IMM AGS-2
19
Chilled Water Pump
It is recommended that the chilled water pumps' starters be wired to, and controlled by, the
chiller's microprocessor. The controller will energize the pump whenever at least one
circuit on the chiller is
enabled
to run, whether there is a call for cooling or not. Wiring
connection points are shown in Figure 23 on page 42.
Water Piping
Due to the variety of piping practices, follow the recommendations of local authorities.
They can supply the installer with the proper building and safety codes required for a
proper installation.
Design the piping 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.
3.
Manual or automatic air vent valves at the high points of the system and drains at the
low parts in the system. The evaporator should not be the highest point in the piping
system.
4.
Some means of maintaining adequate system water pressure (i.e., expansion tank or
regulating valve).
5.
Water temperature and pressure indicators located at the evaporator inlet and outlet to
aid in unit servicing. Any connections should be made prior to filling the system with
water.
6.
A strainer to remove foreign matter from the water before it enters the pump. Place the
strainer 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.
NOTE
:
A 40 mesh strainer must also be placed in the supply water line just prior to
the inlet of the evaporator. This will aid in preventing foreign material from entering
the evaporator and causing damage or decreasing its performance. Care must also be
exercised if welding pipe or flanges to the evaporator connections to prevent any weld
slag from entering the vessel.
7.
Any water piping to the unit must be protected to prevent freeze-up if below freezing
temperatures are expected.
CAUTION
If a separate disconnect is used for the 115V supply to the unit, it should power the
entire control circuit, not just the evaporator heaters. It should be clearly marked
so that it is not accidentally shut off during cold seasons. Freeze damage to the
evaporator could result. If the evaporator is drained for winter freeze protection,
the heaters must be
de-energized
to prevent burnout.
8.
If the unit is used as a replacement chiller on a previously existing piping system, flush
the system thoroughly prior to unit installation. Perform regular chilled water analysis
and chemical water treatment immediately at equipment start-up.
