R7140G,L,M BURNER CONTROL MODULES
66-1153—2
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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 R7140
Relay Module should start a ten-second INITIATE
sequence.
4.
Let the sequence advance to PILOT IGN (status is
displayed 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 push button, 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 R7140
Relay Module from the subbase.
b. On the subbase, jumper L1 to the ignition terminal;
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
electrode spark gap setting to the manufacturer
recommendation.
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
master switch and add a jumper on the subbase
from terminal L1 power to the pilot terminal 5 or 6.
Reconnect the leadwire from the pilot valve if it was
disconnected in step b.
h. Close the master switch to energize both the ignition
transformer and the pilot valve.
i.
If the pilot does not ignite and if the ignition spark is
still continuous, adjust the pressure regulator until a
pilot is established.
j.
When the pilot ignites properly and stays ignited,
open the master switch and remove the jumper(s)
from the terminals of the subbase.
k. Check for adequate bleeding of the fuel line.
l.
Reinstall the R7140 Relay Module on the subbase,
close the master switch, and then return to step 4.
7.
When pilot ignites, measure the flame signal. If the pilot
flame signal is unsteady or approaching the 1.25 Vdc
minimum value, adjust the pilot flame size or detector
sighting to provide a maximum and steady flame signal.
8.
Recycle the system to recheck lightoff and pilot flame
signal.
9.
When the MAIN LED turns on, make sure the automatic
main fuel valve is open; then smoothly open the manual
main fuel shutoff valve(s) and watch for main burner
flame ignition. When the main burner flame is
established, go to step 16.
10.
If the main burner flame is not established within five
seconds or the normal lightoff time as specified by the
equipment manufacturer, close the manual main fuel
shutoff valve(s).
11.
Recycle the system to recheck the lightoff and pilot
flame signal.
12.
Smoothly open the manual fuel shutoff valve(s) and try
lightoff again. (The first re-attempt may have been
required to purge the lines and bring sufficient fuel to the
burner.)
13.
If the main burner flame is not established within five
seconds or the normal lightoff time specified by the
equipment manufacturer, close the manual main fuel
shutoff valves(s). Check all burner adjustments.
14.
If the main burner flame is not established after two
attempts:
a. Check for improper pilot size.
b. Check for excess combustion air at Low Fire.
c. Check for adequate Low Fire fuel flow.
d. Check for proper gas supply pressure.
e. Check for proper valve operation.
f. Check for proper pilot flame positioning.
15.
Repeat steps 8 and 9 to establish the main burner
flame; then go to step 16.
16.
With the sequence in RUN, make burner adjustments
for flame stability and Btu input rating.
17.
Shut down the system by opening the burner switch or
by lowering the setpoint of the operating controller.
Make sure the main flame goes out. There may be a
delay due to gas trapped between the valve(s) and
burner. Make sure all automatic fuel valve(s) close.
18.
Restart the system by closing the burner switch and/or
raising the setpoint of the operating controller. Observe
that the pilot is established during PILOT IGN and the
main burner flame is established during MAIN IGN
within the normal lightoff time.
19.
Measure the flame signal. Continue to check for the
proper signal through the RUN period. Check the signal
at both High and Low Firing Rate positions and while
modulating, if applicable.
20.
Run the burner through another sequence, observing
the flame signal for:
a. Pilot flame alone.
b. Pilot and main flame together.