GENERAL
Equipment rrequired:
Digital Volt/Ohm Meter
Explanation:
All electrical components within the heater may be tested to
determine if voltage is being supplied to, or sent through the
component. Familiarizing yourself on how to check voltage
is critical since it will help you determine if a component is
working properly, plus, it will shorten the amount of time
used should troubleshooting equipment problems occur.
Attention
The ignition control module will not operate without 24 V.A.C.
supplied from the transformer.
Before we look at basic procedures in checking voltages at
individual parts, it is good to know which components within
the control system work on a particular voltage. Since the
ignition control module sends and receives voltages
throughout the heater we will review the terminal
designation on both past and present designs of control
modules. Refer to the following illustrations for comparison
of ignition controls and positioning of designators, which in
turn will identify the voltage that each individual component
receives.
Component
Testing
Part #
#120-0
09298
Part #
#120-0
08117
Self-D
Diagnostic C
Control M
Module TTerminal
Designators aand VVoltages
(Part #
#120-0
09298 aand 1
120-0
08117)
IND
120 V.A.C. from module to motor
L1
120 V.A.C. power supply voltage to module
HSI
120 V.A.C. from module to igniter
HSIG
Neutral return for igniter
L2
Neutral of igniter (part #120-09298)
COMM
Neutral of igniter (part #120-08117)
W
24 V.A.C. to module from transformer
PSI
24 V.A.C. from module to air proving switch
FSI
100 V.A.C. from module to flame sensor (black module)
24 V.A.C. from module to flame sensor (white module)
GV
24 V.A.C. from module to high limit and then to gas
control valve
PSO
24 V.A.C. from air proving switch back to module
FSG
Flame sensor ground
C
Control module ground
6.1-1
1
August 1999
Voltage Checks