Fulton Classic ICX or FB-F Vertical Tubeless Boilers (Steam) Oil Fired - Manual (Page 26)

Description/Instructions
18-O 4/00
Exhaust Side Wall Venting (UL
and MEA Approved- MEA File
Number 68-79-E Vol. 2 )
a) Boilers for which sidewall venting
may be utilized are No. 2 oil, natural
gas, or combination No. 2 oil and
natural gas,sizes 4 to 30 H.P. The
following criteria is required for
installations using sidewall venting:
1) Flue vent piping shall be pitched
upward at 1/4" per foot of length.
2) A U.L. Approved draft fan must be
installed to provide sufficient draft
(-.02 and -.04 " W.C. pressure
-0.508 to -1.016 mm) to safely vent
the products of combustion.
3) The draft fan should be
located as close to the flue outlet
as possible.
4) Draft regulation sufficient to
lower the draft to between -.02 and
-.04 " W.C. pressure (-0.508 to
-1.016 mm) may be required. The
draft regulator(s) must be between
the boiler and draft fan.
5) The draft fan shall have an air
flow proving switch wired in series
with the boiler air safety switch.
6) The sidewall vent total length
from boiler exhaust to termination
shall not exceed 35 feet (10.7 m)
with 4 elbows maximum.
Corrosion of flue pipe
a) In the case of a combustion flue
pipe, acid may develop over a long
period of time per the following
process. Chlorine containing gases,
such as halocarbon refrigerants,
carbon tetrachloride, trichlorethyl-
ene, or pechlorethylene, when
drawn into combustion air are bro-
ken down into elemental chlorine
gas which exits up the flue pipe. If
the flue pipe is cold, as it would be if
the combustion process had been
off for some time, the water vapor
condenses in the flue pipe during
the first few minutes of ignition and
the chlorine in the combustion gas
dissolves in the water --forming
hydrochloric acid. As the combus-
tion system flue line increases in
temperature, the water vapor no
longer condenses because the flue
temperature is above the dew point
of the combustion gas. The com-
bustion gas then dries out (dehy-
drates) the hydrochloric acid solu-
tion leaving behind dry chloride salt.
b) When the next cold start-up
occurs, the process repeats except
that more and more chloride collects
and concentrates along the flue. As
the quantity of chloride increases it
does not dehydrate completely as
the flue heats up and a corrosive
poultice develops which attacks the
steel and will also attack the boiler.
c) Concentration levels of only a
few ppm of chlorine containing
compounds in combustion air can
produce serious corrosion over long
periods of time. High chlorine con-
taining compounds such as carbon
tetrachloride or perchlorethylene
would be prime suspects.
Air Flow
Safety Switch
U.L. Approved
Induced Draft Fan
Side Wall
Vent
Termination
(By Others)
Side Wall Vent
(By Others)