Weil-McLain Gold CGi 2 Series Manual page 21

CGi
GOLD GAS-FIRED WATER BOILER — SERIES 2 —
4b
Water piping — single-zone system
Diaphragm-type or bladder-
type expansion tank
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
Figure 16
Part Number 550-110-710/1211
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.
(Figure 16)
automatic air vent as shown.
Figure 16 Figure 17
Use or
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 24-29. 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.
Diaphragm- or bladder-type expansion
tank — Piping to single-zone system
using diaphragm-type or bladder-type
expansion tank. See Table 6 for piping
sizes.
Boiler Manual
Closed-type expansion tank
(Figure 17)
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.
only for single-zone systems designed for return water at least 130°F.
Figure 17 Closed-type expansion tank — Piping
to single-zone system using closed-
type expansion tank. See Table 6 for
piping sizes.
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