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Part Number 550-101-009/0107
17
GOLD CGa Gas-Fired Water Boiler — Boiler Manual
Diaphragm-type or bladder-
type expansion tank (Figure 9)
1. Ensure expansion tank size will handle boiler and
system water volume and temperature. Tank must
be located in boiler return piping as close to boiler
as possible, before inlet side of circulator. See tank
manufacturer’s instructions for details.
2. Install an
automatic air vent as shown.
Closed-type expansion tank
(Figure 10)
1. Ensure expansion tank size will handle boiler and
system water volume and temperature. See tank
manufacturer’s instructions for details.
2. Connect tank to ½” NPT tapping located behind
supply outlet, using ½” NPT piping. Pitch any
horizontal piping up towards tank 1 inch per 5 feet
of piping.
Undersized expansion tanks cause system water to be lost from relief valve and makeup water
to be added through fill valve. Eventual section failure can result.
Water piping — single-zone system
Figure 9 Diaphragm- or bladder-type expansion
tank — Single-zone system using dia-
phragm-type or bladder-type expansion
tank. See Table 3 for piping sizes.
Figure 10 Closed-type expansion tank — Single-
zone system using closed-type expan-
sion tank. See Table 3 for piping sizes.
3b
Use Figure 9 or Figure 10 only for single-zone systems designed for return water at least
130°F. For systems with low return water temperature possible, such as converted gravity
systems and radiant heating systems, refer to the special piping suggestions of pages 20-25.
Failure to prevent low return water temperature to the boiler could cause corrosion of the
boiler sections or burners, resulting in severe personal injury, death or substantial property
damage.