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Water Piping
Water Pumps
Avoid the use of 3600/3000-rpm (two-pole motor) pump motors. It is not uncommon to find
that these pumps operate with objectionable noise and vibration.
It is also possible to build up a frequency beat due to the slight difference in the operating rpm
of the pump motor and the Daikin centrifugal motor. Daikin encourages the use of 1750/1460
rpm (four-pole) pump motors.
Vessel Drains at Start-up
Unit vessels are drained of water in the factory and are shipped with the drain plugs in the
heads removed and stored in the control panel or with open ball valves in the drain hole. Be
sure to replace plugs or close the valves prior to filling the vessel with fluid.
Evaporator and Condenser Water Piping
All evaporators and condensers come standard with Victaulic
AWWA C-606 groove nozzles (also suitable for welding), or
optional flange connections.
The installing contractor must
provide matching mechanical connections or transitions of the
size and type required. A heat recovery chiller, DHSC, (shown
on the right) has two sets of condenser piping; one for the tower,
one for the heating system.
The tower connections are always the inboard pair of
connections. In the figure to the right, the condenser connections
are "left-hand" when viewed from the front of the unit (Unit
Control Panel and Interface Panel side), so in this case, the right-
hand condenser connections would be for the tower.
If the condenser connections were on the other end ("right-
hand"), the tower connections would be the left-hand pair of
Important Note on Welding
If welding is to be performed on the mechanical or flange connections, remove the solid-state
temperature sensor and thermostat bulbs from the wells to prevent damage to those
components. Also properly ground the unit or severe damage to the MicroTech II unit
controller can occur.
Water pressure gauge connection taps and gauges must be provided in the field piping at the
inlet and outlet connections of both vessels for measuring the water pressure drops. The
pressure drops and flow rates for the various evaporators and condensers are job specific and
the original job documentation can be consulted for this information. Refer to the nameplate
on the vessel shell for identification.
Be sure that water inlet and outlet connections match certified drawings and stenciled nozzle
markings. The condenser is connected with the coolest water entering at the bottom to
maximize subcooling.
Note: When common piping is used for both heating and cooling modes, care must
be taken to provide that water flowing through the evaporator cannot exceed 110°F
which can cause the relief valve to discharge refrigerant or damage controls.
The piping must be supported to eliminate weight and strain on the fittings and connections.
Piping must also be adequately insulated.
A cleanable 20-mesh water strainer must be
D-EIMWC00804-14EN
Centrifugal Chillers
15
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