Smith 28HE Series Installation & Operating Instructions Manual page 5

SERIES 28HE STEAM BOILER INSTALLATION AND OPERATION INSTRUCTIONS
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 fl ue sizes required for the
28HE boilers.
Table 2 - Equivalent Breeching & Chimney Size
Boiler Model Breeching Size
in
28HE-4 10
28HE-5 10
28HE-6 10
28HE-7 12
28HE-8 12
28HE-9 14
28HE-10 14
28HE-11 14
28HE-12 14
28HE-13 14
28HE-14 16
28HE-15 16
28HE-16 16
28HE-17 18
28HE-18 18
Note: These sizes are based on a 20 foot chimney height.
Figure 2- Vertical Venting
Chimney Size
mm in mm
254 10 254
254 10 254
254 10 254
305 12 305
305 12 305
356 14 356
356 14 356
356 14 356
356 14 356
356 14 356
406 16 406
406 16 406
406 16 406
406 18 406
457 18 457
The 28HE is designed for pressurized operation with a
maximum back pressure of 0.10 in, 2.54 mm WC before
the smoke hood slide damper. If the vent confi guration
results in a back pressure greater than this, the burner
capacity may have to be verifi ed. Contact the Smith
Technical Service Department to verify the burner
capacity.
The chimney must be able to provide 0.10 in. WC at
the boiler outlet. If the chimney is 50 ft. or taller it may
produce excessive draft (appox. - 0.25 in. WC) and a
barometric draft regulator may be needed.
When more than one appliance is connected to the
same chimney fl ue the fl ue 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
fl ue, never connect a Category I appliance to this
fl ue. Doing so can result in the accumulation
of carbon monoxide which can cause severe
personal injury or death!
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