Weil-McLain CGi 4 Series Manual page 25

CGi
SERIES 4 — GAS-FIRED WATER BOILER —
4d
Piping — low temperature systems
Figure 20
Boiler isolation (balancing) valves
1
Flow/check valve
2
System or zone circulator
3
System temperature gauges
4
Zone valve
5
Drain valve
6
System temperature valves (see instruc-
7
tions to the left for adjusting valves)
Blend temperature gauge
8
Part Number 550-142-302/0520
Primary/secondary piping
Zoning with circulators
Boiler Manual
Figure 21 Primary/secondary piping
Zoning with zone valves
Relief valve
9
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 waterlogging of
the expansion tank.
Fill valve
11
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
Air separator and automatic vent, if used (Note that the fill valve
13
must always be connected to the expansion tank, regardless of
location of expansion tank, circulator or air separator.)
(continued)
DO NOT
.)
25