Smith Cast Iron Boilers GS110W operation manual Vertical Vent Positive Pressure Systems

Page 12 GS110 DIRECT VENT BOILER INSTALLATION AND OPERATION INSTRUCTIONS

VERTICAL VENT

POSITIVE PRESSURE SYSTEMS

See Figure 11. The vent materials used in vertical positive pressure vent systems must be certified to UL 1738 for installations in the United States, ULS636 for installations in Canada.

The maximum vent lengths are listed in Table 3.

Each 90° elbow is equal to 5 linear feet (1.5 m) of pipe. To maximize the performance of single wall sheet metal vent systems locate 90° elbows as far from the boiler as possible and from one another. If any part of a single wall metal vent system passes through an unheated space it must be insulated with insulation rated for 400

°F. Structural penetrations must be made using approved fire-stops.

The vent system must be both gas-tight and watertight. All seams and joints in metal pipes must be joined and sealed in accordance with the vent system manufacturer's instructions. Vertical vent systems must terminate as shown in Figures 6 & 11. An approved terminal cap must be used.

VERTICAL VENT

NEGATIVE PRESSURE SYSTEMS

See Figures 4, 5 & 9. The GS110 is listed as a Category I appliance when vented vertically into a metal chimney system or masonry chimney sized as listed in Table 6.

WARNING: If an appliance using any type of a mechanical draft system operating under positive pressure is connected to a chimney flue, never connect any other appliances to this flue. Doing so can result in excessive levels of carbon monoxide which can cause severe personal injury or death!

Chimney Inspection & Sizing

A thorough inspection of the masonry chimney must be performed to ensure that the chimney is clean, properly constructed and properly sized. Exterior masonry chimneys should not be used unless properly lined to prevent condensation and draft problems. Table 6 lists the equivalent breeching and flue sizes required for the boiler/water heater. When more than one appliance is connected to the same chimney flue the flue must be large enough to safely vent the combined output of all of the appliances.

Table 6 - Equivalent Breeching & Chimney Size

Boiler	Vent & Chimney Diameter	Intake Diameter
Model	inches (mm)	inches (mm)
GS110-3	3 (7.6)	3 (7.6)
GS110-4	4 (10.2)	3 (7.6)
GS110-5	4 (10.2)	3 (7.6)
GS110-6	5 (12.7)	4 (10.2)
GS110-7	5 (12.7)	4 (10.2)

Note: These sizes are based on a 20 foot (6.1m) chimney height.