GMC 1976 ZEO 6083 Maintenance Manual page 770

24G- 8 FURNACE
4. Turn up thermostat and check the number of
seconds it takes to pop reset button . This time should
be between 35 and 60 seconds.
5. Open manual to furnace and hold in reset but-
ton until burner lights . Observe flame through sight
glass view port in plenum . It may take several mi-
nutes for air to purge from gas line .
NOTE:
A rumbling or growling noise is not nor-
mal. Refer to "Primary Air Adjustment" later in
this section.
6. Allow furnace to set (not heating) for at least
5 minutes to cool reset (thermal heating element
TH 1) .
7. After cooling, depress reset button, and check
the number of seconds it takes for the flame rod
(switch) to close, which can be heard by listening for
control relay 3CR to "click" in the control box. The
time must be between 10 to 15 seconds.
WARNING : BEFORE ANY REMOVAL OR DISAS-
SEMBLY PROCEDURES ARE PERFORMED ON
THE FURNACE, BE SURE L.P . GAS IS COM-
PLETELY TURNED OFF AT THE L .P . GAS TANK
AND REMOVE FURNACE FUSE FROM FUSE
BLOCK IN LIVING AREA ELECTRICAL COM-
PARTMENT .
WARNING : DUE TO THE POSSIBILITY OF IN-
JURY ON SHARP SHEET METAL, CARE
SHOULD BETAKEN ANYTIME SERVICE IS PER-
FORMED ON THE FURNACE .
REMOVAL
1 . Be sure
LP
gas is turned off at
LP
tank and
furnace fuse is removed from fuse block in living area
electrical compartment.
2. Disconnect furnace electrical connector (See
figure 1) .
3 . Disconnect
LP
gas supply line from furnace
manual valve (See figure 5) .
4. Disconnect furnace ducts from right side of
furnace .
a. If vehicle is equipped with davo, raise seat
and then disconnect ducts from right side of furnace.
Then remove two mounting bolts (See figure 8).
FURNACE REPLACEMENT
8. Set thermostat to a temperature 5° to 10° above
outside temperature.
9 . After thermostat is satisfied, burner will shut
off and blower will continue to run for several mi-
nutes .
10 . When flame rod (switch) cools to proper tem-
perature, blower will stop .
11 . Open door and windows to cool vehicle.
12 . When vehicle has cooled, thermostat contact
closing with automatically re-light furnace. Allow 2
or 3 cycles of this type .
NOTE:
If a problem occurs while proceeding
through the furnace checkout, refer to "Furnace
Trouble Diagnosis" earlier in this section.
b. If vehicle is equipped with swivel chairs,
remove screws retaining duct panel assembly to floor
and sink module . Carefully raise panels and discon
nect ducts from right-side of furnace. Remove panel
assembly and also two mounting bolts (See figure 8) .
Remove swivel chair.
Figure 8-Location Furnace Mounting Bolts
(Right-Side)