Connect Breeching And Venting Systems - Weil-McLain 88 Manual

Connect breeching and venting systems

General venting information
1. Model 88 boilers operate with positive overfire pressure. Adjust
damper assembly (see Figure 49, page 33) during burner start-up
to achieve 0.1" W.C. positive pressure at damper sample hole.
Select type of venting system
Boiler, breeching and stub vent operate at positive pressure. Entire
system must be gas-tight to prevent leaks. Stub vent height must
be limited to prevent negative draft with 3-foot minimum stub
vent height above roof. See Figure 44 and Figure 46.
Boiler operates with positive pressure overfire. Chimney
provide excess draft which may require a barometric draft control
installed and set to provide minimum draft to maintain 0.1" posi-
tive pressure at flue collar. Minimum chimney height above roof
is 3 feet. See Figure 45 and Figure 47.
Construct metal breeching:
1. See Figure 43 for minimum breeching diameter.
2. Select material type and thickness in compliance with local
codes.
Conventional flue pipe should not be used as it could
leak flue gases and carbon monoxide emissions through
seams and joints, resulting in severe personal injury or
death.
3. Refer to ASHRAE Guide for chimney and breeching calculations
and construction and lining.
Long horizontal breechings, excessive number of tees and
elbows or other obstructions restricting combustion gas
flow can result in possibility of condensation, flue gas
leakage and carbon monoxide emissions, causing severe
personal injury or death.
Part No. 550-100-068/1009
Minimum breeching diameter
Boiler I=B=R
model vent or liner diameter
(inches)
Forced Balanced
draft draft
488
10 12
588
10 15
688
12 15
788
12 18
888
14 18
988 14 18
1088
14 21
1188
16 21
1288
16 21
1388
16 24
1488
18 24
1588
18 24
1688 18 24
1788
18 24
1888
20 27
Boiler flue
collar
dimensions
(inches)
10 round
10 round
10 round
12 round
12 round
14 round
14 round
14 round
14 round
14 round
16 round
16 round
16 round
16 x 19 oval
16 x 19 oval
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