Honeywell 7800 Series Manual page 24

RM7885A
CHECKOUT
from the burner inlet, or disconnect power from the automatic
main fuel valve(s).
3. Close the master switch. Allow ten seconds for the
RM7885A to complete the INITIATE Test. Start the system
by pushing the Start Switch, see Fig. 17, or RM7885A
sequence. Ignition should occur and the RM7885 will turn on
the PILOT LED and the pilot valve after a two-second delay
for the RM7885 to complete the Safe-Start Check. The
FLAME LED will be energized when the pilot flame is
proven. The MAIN LED will be turned on and the ALARM
LED and the Alarm output (terminal no. 3) will be turned off.
Proceed to step 5.
If the pilot does not light in ten seconds, release the Start
Switch. Allow time for purging the unburnedfuel from the
combustion chamber before pressing the Start Switch for an
additional ten seconds.
4. If the pilot flame is not established on the second try,
make the following ignition/pilot adjustments or consult the
equipment operating manual for further information:
a. Open the master switch and remove the RM7885A
from the subbase.
b. Close the master switch and push the Start Switch to
energize only the ignition transformer.
c. If the ignition spark is not strong and continuous,
release the Start Switch, open the master switch, and
adjust the ignition electrode spark gap setting to the
manufacturer recommendations.
d. Make sure the ignition electrodes are clean.
e. Close the master switch, press the Start Switch, and
observe the spark.
f. After a continuous spark is obtained, release the Start
Switch and open the master switch. Add a jumper from
the subbase terminal 10 to the pilot terminal 8.
g. Close the master switch and press the Start Switch to
energize both the ignition transformer and the pilot
valve.
h. If the pilot does not ignite and if the ignition spark is still
continuous, adjust the pressure regulator until a pilot is
established.
i. When the pilot ignites properly and stays ignited,
release the Start Switch, open the master switch, and
remove the jumper from terminals 8 through 10 of the
subbase.
j. Check for adequate bleeding of the fuel line.
k. Reinstall the RM7885A on the subbase, close the
master switch, and repeat step 3.
5. When the pilot ignites, release the Start Switch and
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.
6. Press the Stop Switch. Restart the system to recheck
lightoff and the pilot flame signal.
7. When the MAIN LED is energized, 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 13.
8. If the main burner flame is not established within five
seconds or the normal lightoff time specified by the equip-
ment manufacturer, close the manual main fuel shutoff
valve(s).
9. Let the RM7885A run with the pilot only for a couple
minutes to allow time for purging unburned fuel from the
combustion chamber. 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.)
10. If the main burner flame is not established within five
seconds or the normal lightoff time specified by the equip-
ment manufacturer, close the manual main fuel shutoff
valves(s). Check all burner adjustments.
11. 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 adequate fuel flow.
d. Check for proper gas supply pressure.
e. Check for proper valve operation.
f. Check for proper pilot flame positioning.
12. Repeat steps 6 and 7 to establish the main burner flame;
then proceed to step 13.
13. With the sequence in RUN, make burner adjustments
for flame stability and BTU input rating.
14. Shut down the system by pressing the Stop Switch.
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
all automatic fuel valves close.
15. Restart the system by pressing the Start Switch Ob-
serve that the pilot and main burners light properly. Lightoff
should occur within the time specified by the equipment
manufacturer.
16. Measure the flame signal. Continue to check for the
proper signal through the RUN period, see Table 5.
17. Run the burner through another sequence, observing
the flame signal for:
a. Pilot flame alone (unless using direct spark igni-
tion).
b. Pilot and main flame together.
c. Main flame alone (unless monitoring an intermit-
tent pilot).
Also observe the time it takes to light the main
flame. Ignition of main flame should be smooth.
18. Return the system to normal operation.
19. Make sure all readings are in the required ranges before
proceeding.
NOTE: After completing these tests, open the master switch
and remove all test jumpers from the subbase terminals,
limits/controls or switches.
INITIAL LIGHTOFF CHECK FOR DIRECT
SPARK IGNITION
This check applies to gas and oil burners that do not use a
pilot. It should immediately follow the preliminary inspec-
tion. Refer to the appropriate sample block diagram of field
wiring for the ignition transformer and fuel valve(s) hookup.
NOTE: These steps may require two people, one to open the
manual valve(s) and one to watch for iginition.
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