Weil-McLain 550-110-260/0107 manual 3a Water piping general information

GOLD CGs Gas-Fired Water Boiler — Boiler Manual

3a Water piping — general information

General piping information

If installation is to comply with ASME or Canadian requirements, an ad- ditional high temperature limit is needed. Install control in supply piping between boiler and isolation valve. Set second control to minimum 20°F above setpoint of first control. Maximum allowable setpoint is 240°F. See Section 9b, page 32 for wiring.

A low water cutoff device is required when boiler is installed above ra- diation level or by certain state or local codes or insurance companies. Use low water cutoff designed for water installations. Electrode probe-type is recommended. Purchase and install in tee in supply piping above boiler.

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

Circulator

The circulator is shipped loose (wiring pre-attached to boiler) to allow you to locate it either in the return or supply piping, as desired. See page 3 for a typical instal- lation. Pipe the expansion tank to the suction side of the circulator whenever possible. Install an air separator in the supply piping. Connect the expansion tank to the air separator only if the separator is on the suction side of the circulator. Always install the system fill connection at the same point as the expansion tank connection to the system. Figures 4 and 5, page 15, show typical near- boiler piping connections.

Pressure/temperature gauge

Install pressure/temperature gauge in tee on supply piping (as shown in drawing on page 3).

Relief valve

Install relief valve vertically in ¾” tapping on side of boiler. See Figure 4 or 5, page 15, and the tag attached to the relief valve for manufacturer’s instructions.

To avoid water damage or scalding due to relief valve operation:

•Discharge line must be connected to relief valve outlet and run to a safe place of disposal. Terminate the discharge line to eliminate possibility of severe burns should the valve discharge.

•Discharge line must be as short as possible and be the same size as the valve discharge connection throughout its entire length.

•Discharge line must pitch downward from the valve and terminate at least 6” above the floor drain where any discharge will be clearly visible.

•The discharge line shall terminate plain, not threaded, with a mate- rial serviceable for temperatures of 375°F or greater.

•Do not pipe the discharge to any place where freezing could occur.

•No shutoff valve shall be installed between the relief valve and boiler, or in the discharge line. Do not plug or place any obstruction in the discharge line.

•Failure to comply with the above guidelines could result in failure of the relief valve to operate, resulting in possibility of severe personal injury, death or substantial property damage.

•Test the operation of the valve after filling and pressurizing system by lifting the lever. Make sure the valve discharges freely. If the valve fails to operate correctly, replace it with a new relief valve.

System water piping

See Figure 4 (diaphragm-type or bladder-type expan- sion tank) or Figure 5 (closed-type expansion tank) on page 15, and Table 3 below, for near-boiler and single- zone systems designed for return water at least 130°F.

See pages 16-17 to complete multiple-zone piping or pages 18-23 to complete piping for radiant heating systems or converted gravity systems (large-volume systems originally designed for circulation by natural convection rather than a pump).

Table 3  Water pipe size (based on 20°F rise)

Boiler	To	From
model	system	system
number
CGs-3/4/5	1"	1"
CGs-6	1 ¼"	1 ¼"

Note: The boiler supply and return connections, the return/ drain tee and the supply/gauge tee supplied with the boiler are 1¼” NPT. One of the circulator flanges sup- plied with the boiler is 1¼”. The other circulator flange is the size of the recommended system piping shown above.

Chillers or air handling units:

Install boiler such that —

•Chilled medium, if used, is piped in parallel with heating boiler. Use appropriate valves to prevent chilled medium from entering boiler. Consult I=B=R Installation and Piping Guides.

•If boiler is connected to heating coils located in air handling units where they can be exposed to refrigerated air, use flow control valves or other au- tomatic means to prevent gravity circulation during cooling cycle. Circulation of cold water through the boiler could result in damage to the heat exchanger, causing possible severe personal injury, death or substantial property damage.

14

Part number 550-110-260/0107