GMC 1976 ZEO 6083 Maintenance Manual page 778

24G- 1 6
FURNACE
INSTALLATION
1 . Position blower assembly against combustion
chamber. Install six retaining screws (See figure 29) .
2. Connect flue tube to combustion chamber (See
figure 28) .
bly.
3 . Connect combustion air tube to blower assem-
4. Position inner inlet pipe and exhaust outlet
pipe as shown in Figure 26 . Place back plate and
outer inlet pipe against furnace as shown in Figure
25 . Install back plate retaining screws .
5. Install straps to furnace (See figure 24).
6. Install outer casing on furnace (See figure 19).
7. Install wiring access cover (figure 18).
PRIMARY AIR ADJUSTMENT
Access to the burner assembly to adjust primary
air is located at the bottom, right side of the furnace
compartment by removing access cover (figure 11).
4N VEHICLE ADJUSTMENT
NOTE :
To gain access to right side of furnace, if
vehicle is equipped with a davo, squeeze levers
located under center of davo seat and raise seat .
1 . Loosen hex lock nut slightly until burner ad-
justing rod can be turned with a screwdriver (See
figure 31).
2. Start furnace and watch burner through sight
glass view port in plenum (See figure 5) . Decrease
primary air to give a slightly yellow flame with green
cones. The cones are formed at each of the ports in
the burner . Then increase air slowly until the yellow
disappears and the cones become sharply defined as
blue .
NOTE: The total adjustment available, from one
extreme to the other, is only about 1/4 turn . Do
not force adjusting rod past the stops .
Figure 30-Blower Assembly
8 . Install furnace in vehicle. See "Furnace Re-
placement" earlier in this section.
4 . Recheck flame to see that it is still properly
adjusted .
Hold the adjusting rod in place and tighten the
hex nut.
Figure 31-Furnace Primary Air Adjustment