Section VllI. COOLANT HEATER (Model LEW 300)
inside the housing and bend igniter ground
6-19. Coolant Heater
wire so that it will fit inside a deep socket.
a. Removal. Remove heater in accordance
(9) Disconnect the copper connecting
strap of the preheat resistor (25) and remove
(10) Disconnect lead of solenoid valve (17)
(1) Compress the clamp (1) of the com-
from temperature control (29).
bustion air hose (2) and disconnect the hose
(11) Loosen the compression nut (22) at
from the heater burner (40).
(2) Remove the hose (2) from the blower
the lower end of the standpipe (21) until the
standpipe will turn freely in the fitting.
(5) by loosening the clamp (3).
(12) Hold the fuel valve (17) firmly and
(3) Disconnect the electrical lead of the
unscrew the standpipe from the valve. Lift the
blower (5) from terminal No. 6 of the terminal
valve off when the threads are clear. Avoid
board (33) .
unnecessary pressure on the solenoid cups of
(4) Loosen the nuts (4) on the studs at
the valve since fuel leakage may result if the
the end of the housing (43). Turn the blower
cups are loosened from the surface of the body.
(5) counterclockwise to disengage the bayonet
(13) Remove the screws (18) from the
slots and pull the entire assembly off the end
flange (19) which surrounds the standpipe
of the heater.
(21). Leave one flange loose on the standpipe
(5) Disconnect the flame detector switch
and remove slotted plate (20) from the inside
leads from terminals 2, 3, 4, 6 and 7 of ter-
the heater housing (43).
minal board (33).
(14) Disconnect lead of the preheat resis-
(6) Back off the compression nut which
tor (25) from terminal No. 7 of the terminal
attaches the flame detector switch (6) to the
end of the burner (4). Pull the flame detector
(15) Remove the compression nut (22) at
switch wires through the grommet (38) in the
the lower end of the standpipe (21) and lift
housing and then pull the switch straight out
out the standpipe, preheat resistor (25), flange
of the burner, being careful not to bend the
(19) and compression nut (22), through the
opening in the heater housing (43).
Caution: This tube contains a quartz
(16) It will usually be necessary to destroy
rod which may be broken by excessive bending
the sleeve (23) on the standpipe to remove the
of the tube.
resistor or compression nut. Always use a new
(7) Remove the cover (8) from the end
sleeve when re-installing the standpipe.
of the housing (43) by loosening the nuts (7)
(17) Disconnect wire from control (29)
and turning the cover in a counterclockwise
and note its position for reassembly.
(18) Remove nut (27) from stud between
(8) Disconnect the ground lead (9) by re-
moving nut (10) and lockwasher (11) from