table 46: Flow Volume Calculation" on page 95
calculated gallons per minute (gpm) for Schedule 40 steel pipe
for various fluid velocities from 20 cm/s to 300 cm/s. The flow
switch has an overall range of adjustment from 3 cm/s to 300
cm/s.
Step 1: Adjust flow through the evaporator to the minimum
desired operating gpm. Maintain this flow throughout the setup
procedure.
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