Honeywell 7800 Series Manual page 39

6 If the pilot flame is not established in ten seconds,
safety shutdown occurs. Let the sequence complete its
cycle. Consult the equipment operating manual for further
information.
7. 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 RM7888A
from the subbase.
b. On the subbase, jumper terminal 4 to ignition termi-
nal 10.
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-
mendations.
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 termi-
nal 4 (L1) to the pilot terminal 8.
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 jumpers from
terminals 4 to 8 and 4 to 10 of the subbase.
k. Check for adequate bleeding of the fuel line.
l. Reinstall the RM7888A on the subbase and close the
master switch, then return to step 3.
8. 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 sight-
ing to provide a maximum and steady flame signal.
9. Recycle the system to recheck lightoff and pilot flame
signal.
10. Energize Special Functions 2 (terminal 17) and 3 (ter-
minal 19).
11 When the MAIN IGN 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 18.
12. 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).
13. Recycle the system to recheck the lightoff and pilot
flame signal.
14. Smoothly open the manual fuel shutoff valve(s) and
try lightoff again. (The first re attempt may be required to
purge the lines and bring sufficient fuel to the burner.)
15. 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.
16. 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.
17. Repeat steps 12 through 16 to establish the main
burner flame; then proceed to step 18.
18. With the sequence in RUN, make burner adjustments
for flame stability and Btu input rating.
19. Shut down the system by opening the burner switch
or by de-energizing terminal 6. 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.
20. Restart the system by closing the burner switch and/
or energizing terminal 6. Make sure that the pilot is estab-
lished during PILOT IGN. Energize terminals 17 and 19
and make sure that the main burner flame is established
during MAIN IGN within the normal lightoff time.
21. Measure the flame signal. Continue to check for the
proper signal, see Table 11 through the RUN period. Check
the signal at both High and Low Firing Rate positions and
while modulating.
22. Run the burner through another sequence, observing
the flame signal for:
a. Pilot flame alone (unless using DSI)
b. Pilot and main flame together.
c. Main flame alone. Also observe the time it takes to
light the main flame. Ignition of main flame should
be smooth.
23. Make sure all readings are in the required ranges
before proceeding.
24. Return the system to normal operation.
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 in-
spection. Refer to the appropriate sample block diagram of
field wiring for the ignition transformer and fuel valve(s)
hookup.
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. Complete the normal ready-to-fire checkout of the
fuel supply and equipment as recommended by the equip-
ment manufacturer.
3. Close all manual main fuel shutoff valve(s). Check
that the automatic fuel valve(s) are closed. Make sure fuel is
not entering the combustion chamber.
39
RM7888A
CHECKOUT
65-0175