Daikin WGZ030DW - Flow Switch and Glycol Solutions

www.DaikinApplied.com 11 IOM 1322 • WATER-COOLED SCROLL COMPRESSOR
to desired ow. Do not reduce ow lower than the part load
minimum ows listed on page 18 or page 19.

A water ow switch must be mounted in the leaving evaporator
and condenser water lines to prove adequate water ow
before the unit can start. This will safeguard against slugging
the compressors on start-up. It also serves to shut down the
unit in the event that water ow is interrupted to guard against
evaporator freeze-up. There are two options for meeting this
requirement.
1. A factory-mounted thermal dispersion ow switch.
2. A “paddle” type ow switch is available from Daikin
Applied (part number 017503300) for eld mounting
and wiring. Wire from switch terminals Y and R to the
unit control panel terminals shown on the eld wiring
diagrams, page 42 and page 43. Mount the ow
switch in the leaving water line to shut down the unit
when water ow is interrupted. A ow switch is an
equipment protection control and should never be used
to cycle a unit.
Installation should be per manufacturer’s instructions included
with the switch. There is also a set of normally closed contacts
on the switch that can be used for an indicator light or an alarm
to indicate when a “no ow” condition exists. Flow switches
should be calibrated to shut o󰀨 the unit when operated below
the minimum listed ow rate for the unit listed on page 18.
Provide freeze/condensation protection for any ow switch that
is installed outdoors. Di󰀨erential pressure switches are not
recommended. They can freeze and fail to indicate a no-ow
condition.
On units with factory-mounted ow switches and where ange
connections (grooved-to-ange adaptors or weld-on anges)
are to be used, relocating the ow switch is required to allow
for possible future replacement since the ange will interfere
with unscrewing the switch. The following is recommended,
before installing a ange, to avoid interference
1. Remove the ow switch before and plug the switch
opening in the nozzle.
2. Install the grooved-to-ange adaptor or weld on ange.
3. Relocate the ow switch in the water piping outside the
ange, close enough to it that the wire leads will reach
and the switch can still be unscrewed.
NOTE: A water ow switch must be mounted in the
evaporator outlet water line to signal that there is
water ow before unit will start.

CAUTION
Do not use automotive antifreeze. Industrial glycols must be used.
Automotive antifreeze contains inhibitors that causes plating on copper
tubes. The type and handling of glycol used must be consistent with local
codes.
WGZ units are designed to operate with a leaving chilled
uid temperature from 15°F (-9.4°C) to 60°F (16°C). Leaving
chilled uid temperatures below 40°F (4.6°C) result in suction
temperatures at or below the freezing point of water and a
glycol anti-freeze solution is required. When glycol is added
to the chilled water system for freeze protection, recognize
that the refrigerant suction pressure will be lower, cooling
performance less, and water side pressure drop will be
higher. The reduction in performance depends upon the glycol
concentration and temperature. This should be taken into
consideration during initial system design.
Daikin Applied recommends a minimum concentration of 25%
be provided on all glycol applications. Glycol concentrations
below 25% are too diluted for long-term corrosion protection of
ferrous metals and corrosion inhibitors need to be recalculated
and possibly added to the system.Glycol concentrations
greater than 35% are not recommended due to the higher
pressure drops and losses of capacity and e󰀩ciency. Glycol
concentrations higher than 35% do not o󰀨er any additional
burst protection.
When glycol is required in the chilled water system, reset the
freezestat and low leaving water alarm temperatures. The
freezestat is factory set to default at 36°F (2.2°C). Reset the
freezestat setting to approximately 4° to 5°F (2.3° to 2.8°C)
below the leaving chilled water setpoint temperature.
Glycol in the condenser will have a negligible e󰀨ect on
performance because glycol at these higher temperatures will
perform with characteristics similar to water.
