Weil-McLain CGi 4 Series Manual page 23

CGi
SERIES 4 — GAS-FIRED WATER BOILER —
4c
Water piping — multiple zones
Figure 18 Zoning with circulators
Boiler isolation (balancing)
1
valves
Flow/check valve
2
System or zone circulator
3
Zone valve
5
Drain valve
6
Relief valve
9
Part Number 550-142-302/0124
Boiler Manual
— return water 130°F or higher.
For systems with possible low return-water temperature (such as converted gravity
systems, radiant heating systems and heat pump systems), refer to the special
piping suggestions of
return water temperature to the boiler could cause corrosion of the boiler sections,
resulting in severe personal injury, death or substantial property damage.
Figure 19 Zoning with zone valves
Automatic air vent (with diaphragm-type expansion tank), or
10
connect to tank fitting (closed-type expansion tank).
use an automatic air vent when using closed-type expansion
tank. It would allow air to leave the system, causing waterlog-
ging of the expansion tank.
Fill valve
11
Diaphragm-type or bladder-type expansion tank, if used (For
12
closed-type expansion tank, pipe from top of air separator to
tank fitting as in
Figure 17
Air separator and automatic vent, if used (Note that the fill
13
valve must always be connected to the expansion tank,
regardless of location of expansion tank circulator or air
separator.
, as applies. Failure to prevent sustained low
Figures 20 – 24
(continued)
— return water 130°F or higher.
.)
DO NOT
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