Model 800: 1956 Imperials and earlier
Imperial Home Page -> Repair -> Accessories -> Gas Heater -> Page 6
37. NO HEAT
a. Clogged fuel nozzle.
b. No fuel pressure, or low fuel pressure
c. Ignition failure.
d. Insufficient combustion air.
these causes of failure are listed in the order of probability, it is
advisable to check simple causes first to avoid unnecessary
disassembly of heater. Proceed with the check
With ignition switch on and car engine NOT running, turn heater blower
switch on. The fresh air blower should start immediately. Failure of
this blower indicates a defect in blower switch, fuse, blower, or in
associated wiring. The burner blower motor and pump assembly should
also start when switch is turned on. Failure of this motor to start
can be caused by a defective blower switch. A defective coupling
between motor and fuel pump will cause loss of fuel pressure, even if
motor is running. Check voltage at red terminal of ignition, unit with
a teat light or voltmeter and if voltage is satisfactory, replace
burner blower motor.
both blowers run, check the fuel control valve by removing the white
lead from terminal block on front of heater case. Touch this lead to
terminal and listen carefully for a click as valve opens and closes.
(The temperature control should be in HIGH HEAT position for this
test). The click of valve is rather faint, but can be heard when
engine is not running. If valve fails to click, shut off ignition,
remove four screws from heater cover and lift it out far enough to
install a jumper wire directly between white terminal inside case and
white terminal of the solenoid valve. Disconnect overheat switch wires
from these terminals but leave all other wires connected. Temporarily
replace cover of heater case and turn on ignition. Touch white lead to
terminal on front of case again and check for valve action. If valve
fails to click with overheat switch shorted out, check voltage at
white lead with a test light or meter. If lead is hot, and valve fails
to click with overheat switch shorted out, the fuel valve solenoid
coil is defective and must be replaced.
Do not permit the white
lead to touch ground while making these tests.
If the solenoid valve is operating properly, it will be necessary to
cheek the ignition unit. TURN IGNITION SWITCH OFF. Separate two sections
of ignition cable at the connector. Insert a dual-electrode automotive
type plug in end of ignition unit section of ignition cable and ground
plug to engine block. This plug should be adjusted to a gap of .085
inches. Turn ignition and heater switches on and check the plug for a
hot spark. If there is no spark, the ignition unit is defective and must
sure burner is properly grounded and avoid touching any part of assembly
during this test.
This page last updated April 25, 2001. Send us your feedback, and come join the Imperial Mailing List - Online Car Club