Honeywell RM7824A Product Data page 16

7800 SERIES RM7824A RELAY MODULE
4. With the burner running, check the temperature at the
detector. If it exceeds the detector maximum rated
temperature:
a. Add a heat block to stop conducted heat traveling
up the sight pipe.
b. Add a shield or screen to reflect radiated heat.
c. Add cooling (refer to sight pipe ventilation in the
detector instructions).
5. Make sure that the flame adjustment is not too lean.
6. Make sure that the detector is properly sighting the
flame.
7. If necessary, resight or reposition the detector.
Initial Lightoff Check for Proved Pilot.
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 Fig. 12 or RM7824A sequence). The
primary sequence should start the SAFE-START
CHECK sequence.
4. Let the sequence advance through STANDBY and
SAFE-START CHECK. Ignition spark should occur and
the pilot should light. If the pilot ignites, the FLAME LED
will be energized. Proceed to step 7.
5. If the pilot flame is not established in four or ten
seconds, safety shutdown occurs. Let the sequence
complete its cycle. Consult the equipment operating
manual for further information.
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 RM7824A
from the subbase.
b. On the subbase, jumper terminal 3 to ignition
terminal 8 or 10; refer to the appropriate subbase
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 3 to the pilot terminal 8. 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.
65-0155—2
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 terminals 3 to 8 or 3 to 10 of the subbase.
k. Check for adequate bleeding of the fuel line.
l. Reinstall the RM7824A on the subbase and close
the master switch.
m. Return to step 4.
7. When the 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 RUN period is displayed by the MAIN LED,
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, proceed to step 16.
10. 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 valve(s).
11. Recycle the system to recheck lightoff and pilot flame
signal.
12. Let the RM7824A recycle to the RUN period. Smoothly
open the manual fuel shutoff valve(s) and try lightoff
again. (The first 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 valve(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.
c. Check for inadequate 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 10 through 14 to establish the main
burner flame, then proceed 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 the
burner. Make sure the automatic fuel valve(s) closes.
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 IGNITION and
the main burner flame is established during RUN within
the normal lightoff time.
19. Measure the flame signal. Continue to check for the
proper signal, see Table 6, through the RUN period.
20. Run the burner through another sequence, observing
the flame signal for:
a. Pilot flame alone (unless using direct spark ignition).
b. Pilot and main flame together.
c. Main flame alone (unless monitoring an intermittent
pilot).
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