Weil-McLain CGA Series 2 Manual page 19

CGa Series 2 Gas-Fired Water Boiler — Boiler Manual
3c
Water piping — multiple zones
Figure 11
1
Boiler isolation (balancing)
valves
2
Flow/check valve
3
System or zone circulator
5
Zone valve
6
Drain valve
9
Relief valve
Part Number 550-142-900/0519
Zoning with circulators — return water
130°F or higher.
10
11
12
13
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
Figures 13 – 17
, as applies. Failure to prevent sustained low return water temperature to
the boiler could cause corrosion of the boiler sections, resulting in severe personal injury,
death or substantial property damage.
Figure 12
Automatic air vent (with diaphragm-type expansion tank), or connect
to tank fitting (closed-type expansion tank).
air vent when using closed-type expansion tank. It would allow air to
leave the system, causing waterlogging of the expansion tank.
Fill valve
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 , page 17.)
Air separator and automatic vent, if used (Note that the fill valve must
always be connected to the expansion tank, regardless of location of
expansion tank circulator or air separator.
(continued)
Zoning with zone valves — return water
130°F or higher.
DO NOT
use an automatic
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