Williamson-Thermoflo GWA 3 Series Manual page 18

GWA Series 3 Gas-Fired Water Boilers – Boiler Manual
4 Water piping — multiple zones
Water piping — low temperature systems
Figure 14 Boiler-bypass piping
Zoning with circulators (Alternative to
primary/secondary piping Figures 12 and 13)
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 instructions to the
left for adjusting valves)
8 Blend temperature gauge
9 Relief valve
18
continued
Figure 15
Boiler-bypass piping
Zoning with zone valves (Alternative to primary/
secondary piping Figures 12 and 13)
10 Automatic air vent (with diaphragm-type expansion tank), or
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 waterlog-
ging 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 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.)
continued
DO NOT
Part Number 550-142-320/0720