Water Treatment; Pipework Arrangement; Fig. 5 - Pipework Arrangement - York MILLENNIUM YCAS Installation Operation & Maintenance

The cooler must not be exposed to flushing velocities or
debris released during flushing. It is recommended that
a suitably sized by-pass and valve arrangement is in-
stalled to allow flushing of the pipework system. The
by-pass can be used during maintenance to isolate the
heat exchanger without disrupting flow to other units.
Thermometer and pressure gauge connections should
be provided on the inlet and outlet connections of each
cooler.
Drain and air vent connections should be provided at all
low and high points in the pipework to permit drainage
of the system and to vent any air in the pipes.
Liquid systems at risk of freezing, due to low ambient
temperatures, should be protected using insulation and
heater tape and/or a suitable glycol solution. The liquid
pump(s) must also be used to ensure liquid is circulated
when the ambient temperature approaches freezing point.
Insulation should also be installed around the cooler
nozzles. Heater tape of 21 watts per meter under the
insulation is recommended, supplied independently and
controlled by an ambient temperature thermostat set to
switch on at 21°C (37ºF) above the freezing tempera-
ture of the liquid.
The liquid circulation pump must be controlled by the
unit. This will ensure that when the liquid temperature
falls within 2 or 3°C (3º or 5ºF) of freezing the pump
will start.
The cooler is protected by heater mats under the insula-
tion which are supplied from the unit control system
power supply. During risk of freezing the control sys-
tem should be left switched on to provide the freeze
protection function unless the liquid systems have been
drained.
Any debris left in the water pipework
between the strainer and cooler could
cause serious damage to the tubes in
the cooler and must be avoided. The
installer/user must also ensure that
the quality of the water in circulation
is adequate, without any dissolved
gases which can cause oxidation of
steel parts within the cooler.
YORK INTERNATIONAL

WATER TREATMENT

The unit performance given in the Design Guide is based
on a fouling factor of 0.044m2/hr ºC/kW (0.00025
2
ft hrºF/Btu). Dirt, scale, grease and certain types of
water treatment will adversely affect the heat exchanger
surfaces and therefore unit performance. Foreign mat-
ter in the water system(s) can increase the heat ex-
changer pressure drop, reducing the flow rate and caus-
ing potential damage to the heat exchanger tubes.
Aerated, brackish or salt water is not recommended for
use in the water system(s). YORK recommends that a
water treatment specialist is consulted to determine that
the proposed water composition will not affect the evapo-
rator materials of carbon steel and copper. The pH value
of the water flowing through the cooler must be kept
between 7 and 8.5.

PIPEWORK ARRANGEMENT

The following is a suggested pipework arrangement for
single unit installations. For multiple unit installations,
each unit should be piped as shown.
Isolating Valve - Normally Open
Isolating Valve - Normally Closed
Flow Regulating Valve
Flow Measurement Device
Strainer
Pressure Tapping
Flow Switch
Flanged Connection
Pipework
FIG. 5 – PIPEWORK ARRANGEMENT
FORM 201.18-NM2
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LD03522
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