Williamson-Thermoflo GWC-070 Manual page 25

GWC -
gas fired water boiler
Multiple boiler water piping
Piping schematic — typical for multiple GWC boilers, using secondary headers
Figure 32
1 Flow/check valve (each boiler)
2 Isolation valves (when used)
3 Cap
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
10 Pressure reducing valve
Part number 550-142-056/0411
— Boiler Manual
(continued)
Legend — Figure 32
11 Check valve or backflow preventer, as required by applicable
codes
12 Isolation valve
13 Water flow switch (when used)
14 Supply water temperature control (when used)
15 Low water cutoff (when used) (place above primary header)
16 Cold water fill line — see Figure 15, page 14 for typical
components
18 System supply
19 System return
20 (Not shown) Boiler relief valve and discharge piping, installed
per GWC Boiler Manual
30 Long end of secondary header
25