Weil-McLain 550-141-827/1201 Connect Water Piping, General piping information, Install piping

Connect Water Piping

General piping information:

•If installation is to comply with ASME or Canadian requirements, an additional high temperature limit is needed. Install control in supply piping between boiler and isolation valve. Set control to a minimum of 20°F above set point of combination control. Maximum allowable set point is 220°F. Wire control as shown on wiring diagram.

•Use a low water cutoff device when:

—Boiler is installed above radiation level.

—Required by certain state or local codes or insurance companies.

Use low water cutoff designed for water installations. Probe-type is recommended. Purchase and install in tee in supply line above boiler.

•Use backflow check valve in cold water supply as required by local codes.

•“A2” or “A3” tapping not recommended for system supply piping. If “A2” or “A3” tapping must be used, adequate air elimination method must be provided.

Install piping:

•See FIGURE 7 or 8 on page 13 and Water Piping Size Table at right for near-boiler piping and single-zone piping. See page 14 to complete multiple-zone piping or page 15 to complete piping for systems operating below 140°F.

For multiple-boiler piping, refer to Weil-McLain’s “Primary/Secondary Piping Guide."

•Install relief valve vertically in “R” tapping

on back of boiler. See FIGURE 7 or 8 and also refer to tag attached to relief valve for manufacturer’s instructions.

Pipe relief valve discharge line near floor close to floor drain to

eliminate potential of severe burns. Do not pipe to any area where freezing could occur. Do not plug, valve or place any obstruction in discharge line.

DIAPHRAGM expansion tank (FIGURE 7):

•Make sure expansion tank size will handle boiler and system water volume and temperature. Tank must be located near boiler before inlet to circulator. See tank manufacturer’s instructions for details.

Undersized expansion tanks cause system water to be lost from relief

valve and makeup water added through fill valve. Eventual section failure can result.

•Install automatic air vent in “A2” tapping as shown in FIGURE 7.

CLOSED expansion tank (FIGURE 8):

•Ensure expansion tank size will handle boiler and system water volume and temperature.

Undersized expansion tanks cause system water to be lost from relief

valve and makeup water added through fill valve. Eventual section failure can result.

•Connect tank from “A2” tapping shown in FIGURE 8 to expansion tank. Use 1¼2 " N.P.T. piping. Pitch any horizontal piping up towards tank 1 inch per 5 feet of piping.

WATER PIPING SIZE TABLE*

BOILER
MODEL	TO	FROM
NUMBER	SYSTEM	SYSTEM
SGO-3W	1¼"	1¼"
SGO-4W	1¼"	1¼"
SGO-5W	1½"	1½"
SGO-6W	1½"	11¼2"
SGO-7W	1½"	1½"
SGO-8W	2"	2"
SGO-9W	2"	2"

*All piping sizes based on 20°F temperature rise through boiler.

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