SERVICE TECHNICIAN ONLY — read and follow completely.
Boiler
Size
Minimum
breeching
diameter
(Note 3)
Minimum
AHRI
chimney size
Minimum
chimney
height
Rect .
Round
WGO-2
5"
8" x 8"
(Note 1)
6"
15'
WGO-3
WGO-4
6"
WGO-5
6"
8" x 8"
(Note 1)
7"
15'
WGO-6
7"
WGO-7
WGO-8
7"
8" x 12"
(Note 2)
7"
20'
WGO-9
NOTE:
1 6¾" x 6¾" inside liner
2 6½" x 10½" inside liner
3 Flue collar on boiler is 7" diameter
Connect breeching
General chimney requirements
•
Designed for natural draft firing. Connect boiler to vertical
chimney.
•
Insufficient draft can cause flue gas leakage and carbon monoxide
emissions, which will lead to severe personal injury or death.
•
Use vent material approved by local codes for oil-fired burners.
In their absence, refer to:
•
NFPA 31 – latest edition, Installation of Oil-Burning Equip-
ment.
•
NFPA 211 – latest edition, Standard for Chimneys, Fireplaces,
Vents and Solid Fuel Burning Appliances.
•
In Canada, refer to CSA B139, Installation Code for Oil-
Burning Equipment.
•
NFPA 211 requires chimney to be lined before connected to boiler.
•
Inspect existing chimney before installing new boiler. Failure to do
any of the following will result in severe personal injury or death:
•
Clean chimney, including removal of blockage.
•
Repair or replace damaged pipe or liner.
•
Repair mortar and joints.
•
To prevent downdrafts, extend chimney at least 3 feet above
highest point where it passes through roof and 2 feet higher than
any portion of building within 10 feet. Increase chimney cross-
sectional area and height at least 4% per 1,000 feet above sea level.
•
Minimum clearances from vent pipe to combustible material:
•
6 inches — Type “L” double-wall vent
•
9 inches — Single-wall vent
•
Minimum chimney sizes should be used.
Oversized chimneys, outside masonry chimneys and/or
derated inputs can result in condensation in chimney.
Connect breeching:
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, which can
lead to severe personal injury or death.
1. Install two (2) flue pipe brackets.
2. Connect full-sized breeching when possible. See Minimum Chim-
ney Size, see Table 3.
•
Back outlet — see Figures 7 and 9, page 17.
•
Top outlet — see Figures 8 and 10, page 17.
3. Connection must be made above bottom of chimney to avoid
blockage. Breeching must not enter chimney far enough to cause
obstruction. Use thimble or slip joint where breeching enters
chimney to allow removal for cleaning.
4. When burner and boiler are properly installed, draft overfire will
be approximately -0.01” to -0.02” W.C. Install barometric control
in breeching, per control manufacturer’s instructions, when excess
draft needs to be relieved or to comply with applicable codes and
regulations. Use draft gauge to adjust proper opening.
Table 3
Minimum chimney sizes
5. An induced draft fan for the chimney may be neces-
sary if:
•
Excessive resistance to flow of combustion gases
can be expected.
•
Cross-sectional area of chimney is smaller than
minimum recommended.
•
Chimney height is less than recommended.
Seal all vent joints. Interlock burner with fan
operation.
6. Boiler models ending in “D”, such as WGO-3D, require
the installation of the Field Controls OVD-7 automatic
damper kit, Weil-McLain part number 381-800-515.
Refer to Figures 7 and 8, page 17.
Part number 550-142-331/0421
16
WGO
OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4—
Boiler Manual
