Sterlco 30RA Outdoor Air Cooled Central Chillers 10-60 Tons - Manual (Page 12)

12
Step 4 — Cooler Fluid and Drain Piping Con-
nections (Units with Factory-Installed Hy-
dronic Packages)
WATER SYSTEM OVERVIEW — The 30RA chillers with
factory-installed hydronic packages are designed for use with
closed systems, meaning that there is no more than one water-
air interface in the water loop. Cooling tower loops, for
example, have two water-air interfaces (sump and nozzles) and
would thus be classified as open, whereas a correctly designed
chilled water loop with the only water-air interface being in the
expansion tank is closed. Since closed and open water systems
behave very differently, these instructions assume that the
chilled water loop is closed. A system installed incorrectly such
that air is not handled properly — pipe leaks, vent leaks, air in
pipes, etc. — may behave as an open system and thus have
unsatisfactory operation. Pump seal wear can also cause leaks
that cause poor system operation.
Proper closed system design and installation procedures
should be followed closely. The system must be constructed
with pressure tight components and thoroughly tested for
installation leaks. Factory-supplied hydronic systems are avail-
able with single or dual (for back-up) pumps. The factory-
installed system includes all of the components within the
dashed lines in Fig. 10.
Installation of water systems should follow sound engineer-
ing practice as well as applicable local and industry standards.
Improperly designed or installed systems may cause unsatis-
factory operation and/or system failure. Consult a water treat-
ment specialist or appropriate literature for information regard-
ing filtration, water treatment, and control devices. Figure 10
shows a typical installation with components that might be in-
stalled with the hydronic package of the 30RA unit. Figure 11
illustrates a typical dual pump package for the 010-030 size
models.
NOTE: It is recommended that isolation (shut-off) valves be
placed exterior to the unit to allow removal and service of
the entire pump assembly, if necessary. Also, if the unit is
isolated with valves, a properly sized pressure relief valve
should be installed in the piping between the unit and the
valves, following all applicable state and local codes.
8
9
10
12 11
14
12 11
13
2
1
3
4
5
6
7
6
FS
LEGEND
1 — Strainer/Blow-Down Valve
2 — Expansion Tank
3 — Pump
4 — Electric Heater
5 — Air Vent Connection Port
6 — Pressure Gages/Petcocks
7 — Heat Exchanger
8 — Flow Switch
9 — Balancing Valve Balance
Valve/Drain Plug
10 — Pressure Relief
11 — Isolation Valves
12 — Flex Connections
13 — Pressure Reducing/Fill Valve
14 — Air Separator and Vent
Fig. 10 — Typical Piping Diagram on 30RA Units With Hydronic Package
5
6
7
1
2 4
3
LEGEND
1 — Strainer
2 — Blow-Down Valve
3 — Discharge Check Valve
(Dual Pumps Only)
4 — Balancing Valve with Drain Plug
5 — Flow Switch
6 — Field Connections
7 — Heater
Fig. 11 — Typical Dual Pump Package