Weil-McLain CGi 4 Series Manual page 27

CGi
SERIES 4 — GAS-FIRED WATER BOILER —
4d
Piping — low temperature systems
Figure 22
Boiler isolation (balancing) valves
1
2 Flow/check valve
System or zone circulator
3
4 System temperature gauges
Zone valve
5
6 Drain valve
System temperature valves (see in-
7
structions to the left for adjusting
valves)
Blend temperature gauge
8
Part Number 550-142-302/0520
Boiler-bypass piping — Zoning with
circulators — (Alternative to primary/
secondary piping Figures 20 and 21)
Boiler Manual
Figure 23 Boiler-bypass piping — Zoning with
zone valves — (Alternative to primary/
secondary piping Figures 20 and 21)
Relief valve
9
Automatic air vent (with diaphragm-type expansion tank), or
10
connect to tank fitting (closed-type expansion tank).
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
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,
13 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)
DO NOT
page 21).
use
27