RM7890, RM7895 100 Vac
To Eliminate Ignition Interference
1 .
Make sure there is enough ground area.
2 .
Be sure the ignition electrode and the flame rod are on op-
posite sides of the ground area.
3 .
Check for correct spacing on the ignition electrode:
4 .
6,000V systems 1/16 in. to 3/32 in. (1.6 mm to 2.4 mm).
5 .
10,000V systems 1/8 in. (3.2 mm).
6 .
Make sure the leadwires from the flame rod and ignition
electrode are not too close together.
7 .
Replace any deteriorated leadwires.
Flame Signal with Hot Combustion Chamber
(All Installations)
1 .
After all initial start-up tests and burner adjustments are
completed, operate the burner until the combustion cham-
ber is at the maximum expected temperature.
2 .
Observe the equipment manufacturer warmup instruc-
tions.
3 .
Recycle the burner under these hot conditions and mea-
sure the flame signal.
4 .
Check the pilot alone for non-DSI (Direct Spark Ignition)
applications or the main burner flame for DSI applications.
5 .
Check the FFRT of the flame amplifier.
6 .
Lower the setpoint of the operating controller and observe
the time it takes for the burner flame to go out. This should
be within 0.8 or 3 seconds maximum, depending on the
amplifier selected.
7 .
If the flame signal is too low or unsteady, check the flame
detector temperature.
8 .
Relocate the detector if the temperature is too high.
9 .
If the response time is still too slow, replace the Plug-in
Flame Signal Amplifier.
10 .
If the detector is relocated or the amplifier is replaced, re-
peat all required Checkout tests.
Safety Shutdown Tests (All Installations)
Perform these tests at the end of Checkout, after all other
tests are completed. If used, the external alarm should turn
on.
1 .
Press the relay module reset pushbutton to restart the
system.
2 .
Open the Airflow Interlock during PREPURGE, PILOT IGN,
MAIN IGN or RUN period (RM7895).
a .
Safety shutdown occurs if the Airflow ILK Switch Failure
configuration jumper (JR3) is clipped (RM7895).
3 .
Detect flame 240 seconds after entry to STANDBY.
a .
Simulate a flame to cause the flame signal voltage level
to be at least 1.25 Vdc for 30 seconds after the initial 40
second entry into STANDBY (PREPURGE for RM7895).
b .
Safety shutdown occurs.
4 .
Observe that pilot does not ignite.
a .
Close the pilot and main fuel manual shutoff valve(s).
b .
Depress the reset pushbutton.
c .
Start the system.
d .
Automatic pilot valve(s) should be energized but the pi-
lot cannot ignite.
e .
Safety shutdown will occur.
5 .
Observe loss of flame during RUN (if Flame Failure Action
configuration jumper, JR2, is selected for Lockout, see Ta-
bles 6 and 7).
a .
Open the main fuel manual shutoff valve(s) and open
the manual pilot shutoff valve(s).
b .
Depress the reset pushbutton.
c .
Start the system. Startup should be normal and the
main burner should light normally.
d .
After the sequence is in the normal RUN period for at
least ten seconds with the main burner firing, close the
manual main and pilot fuel shutoff valve(s) to extin-
guish the main burner flame.
e .
The flame signal drops below 1.25 Vdc within 0.8 or 3
seconds (depending upon the FFRT of the amplifier) af-
ter the main flame goes out.
f .
Safety shutdown occurs.
IMPORTANT
1 .
If the relay module fails to shut down on any of these
tests, take corrective action (refer to the Troubleshooting
section or RM7890, RM7895 diagnostics) and return to
the beginning of all checkout tests.
2 .
When all Checkout tests are completed, reset all switches
to original states.
TROUBLESHOOTING
RM7890, RM7895 System Diagnostics
Troubleshooting control system equipment failures is easier
with the relay module self-diagnostics and first-out annuncia-
tion through the optional KDM. In addition to an isolated spdt
alarm relay (audible annunciation), the relay module provides
visual annunciation by displaying the ALARM LED.
Self-diagnostics of the relay module enable it to detect and
annunciate both external and internal system problems. Ex-
ternal faults such as flame failures and false flame signals are
annunciated by a lockout of the relay module that energizes
the ALARM LED. Refer to the 7800 SERIES Relay Modules
Checkout and Troubleshooting, form 65-0229 for additional
information.
The relay module provides diagnostic information to aid the
service mechanic to obtain information when troubleshooting
the system. See Table 13.
The optional KDM displays sequence status messages indi-
cating INITIATE, STANDBY, PREPURGE, PILOT IGN, MAIN
IGN and RUN. The selectable messages also provide visual in-
dication, current status and historical status of the equipment
such as Flame Signal, Total Cycles, Total Hours, Fault Histo-
ry and Diagnostic Information. With this information most
problems can be diagnosed without extensive trial and error
testing. Information available in the Diagnostic Information
file includes: Device Type, Device Suffix, Software Revision,
Manufacturing Code, Flame Amplifier Type, Flame Failure
Response Time, Selectable Jumper Configuration Status and
Terminal Status.
32-00216-01
24