If there is no voltage at pins 2
and 9, be sure there is both line
and control voltage to the control
board. Check for 24 volts at both
terminals C and X and at
terminals W and C. If there is no
control voltage at these points,
check for 115 volt power to the
control board. If there is 24 volts
at terminals C and X, and W
and C, but not at pins 2 and 9,
replace the control board.
Hot Surface Ignition Units.
►
NOTE: The negative presure
switch contacts must be open
before the IFC will power the
induced draft blower.
If there is no voltage at the
motor, disconnect the six-pin
junction plug from the furnace
control board. Measure voltage
at pins 6 and 4 - 115 volts there
but not at the motor means a
wire break.
If there is no voltage at pins 6
and 4, be sure there is both line
and control voltage to the control
board. Check for 24 volts at
transformer secondary terminals
and at terminals W and C. If
there is no control voltage at
these points check for 115 volt
power to the control board. If
there is 24 volts at the low
voltage terminals, and Wand C,
but not at pins 6 and 4, replace
the control board.
Continuity test - turn power off to
the unit, disconnect the wires
from the induced draft blower
and measure the Ohms at the
motor itself.
The Ohmmeter reading should
be about 11 to 12 Ohms. If the
Ohm reading is infinite, replace
the induced draft blower
assembly.
If the induced draft blower has
been replaced or if there is a low
negative pressure reading at the
pressure switch, check the
gasket between the blower
housing and the heat exchanger.
If the seal leaks, clean the old
gasket from the blower housing
and replace it with a new gasket.
FIGURE 100
STANDING PILOT CONTROL BOARD
FIGURE 101 FIGURE 102
STANDING PILOT 9-PIN PLUG HSI CONTROL 6-PIN PLUG
f• ~-
FIGURE 99
INDUCED DRAFT BLOWER
94
To Next Page
Loading...