Daikin FC Series Installation And Maintenance Manual page 26

In addition, a Keyboard Display Module is available and is a valuable aid for indicating flame signal DC volts, fault messages,
sequence status, etc . Refer to
Some of the steps listed in this troubleshooting chart will be unnecessary if a Keyboard Display Module is used, as that module will
pinpoint many problems .
Voltage checks can be accomplished without removing the Flame Safeguard by removing the Electrical Access Slot Covers on the
side of the sub-base and then using those electrical access slots .
Table 6: Troubleshooting Chart
Burner Motor Does Not Run (After 10 Second "Initiate" Period And With Switch At Auto):
1 .1 Power LED is
Power is not getting to burner .
OFF .
Burner power comes from the main control panel which has a main disconnect switch, a stepdown
transformer with primary winding fuses, a 120V secondary winding fuse, and an on-off service switch. If
1 .2 Entire unit seems any of these were open, the burner as well as the supply fan would be inoperative . The control system
also has firestat type temperature sensors which will shut down the entire unit if supply or return air
to be OFF .
temperatures exceed set points. On some control systems, the firestats only lock out the supply and
return fans . Check main control schematic, as these would not be burner problems .
a. Check the manual reset limit control located between the filters and the supply fan and reset if
1 .3 Supply fan will
operate .
b . Check that the control system has energized relay R20 located in the main control panel .
1 .4 Power LED is ON . Push the reset button on the flame safeguard.
a . Check
b . Push the reset button on the burner motor .
1 .5 Resetting flame c. Remove the left side electrical access cover on the flame safeguard sub-base and test for line
safeguard
does not start
motor after
the 10 second
d . IF VOLTAGE IS ZERO: The power is being interrupted by the limit control, the manual reset high or
"Initiate" period is
completed .
e . If voltage is satisfactory at terminals 6 and L2 and terminal 4 does not become energized after 10
Burner Motor Runs, But . . .
2 .1 Burner motor runs
a . Check
continuously, but
burner does not
b . The air switch sensing tube is not in the blower housing and sensing pressure .
start (pilot LED)
does not come on c. The air switch or its wiring is defective. 120 volts should appear between terminals 7 and L2 if airflow
after 30 (60 or 90)
seconds .
a . Check
b . If the PILOT LED did not come on for the 10 seconds before shutdown check for voltage between
2 .2 Burner motor
terminal 10 and L2 during the final 10 seconds before control locks out. If zero voltage, replace the
starts when the
RM7897A .
reset button on
RM7897A is c. If the PILOT LED did come on for 10 seconds before shutdown the pilot flame is not igniting or is not
pressed . The being detected by the flame safeguard. Check that the manual gas valves are open.
motor runs for
d. Check the flame safeguard with a flame simulator.
40 (70, 100)
seconds and then
the burner shuts
down and requires
manual resetting .
IM 684-6 • ROOFTOP SYSTEMS
Flame Safeguard on page 23
required .
Table 7 . The LED code may diagnose the problem .
(Note: If motor is hot and probably tripped, it has to cool sufficiently before it can be reset.)
voltage at terminal 4 and L2 . If powered, the problem is with the burner motor or its associated
controls . On Models 1100-2000, terminal 4 only controls a contactor and burner motor power comes
from its own circuit breaker . If terminal 4 is dead, check for power to terminals 6 and L2 .
auto reset low gas pressure switches (if included), the low fire end switch on the modulating operator
(if included), or relay contact in the main control system . Consult the schematic and determine the
interruption .
seconds, and pressing the safety reset button has no effect, replace the RM7897A.
Table 7 . The LED code may diagnose the problem .
switch contacts are made .
Table 7 . The LED code may diagnose the problem .
1 . Close the main gas test cock .
2. Plug the flame simulator into the flame safeguard.
3 . When the pilot indicator light comes on, touch the simulator G post to ground . If the FLAME LED
now comes on the flame safeguard is working, but it is not receiving an adequate flame signal. If
the FLAME LED did not come on replace the R7847A amplifier or/and the RM7897A.
for additional information on the Keyboard Display Module .
26
Troubleshooting
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