CB780/CB784 RELAY MODULES
35 32-00207—01
Diagnostic Information Index
The CB780/CB784 monitors input/output terminals and
can display the status of the terminal at the KDM
(example: Pilot Valve T8 ON<). See Table 5 for a complete
terminal description and number. The display will show
the actual status of the terminal. If voltage is detected at
the terminal, ON is displayed, but if no voltage is detected
at the terminal, OFF is displayed; see Table 5.
Historical Information Index
The CB780/CB784 has nonvolitile memory that allows the
Relay Module to retain Historical Information for the six
most recent lockouts. Each of the six lockout files retains
the cycle when the fault occurred, the hour of operation
when the fault occurred, a fault code, a fault message and
burner status when the fault occurred; see Table 4.
SERVICE NOTE:
Reset CB780/CB784 by pressing the reset pushbutton
on the CB780/CB784, or pressing a remote reset push-
button wired through the the 5-wire connector (833-
2760, ordered separately) on the Keyboard Display
Module or DATA CONTROLBUS MODULE™. A power-up
reset will cause an electrical reset of the CB780/CB784
but will not reset a lockout condition.
SERVICE NOTE:
If the Keyboard Display Module is scrambled, remove
and reinstall the Keyboard Display Module, and reset
the CB780/CB784 Relay Module.
SERVICE NOTE:
Use the access slots on the sides of the Wiring Subbase
to check the terminal voltage of the CB780/CB784.
SERVICE NOTE:
Maximum ambient operating temperature of an 817-
1121 flame sensor, Series 1 through 6 will be reduced
to 125°F because of the duty cycle operation of the
CB780/CB784 Relay Module.
Table 10. Hold and Fault Message Summary.
Fault Number Annunciation Message
Fault 1 *No Purge Card*
Fault 2 *AC Frequen/Noise*
Fault 3 *AC Line Dropout*
Fault 4 *AC Frequency*
Fault 5 *Low Line Voltage*
Fault 6 *Purge Card Error*
Fault 7 *Flame Amplifier*
Fault 8 *Flame Amp/Shutr*
Fault 9 *Flame Detected*
Fault 10 *Preignition ILK*
Fault 11 *Running ILK On*
Fault 12 *Lockout ILK On*
Fault 14 *High Fire Sw.*
Fault 15 *Flame Detected*
Fault 16 *Flame-Out TImer*
Fault 17 *Main Flame Fail*
Fault 18 *Flame Detected*
Fault 19 *Main Flame Ign.*
Fault 20 *Low FIre Sw. Off*
Fault 21 *Running ILK*
Fault 24 *Call Service*
Fault 25 *Call Service*
Fault 28 *Pilot Flame Fail*
Fault 29 *Lockout ILK*
Fault 33 *Preignition ILK*
Fault 35-40 *Call Service*
Fault 41 *Main Valve On*
Fault 42 *Pilot Valve On*
Fault 43 *Ignition On*
Fault 44 *PIlot Valve 2 On*
Falt 45 *Low Fire Sw. Off*
Falut 46 *Flame Amp. Type*
Fault 47 *Jumpers Changed*
Fault 50 *Jumpers Wrong*
Fault 51 *Flame Too Strong*
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