Weil-McLain 550-110-260/0107 manual 3b Water piping — single-zonesystem, Diaphragm-typeor bladder

GOLD CGs Gas-Fired Water Boiler — Boiler Manual

3b Water piping — single-zone system

Diaphragm-type or bladder-	Closed-type expansion tank
type expansion tank (Figure 4)	(Figure 5)

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 in air vent tapping as shown.

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.

Use Figure 4 or Figure 5 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 18-23. 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 4	Diaphragm- or bladder-type expansion tank Figure 5	Closed-type expansion tank
	Piping to single-zone system	Piping to single-zone system
	See Table 3 for piping sizes.	See Table 3 for piping sizes.

Part number 550-110-260/0107

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