Part number 550-110-260/0107
17
GOLD CGs Gas-Fired Water Boiler — Boiler Manual
Figure 6 Zoning with circulators
— return water 130°F or higher.
Figure 7 Zoning with zone valves
— return water 130°F or higher.
1 Boiler isolation (balancing)
valves
2 Flow/check valve
3 System or zone circulator
5 Zone valve
6 Drain valve
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 5, page 15.)
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.
3c Water piping — multiple zones (continued)
For systems with possible low return-water temperature (such as converted gravity systems,
radiant heating systems and heat pump systems), refer to the special piping suggestions of
Figures 8 - 12, as applies. Failure to prevent sustained low return water temperature to the
boiler could cause corrosion of the boiler sections, resulting in severe personal injury, death
or substantial property damage.