Weil-McLain 550-110-710/0107 manual 4b Water piping single-zone system, Closed-type expansion tank

GOLD CGi Gas-Fired Water Boiler — Boiler Manual

4b Water piping — single-zone system

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.

Diaphragm-type or bladder- type expansion tank (Figure 16)

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 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.

Use Figure 16 or Figure 17 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 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.

Figure 16 Diaphragm- or bladder-type expansion	Figure 17 Closed-type expansion tank — Piping
tank — Piping to single-zone system	to single-zone system using closed-
using diaphragm-type or bladder-type	type expansion tank. See Table 6 for
expansion tank. See Table 6 for piping	piping sizes.
sizes.

Part Number 550-110-710/0107 21