Williamson-Thermoflo GWC-070 Manual page 26

GWC -
gas fired water boiler
Multiple boiler water piping
Piping layout — typical for multiple GWC boilers, using secondary headers (2-boiler system)
Figure 33
1 Flow/check valve (each boiler)
2 Isolation valves (when used)
3 Caps
4 Secondary header (supply) — layout and size per page 24
5 Secondary header (return) — layout and size per page 24
6 Primary circulator
7 Expansion tank (diaphragm type)
8 System air eliminator
9 System automatic air vent
16 Cold water fill line — see Figure 32, page 25 for typical com-
ponents
26
— Boiler Manual
(continued)
Legend — Figure 33
17 3-way diverting valve (operated by DHW aquastat — valve end
switch connects across boiler thermostat terminals)
18 System supply
19 System return
20 Boiler relief valve and discharge piping, installed per GWC Boiler
Manual
21 Indirect-fired storage water heaters — Example is shown connect-
ed to one boiler of the system. The indirect water heater could
also be connected with a secondary connection off the main
header, as in Figure 34, page 27.
Part number 550-142-056/0411