3. Energize power supply and turn on
switches A and B. Manually adjust voltage to 20
and then to 28 volts, and allow blower to run 15 to
30 seconds at each voltage. Blower must run freely.
Overhaul blower if there is evidence of binding or
wear, or if there is any noise which would indicate
rough or defective bearings.
4. With switches A and B still closed, adjust
power supply to 24 volts. Ammeter should read as
indicated in figure 3-10.13. Determine blower speed
with tachometer. Speed must be within indicated
5. Turn off switch B and turn on switch C.
Wait 20 to 30 seconds for blower to slow down. The
blower must run smoothly and steadily, but it is not
necessary to check motor speed or current draw.
6. Turn off switches A and C, and shut off
power. Disconnect blower from test equipment.
(m) If voltage limiter was not tested during
blower overhaul, test it now before reassembly.
Follow procedure described in paragraph
3-35b(1)(d). Voltage limiter may be tested without
removing it from blower housing since flag terminal
is accessible. Voltage limiter is grounded through
(4) Heat exchanger assembly installation (fig.
(a) Connect one end of the ground lead assem-
bly (12) to the heater housing (28), and secure with a
nut (14) and lockwasher (13).
(b) Spread the heater housing assembly and
insert the heat exchanger assembly (15) in the
housing. Install the four screws (34) that secure the
(c) Connect the other end of ground lead
assembly (12) to the heat exchanger and secure with
(5) Flame detector switch installation (fig.
(a) Insert the ceramic rod (fig. 3-10.7) into the
tube. Flip the microswitch back into position and in-
stall the adjusting screw.
(b) Slowly turn in the adjusting screw (fig.
3-10.7) until the switch just clicks, then exactly ½
turn more. Secure the adjustment by sealing the ad-
justing screw with G.E. Glyptal varnish, No. 1201.
(c) Install the flame detector switch (21, fig.
3-10.2) in the heater and tighten the compression
nut (22) on the underside of the switch, making sure
that the switch assembly is positioned crosswise to
the axis of the heater so that the guard can be in-
(d) Connect the wires to the NC and NO) con-
tacts on the switch and secure with the screws (20).
(6) Igniter installation (fig. 3-10.2).
(a) Be sure the seal (35) is seated in the top of
the heater housing (28).
(b) If a new igniter is being installed, connect
the shorter lead to the ground terminal (31) on the
top of the heater. Connect the longer lead to the
ignition control (25).
(c) Install the igniter (9) in the igniter tube (8).
Use a screwdriver with a long, thin blade to press
the element end of the igniter firmly into the igniter
tube to ensure that the igniter is firmly seated.
(d) Press the igniter down and turn it clock-
wise to engage the pin on the top of the igniter with
the slots in the igniter tube. Reinstall the electrical
inlet assembly (36) and secure with the Dzus
(e) Reconnect electrical cable to the heater.
If the igniter requires frequent
replacement, test the operation of the
voltage limiter as described in paragraph
3-35b(1)d. An inoperative voltage limiter
allows surges of high voltage from the
ignition control to damage the igniter and
shorten its life.
(7) Ignition control installation (fig. 3-10.2).
(a) Slide the new ignition control (25) under
the two loosened screws (17), install the remaining
two screws, and tighten all four screws.
(b) Route the ignition control lead through
the bundle of wires and connect it to the flame detec-
tor switch (21). If the fuel control valve (26) was
removed, reinstall it, as below, and bundle the wires
with two cable assembly straps (37) or lacing cord,
one on each side of the fuel control valve mounting
(c) Connect the igniter lead and voltage
limiter lead to the spade terminals on the ignition
(8) Fuel control valve installation (fig. 3-10.2).
(a) Slide the fuel control valve mounting
bracket under one screw (27) and engage the fuel
tube (5) in the outlet elbow on the control valve.
Start the compression nut (6) on the elbow, then in-
stall and tighten the remaining two screws (27).
Tighten the compression nut. Check that all the
loose wires are retained between the fuel control
valve mounting bracket and the heater housing.
(b) Connect leads 3, 5, and 30.
(c) Bundle the wires and secure them with two
cable assembly straps (37) or lacing cord, with one
strap on each side of the control valve mounting
(d) Connect the fuel supply line to the IN port