Weil-McLain WTGO - Page 35

Part number 550-141-825/1211
35
GOLD
WTGO
OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — Boiler Manual
SERVICE TECHNICIAN ONLY — read and follow completely.
Dimension A
(When desired minimum
clearance from
Type “L” double-wall
vent pipe to combustible
surface is:)
Use the following
protection**:
3"
½” thick insulation board
***
over one-inch glass fiber or
mineral wool batts+
2"
24 gauge sheet metal with
one-inch ventilated air
space
3"
½” thick insulation board
***
with one-inch ventilated air
space
* All clearances measured from outer surface of
equipment to combustible surface, not to the
protection used.
** Apply to combustible surface unless otherwise
noted. Cover all surfaces as specied in Table and
Figure25. icknesses are minimum.
*** Factory-fabricated board made of non-
combustible materials, normally bers, having
thermal conductivity in range of one (Btu-inch)/
(hr./sq. ./°F) or less.
+ Mineral wool batts (blanket or board), having
min. density of 8 lb/3 and a min. melting point of
1500°F.
Other dimensions available. Refer to NFPA-31.
Close clearance installation (continued)
Figure 25 Flue pipe clearances Figure 26 Back vent clearances
Figure 27 Top vent clearances
Table 6 Protection required for clearances
less than 6 inches from double-wall
vent pipe*
Combustible surface
Protection
Type "L"
double-wall
vent pipe
6"
A
6"
24" For servicing
or min. 2" For close
clearances
Combustible
surface
Combustible
surface
A
A
2"
Note: 2" min. on sides
Combustible
surface
Combustible
surface
A
A
Note: 2" min. on sides
2"
2"
24" For
servicing
or min. 2"
For close
clearances