Weil-McLain CGa 3 Series Manual page 21

CGa Series 3 Gas-Fired Water Boiler — Boiler Manual
3d
Water piping — low temperature systems
Figure 13
1
Boiler isolation (balancing) valves
2
Flow/check valve
3
System or zone circulator (circulator should cycle
with zone valve and switches, using circulator valve
or zone control panel)
4
System temperature gauges
5
Zone valve
6
Drain valve
7
System temperature valves (see instructions to the
left for adjusting valves)
8
Blend temperature gauge
9
Relief valve
Part Number 550-142-300/0520
Primary/secondary piping
Zoning with circulators
Figure 14 Primary/secondary piping
Zoning with zone valves
10
Automatic air vent (with diaphragm-type expansion
tank), or connect to tank fitting (closed-type expan-
sion 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
page 17.)
13
Air separator and automatic vent, if used (Note that
the fill valve must always be connected to the expan-
sion tank, regardless of location of expansion tank,
circulator or air separator.)
(continued)
Figure 10
,
21