Daikin EWWQ-AJYNN Service Manual page 9

ESIE 07-05
Water piping
3 Manual or automatic air vent valves at the high points of the system. Drains at the low parts in the
4 Some means of maintaining adequate system water pressure (e.g., expansion tank or regulating
5 Water temperature and pressure indicators located at the unit to aid in unit servicing.
6 A strainer or some means of removing foreign matter from the water before it enters the pump. The
7 A strainer should also be placed in the supply water line just prior to the inlet of the evaporator. This
8 The shell-and-tube evaporator has a thermostat and heating cable to prevent freeze-up down to
9 If the unit is used as a replacement chiller on a previously existing piping system, the system should
10 In the event glycol is added to the water system, as an afterthought for freeze protection, recognize
Prior to insulating the piping and filling the system, a preliminary leak check should be made.
Chilled water The EWWQ-AJYNN water-cooled chiller is equipped with the MicroTech II leaving water controller. Be
thermostat careful when working around the unit to avoid damaging lead wires and sensor cables. Check lead
wires before running the unit. Avoid rubbing the lead wires on the frame or other components. Verify
the lead wires are firmly anchored. If the sensor is removed from the well for servicing, do not wipe off
the heat conducting compound supplied in the well.
Refrigerant charge All units are designed for use with HFC-410A and are shipped with a full operating charge. The
operating charge for each unit is shown in the Physical Data Table.
Flow switch A water flow switch must be mounted in either the entering or leaving water line to insure that there
will be adequate water flow to the evaporator 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 flow
is interrupted to guard against evaporator freeze-up.
Glycol solutions Use industrial grade glycols only. Do not use an automotive grade antifreeze. Automotive antifreeze
contains inhibitors that will cause plating on the copper tubes within the chiller evaporator. The type
and handling of glycol used must be consistent with local codes.
Due to the variety of piping practices, it is advisable to follow the recommendations of local authorities.
They can supply the installer with the proper building and safety codes required for a safe and proper
installation.
Basically, the piping should be designed with a minimum number of bends and changes in elevation
to keep system cost down and performance up. It should contain:
1 Vibration eliminators to reduce vibration and noise transmission to the building.
2 Shutoff valves to isolate the unit from the piping system during unit servicing.
system. The evaporator should not be the highest point in the piping system.
valve).
strainer should be placed far enough upstream to prevent cavitation at the pump inlet (consult
pump manufacturer for recommendations). The use of a strainer will prolong pump life and help
maintain high system performance levels.
will aid in preventing foreign material from entering and decreasing the performance of the
evaporator.
-28°C. Any water piping to the unit must also be protected to prevent freezing.
be thoroughly flushed prior to unit installation and then regular chilled water analysis and chemical
water treatment is recommended immediately at equipment start-up.
that the refrigerant suction pressure will be lower, cooling performance less, and water side
pressure drop greater. System safety devices such as freeze protection and low pressure
protection must be reset.
Introduction
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