
D-EIMWC01308-16EN - 13/40
eliminator sections in the condenser inlet and outlet water piping. But they can be required where noise
and vibration are critical or if spring isolators are used.
Vessel Drains at Start-up
Unit vessels are equipped with ball-type drain valves in the bottom of each head chamber and shipped
with the valves open. Be sure to close the valves prior to filling the vessels with fluid.
Draining Vessels
If the chiller can be subject to freezing temperatures (possibly when stored prior to installation), the
condenser and evaporator must be drained of all water. Dry air blown through them will aid in forcing
all water out. Removal of condenser heads is also recommended. The condenser and evaporator are not
self-draining and tubes must be blown out. Water permitted to remain in the piping and vessels can
rupture these parts if subjected to freezing temperature and cause corrosion.
Evaporator and Condenser Water Piping
Be sure that water inlet and outlet connections match certified drawings and stenciled nozzle markings.
The tower water supply connection is always the bottom connection of the condenser to maximize
refrigerant sub cooling.
All evaporators and condensers come with optional flange connections or standard Victaulic groove
water nozzles (also suitable for welding). Since the companion flanges, bolts, nuts and gaskets are not
included, the installing contractor must provide matching mechanical connections or transitions of the
size and type required.
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 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 unit nameplate on the control panel for identification. The
piping should also include thermometers at the inlet and outlet connections and air vents at the high
points.
The piping must be installed and supported to eliminate weight and strain on the fittings and
connections. Cold piping must also be adequately insulated. All water piping should be thoroughly
cleaned of dirt and debris before being connected to the chiller. A cleanable 20-mesh water strainer must
be installed in both water inlet lines as close as possible to the vessels. The strainer will attempt to retain
any possible dirt/debris coming from the cooling tower, deterioration of piping, or from water source
entering the chiller tubes. This can result in a reduction of flow and subsequent reduction of chiller
performance or tube freezing.
Water Flow Sensors
Temperature-based (thermal dispersion) flow sensors are factory mounted in the evaporator and
condenser inlet water nozzles and are factory wired to the control panel. The sensor tip houses
thermistors and a heating element that when power is applied, heats the tip of the probe. How fast the
heat is carried away from the sensor tip by the water flow is detected by the thermistors and they
provide an output when the flow rate falls below the setpoint. This indicates whether there is an
adequate water flow to the vessels before the unit can start. They also serve to shut down the unit in the
event that water flow is interrupted to guard against evaporator freeze-up or excessive discharge
pressure.