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SYSTEM CHECKOUT
WARNING
Explosion Hazard.
Can cause serious injury or death.
Do not allow fuel to accumulate in the combustion
chamber for longer than a few seconds without igniting
to prevent danger of forming explosive mixture. Close
manual fuel shutoff valve(s) if flame is not burning at
end of specified time.
WARNING
Electric Shock Hazard.
Can cause serious injury or death.
Use extreme care while testing system. Line voltage is
present on most terminal connections when power is on.
Open master switch before removing or installing R7120 Relay
Module or Keyboard Display Module connector.
Make sure all manual fuel shutoff valves are closed before
starting initial lightoff check and Pilot Turndown tests.
Do not put the system in service until you have satisfactorily
completed all applicable tests in this section and any others
recommended by the original equipment manufacturer.
Limit trial for pilot to ten seconds. Limit the attempt to light
main burner to two seconds after fuel reaches burner nozzle.
Do not exceed manufacturer nominal lightoff time.
IMPORTANT
1. If the system fails to perform properly, note the fault code,
fault message, equipment status, and sequence time on
the display. Then refer to the Troubleshooting section.
2. Repeat all required Checkout tests after all adjust-
ments are made. All tests must be satisfied with the
flame detector(s) in their final position.
Equipment Recommended
S7800A Keyboard Display Module
Volt-ohmmeter (1M ohm/volt minimum sensitivity) with: 0-300
Vac capability. 0-6000 ohm capability. 0-10 Vdc capability.
Preliminary Inspection
Perform the following inspections to avoid common problems.
Make certain that:
1. Wiring connections are correct and all terminal screws
are tight.
2. Flame detector(s) is clean, installed and positioned
properly. Consult the applicable Instructions.
3. Combination of amplifier and flame detector(s) is
correctly used. See the amplifier specifications.
4. Plug-in amplifier and purge card are securely in place.
5. Burner is completely installed and ready to fire; consult
equipment manufacturer instructions. Fuel lines are
purged of air.
6. Combustion chamber and flues are clear of fuel and fuel
vapor.
7. Power is connected to the system disconnect switch
(master switch).
8. Lockout is reset (reset button) only if the Relay Module
is powered.
9. Run/Test Switch (if present) is in RUN position.
10. System is in STANDBY condition. STANDBY message
is displayed in the S7800 Keyboard Display Module.
11. All limits and interlocks are reset.
Flame Signal Measurement
See instructions provided with the amplifier.
Initial Lightoff Checks
Proved Pilot Systems
Perform this check on all installations that use a pilot. It should
immediately follow the preliminary inspection.
NOTE: Low fuel pressure limits, if used, could be open. If so,
bypass them with jumpers during this check.
1. Open the master switch.
2. Make sure that the manual main fuel shutoff valve(s) is
closed. Open the manual pilot shutoff valve. If the pilot
takeoff is downstream from the manual main fuel shutoff
valve(s), slightly open the manual main valve to supply
pilot gas flow. Make sure the main fuel is shut off just
upstream from the burner inlet, or disconnect power
from the automatic main fuel valve(s).
3. Close the master switch and start the system with a call
for heat by raising the setpoint of the operating controller;
see the relay module sequence. The R7120 Relay Mod-
ule should start the INITIATE sequence.
4. Let the sequence advance to PILOT IGN (status is dis-
played on the Keyboard Display Module, if used),
PILOT LED turns on, ignition spark should occur and
the pilot should light. If the pilot ignites, the FLAME LED
is energized. Go to step 7.
5. If the pilot flame is not established in ten seconds (four
seconds if configuration jumper JR1 is clipped), safety
shutdown occurs. Let the sequence complete its cycle.
6. Push the reset pushbutton, and let the system recycle
once. If the pilot still does not ignite, make the following
ignition/pilot adjustments:
a. Open the master switch and remove the Burner
Control Module from the subbase.
b. On the subbase, jumper 1 to the ignition terminal 4;
refer to the appropriate wiring diagram to determine
the proper terminal. Disconnect the leadwire to the
pilot valve if it is connected to the same terminal.
c. Close the master switch to energize only the ignition
transformer.
d. If the ignition spark is not strong and continuous,
open the master switch and adjust the ignition elec-
trode spark gap setting to the manufacturer recom-
mendation.
e. Make sure the ignition electrodes are clean.
f.
Close the master switch and observe the spark.
g. After a continuous spark is obtained, open the mas-
ter switch and add a jumper on the subbase from
terminal L1 power to the pilot terminal 3. Reconnect
the leadwire from the pilot valve if it was discon-
nected in step b.
h. Close the master switch to energize both the ignition
transformer and the pilot valve.
13
R7120D BURNER CONTROL MODULES
66-1196EF—01
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