UTICA BOILERS SFM6225W Installation, Operation And Maintenance Manual page 12

VENTING SYSTEM INSPECTION & INSTALLATION
An unlined chimney will have leaks that will cause
poor chimney performance (NO DRAFT), and could
result in poor positive pressure in the combustion
chamber.
Horizontal portions of the venting system should
not exceed 10 feet in length. Horizontal lengths
over 10 feet will have a negative effect on the
chimney performance.
The chimney should extend at least 2 feet above
any portion of the building within 10 feet. See
figure 5 at right. It should produce a negative draft
of .06 to .08 inches of water column, (W.C.), as
measured with a draft gauge between the boiler
and barometric draft control while maintaining an
.02 inch W.C. negative draft in the combustion
chamber. See chart below for recommended
chimney or vent sizes.
Inadequate draft will cause improper combustion,
resulting in dirty flue ways and high fuel bills.
When installing a single boiler, connect the flue
pipe with the same size
as the boiler outlet to the
chimney, sloping upward
continuously toward the
chimney approximately ¼"
per foot. Bolt or screw joints
together to avoid sag.
If an oil fired water heater
is vented into the same
flue as the boiler, provide
a separate hole into the
chimney whenever pos-
sible. When this isn't pos-
sible, use a "Y" connection
in the flue pipe, using a
separate draft regulator for
each unit. When a chimney
will not provide adequate
draft to handle the input
from the water heater and
boiler simultaneously, wire
the units so that only one will operate at a time,
favoring the water heater.
MODEL NO.
SFM6225W
SFM7275W
SFM24150W
SFM25175W
SFM25200W
SFM26225W
SFM27275W
SFM36225W
SFM37275W
SFM47275W
SFM57275W
SFM67275W
SFM77275W
SFM87275W
figure #6
TYpical VenTing of 2 or More uniTs
12
CHIMNEY OR VENT SIZES
DIA. OF
CHIMNEY CHIMNEY SIZE
OPENING (IN. X IN. X FT.)
(BREECHING)
8 8X8X15
9 8X12X15
9 8X12X15
9 8X12X20
9 8X12X20
9 8X12X20
10 12X16X15
12 12X16X15
14 12X16X20
14 12X16X15
18 16X20X20
18 20X20X15
22 20X24X15
22 20X24X20
FLUE
OUTLET
SIZE
8"
8"
6"
7"
7"
8"
8"
8"
8"
8"
8"
8"
8"
8"