Daikin EWAD TZ, Installation, Operation And Maintenance Manual

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–EIMAC00907–16EN - 12/20
Evaporator
and recovery exchangers anti-freeze
protection
All evaporators are supplied with a thermostatically controlled
anti-freeze electrical resistance, which provides adequate anti-
freeze protection at temperatures as low as
–25°C.
However, unless the heat exchangers are completely empty
and cleaned with anti-freeze solution, additional methods
should also be used against freezing.
Two or more of below protection methods should be
considered when designing the system as a whole:

Continuous water flow circulation inside piping and
exchangers

Addition of an appropriate amount of glycol inside the
water circuit

Additional heat insulation and heating of exposed piping

Emptying and cleaning of the heat exchanger during the
winter season
It is the responsibility of the installer and/or of local
maintenance personnel to ensure that described anti-freeze
methods are used. Make sure that appropriate anti-freeze
protection is maintained at all times. Failing to follow the
instructions above could result in unit damage. Damage
caused by freezing is not covered by the warranty.
Installing the flow switch
To ensure sufficient water flow through the evaporator, it is
essential that a flow switch be installed on the water circuit.
The flow switch can be installed either on the inlet or outlet
water piping. The purpose of the flow switch is to stop the unit
in the event of interrupted water flow, thus protecting the
evaporator from freezing.
The manufacturer offers, as optional, a flow switch that has
been selected for this purpose.
This paddle-type flow switch is suitable for heavy-duty outdoor
applications (IP67) and pipe diameters in the range of 1” to 6”.
The flow switch is provided with a clean contact which must be
electrically connected to terminals shown in the wiring
diagram.
Flow switch has to be tune to intervene when the evaporator
water flow is lower than 50% of nominal flow rate.
Heat recovery
Units may be optionally equipped with heat recovery system.
This system in made by a water cooled heat exchanger
located on the compressors discharge pipe and a dedicated
management of condensing pressure.
To guarantee compressor operation within its envelope, units
with heat recovery cannot operate with water temperature of
the heat recovery water lower than 28°C.
It is a responsibility of plant designer and chiller installer to
guarantee the respect of this value (e.g. using recirculating
bypass valve)
Figure 6 - Water piping connection for evaporator
1. Pressure Gauge
2. Flexible connector
3. Flow switch
4. Temperature probe
5. Isolation Valve
6. Pump
7. Filter
Figure 7 - Water piping connection for heat recovery exchangers
1. Pressure Gauge
2. Flexible connector
3. Temperature probe
4. Isolation Valve
5. Pump
6. Filter