16
Part Number 550-142-320/0720
GWA
Series 3
Gas-Fired Water Boilers –
Boiler Manual
4 Water piping — multiple zones
continued
1
Boiler
isolation (balancing) valves
2
Flow/check
valve
3
System
or zone circulator (circulator should
cycle with zone valve and switches, using cir-
culator 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
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 sepa-
rator to tank fitting as in Figure 6, page 11.)
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 12
Primary/secondary piping
Zoning with circulators
Figure 13
Primary/secondary piping
Zoning with zone valves
Water piping — low temperature systems
continued
