Part Number 550-142-302/0520
CGi
SERIES 4 — GAS-FIRED WATER BOILER —
Boiler Manual
27
Piping — low temperature systems
(continued)
4d
1
Boiler isolation (balancing) valves
2
Flow/check
valve
3
System or zone circulator
4
System temperature gauges
5
Zone
valve
6
Drain
valve
7
System temperature valves (see in-
structions to the left for adjusting
valves)
8
Blend temperature gauge
9
Relief valve
10
Automatic air vent (with diaphragm-type expansion tank), or
connect to tank fitting (closed-type expansion 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
Figure 17,
page 21).
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.)
Figure 22
Boiler-bypass piping — Zoning with
circulators — (Alternative to primary/
secondary piping Figures 20 and 21)
Figure 23
Boiler-bypass piping — Zoning with
zone valves — (Alternative to primary/
secondary piping Figures 20 and 21)