CGi Manual

Part Number 550-142-302/0520
CGi
SERIES 4 — GAS-FIRED WATER BOILER — Boiler Manual
29
Piping — low temperature systems (continued)
4d
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.)
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)
Figure 25 Piping refrigeration systems
4e
Water piping — refrigeration system
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.