Weil-McLain CGA Series 2 Manual page 25

CGa Series 2 Gas-Fired Water Boiler — Boiler Manual
3d
Water piping — low temperature systems
3e
Water piping — refrigeration systems
Figure 18 Piping refrigeration systems
Part Number 550-142-900/0519
Figure 17
System-bypass piping — Zoning with
zone valve or circulators, return water
130°F or higher — (Alternative to boiler-
bypass piping Figures 15 and 16,
page 23)
3 System or zone circulator
7 System temperature valves (see instructions to the left for
adjusting valves)
8 Blend temperature gauge
9 Relief valve
10 Automatic air vent (with diaphragm-type expansion
tank), or connect to tank fitting (closed-type expansion
tank). DO NOT use an automatic air vent when using
closed-type expansion tank. It would allow air to leave
the system, causing waterlogging of the expansion tank.
11 Fill valve
12 Diaphragm-type or bladder-type expansion tank, if used
(For closed-type expansion tank, pipe from top of air
separator to tank fitting as in Figure 10
Prevent chilled water from
entering boiler
Install boiler so that chilled medium is piped in parallel
with the heating boiler. Use appropriate valves to prevent
chilled medium from entering boiler. See Figure 18 for
typical installation of balancing valve and check valve.
If boiler is connected to heating coils located in air han-
dling units where they can be exposed to refrigerated
air, use flow control valves or other automatic means to
prevent gravity circulation during cooling cycle.
(continued)
, page 17
.)
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