GMC 1976 ZEO 6083 Maintenance Manual page 769

FURNACE
24G- 7
BLOWER DOES NOT COME ON WHEN THERMOSTAT IS CALLING FOR HEAT
The following checkout is given to aid in check-
ing the furnace if it has not been operated for a long
period of time or if a suspected problem is encoun-
tered.
1 . Check LP gas pressure at range/oven using a
water manometer with burners turned on . Details for
checking and adjusting LP gas pressure
is
given in
Section 24F "LP Gas System ." Pressure should be 11
inches of water.
OPERATIONAL CHECKOUT
2. Sol-Aire furnace is designed to operate on a
minimum of 10.2 Volts D.C. If voltage is less than
10.2 volts, then reset button will trip and shut off
furnace. Check voltage at furnace and recharge liv-
ing area battery, if necessary .
3. Shut off gas manual valve at furnace. Depress
reset button .
No. Check to Make Results Go To Problem
1. a. With thermostat calling for heat Furnace turns on. Reset was not set.
press in reset button .
Furnace does not turn on .
#2
2 . a. Check the 10 amp fuse in the
Fuse OK. #3
furnace.
Fuse blown .
#5
3. a . Short across the two thermostat Furnace starts . Defective thermostat or
leads at the control box on furnace . broken wire .
Furnace does not start . #4
4. a. Remove Furnace from vehicle . Blower runs . Defective control circuit .
b . Connect a 12V source across the Blower does not run. Defective blower asm.
#11 and #5 terminals on the control
box.
5 . a. Install a new fuse in the furnace .
Furnace starts and runs. Surge current blew fuse,
Turn the thermostat on. furnace OK.
Fuse immediately blows
#6
again .
6. a. Remove furnace from vehicle.
b. Disconnect the wires from terminals Fuse blows immediately . Defective control box .
#I 1 and # 12 on the control
box.
c. Install a new fuse in the furnace .
d . Connect the furnace to a 12V Fuse does not blow .
#7
source .
e. Short across the thermostat wires.
7 . a. Reconnect the wire to the #12
Fuse blows . Defective ignition pak.
terminal on the control box .
b . Short across the thermostat leads
Fuse does not blow . Defective blower asm.
with the furnace connected to a
12V source .