SERIES 28A BOILER INSTALLATION AND OPERATION INSTRUCTIONS

Page 5

Chimney Inspection & Sizing

If this boiler will be connected to a masonry chimney, a thorough inspection of the chimney must be performed. Ensure that the chimney is clean, properly constructed, lined and properly sized, see Figure 2. Table 2 lists the equivalent breeching and flue sizes required for the 28A boilers.

Table 2 - Equivalent Breeching & Chimney Size

Boiler Model

Breeching Size

Chimney Size

 

in

mm

in

mm

28A-4

10

254

10

254

28A-5

10

254

10

254

28A-6

10

254

10

254

28A-7

12

305

12

305

28A-8

12

305

12

305

28A-9

14

356

14

356

28A-10

14

356

14

356

28A-11

14

356

14

356

28A-12

14

356

14

356

28A-13

14

356

14

356

28A-14

16

406

16

406

28A-15

16

406

16

406

28A-16

16

406

16

406

28A-17

18

406

18

406

28A-18

18

457

18

457

Note: These sizes are based on a 20 foot chimney height.

The 28A is designed for pressurized operation with a back pressure of 0.10 in, 2.54 mm W.C. before the smoke hood slide damper. If the vent configuration results in a back pressure greater than this, the burner capacity may have to be verified. Contact the Smith Technical Service Department to verify the burner capacity.

The chimney must be able to provide 0.10" WC at the boiler outlet. If the chimney is 50 ft. or taller it may produce excessive draft (approx. - 0.25" WC) and a barometric draft regulator may be needed.

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 the appliances.

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

Figure 2 - Vertical Venting