Daikin WGZ200DW - Flow Switch Installation and Calibration; Flow Switch Setup

IOM 1322 • WATER-COOLED SCROLL COMPRESSOR 94 www.DaikinApplied.com
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A thermal dispersion ow switch uses heat to determine
ow and therefore must be calibrated during system startup.
A thermal dispersion ow switch can be an acceptable
replacement for paddle type ow switches and di󰀨erential
pressure switches but care must be taken regarding wiring.
The thermal dispersion ow switch supplied by Daikin Applied,
shown in Figure 1, comes as a 2 part unit consisting of a ow
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 ow switch.
Figure 44: Flow Switch Details
It is required that the ow switch be mounted such that the
electrical connection and indentation ‘mark’ are oriented as
recommended in Figure 45. It is important that the ow switch
be mounted so that the probe is su󰀩ciently inserted into the
uid stream. It may not be mounted directly on top or directly
on the bottom of a horizontal pipe.
If the ow sensor is to be mounted away from the unit, the
sensor should be mounted on the wall of the inlet pipe of
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 reect ow 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 ow
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 ow 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 ow switch. The unit
controller’s digital input is a DC signal which is supplied
through the switch output of the ow switch for ow 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 ow switch comes from the factory set at a default velocity
of 20 cm/s. This value is typically well below the minimum
water ow specied for the unit’s evaporator and condenser so
eld adjustment is required for adequate low ow protection.
“Table 46: Flow Volume Calculation” on page 95 are the
calculated gallons per minute (gpm) for Schedule 40 steel pipe
for various uid velocities from 20 cm/s to 300 cm/s. The ow
switch has an overall range of adjustment from 3 cm/s to 300
cm/s.
Step 1: Adjust ow through the evaporator to the minimum
desired operating gpm. Maintain this ow throughout the setup
procedure.
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