Weil-McLain CGi 4 Series Manual page 29

CGi
SERIES 4 — GAS-FIRED WATER BOILER —
4d
Piping — low temperature systems
4e
Water piping — refrigeration system
Figure 25 Piping refrigeration systems
Part Number 550-142-302/0520
Boiler Manual
Figure 24 System-bypass piping — Zoning with
zone valve or circulators, return water
130°F or higher — (Alternative to boiler-
bypass piping Figures 22 and 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 expan-
sion 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 17,
page 21.)
Prevent chilled water from
entering boiler
Install boiler so that chilled medium is piped
in parallel with the heating boiler. Use ap-
propriate valves to prevent chilled medium
from entering boiler. See Figure 18 for typi-
cal installation of balancing valve and check
valve.
If boiler is connected to heating coils located
in air handling units where they can be ex-
posed to refrigerated air, use flow control
valves (see Figure 25) or other automatic
means to prevent gravity circulation during
cooling cycle.
(continued)
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