Making Tank Piping Connections - AEC A0551794 RS Series Manual

Making Tank Piping Connections

If you have purchased the Screw Compressor central chilling station with the optional
integral pump tank, please proceed with this section.
Note: Thermocouplings for chillers must be installed on both the hot and cold
Freezestat Control
The unit can be equipped with a freezestat control which shuts down the compressor if the
chilled water temperature approaches the freezing point. The chilled water pump on the
system will continue to run. It is factory-set at 40°F (4ºC) or 10°F (6ºC) below the rated
capacity operating temperature of 50°F (10ºC).
If you want lower chilled water temperatures (minimum of 30°F (-1ºC), you'll need to mix
process water with industrial- (not automotive) grade ethylene or propylene glycol with rust
inhibitor to provide protection down to 20°F (12ºC) below the operating temperature you
want. Figure 1 below shows the proper mixtures needed to provide protection to 20°F (12ºC)
below the operating temperature you want. You can then reset the freezestat cutout
temperature to a temperature 10°F (6ºC) below the operating temperature you selected.
Caution!
Figure 1: Freezing Protection Curve
Ethylene
glycol
percent by
volume
Example: Desired leaving temperature = 35°F (1.7ºC),
Screw Compressor Central Chiller
sides of the tank.
Make sure all freezestat adjustments are performed by a qualified
refrigeration service technician.
The manufacturers product warranty does not cover system freeze-up!
Ethylene glycol required for evaporator freeze protection
60
50
40
30
20
10
0
-50ºF -40ºF -30ºF -20ºF -10ºF 0ºF
-46ºC -40ºC -34ºC -29ºC
Chilled water operating temperature ºF / ºC
Glycol % by volume = 35%
This will provide protection to 15°F (-9.4ºC)
Chapter 3: Installation
10ºF 20ºF 30ºF 40ºF 50ºF 60ºF
-23ºC -18ºC -12ºC -7ºC -1ºC 4ºC 10ºC 16ºC
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