Honeywell 7800 Series Product Data page 23

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
recommendations.
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 5 (L1) 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.
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 5-8 or 5-10 of the subbase.
k. Check for adequate bleeding of the fuel line.
l. Reinstall the RM7896 on the subbase and close the
master switch; then 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 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 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
shut-off 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 reattempt 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
shut-off 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.
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.
15. Repeat steps 8 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 set point 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 all automatic fuel valve(s) close.
18. Restart the system by closing the burner switch and/or
raising the set point of the operating controller. Observe
7800 SERIES RM7896A,B,C,D RELAY MODULE
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, see Table 5, 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).
Also observe the time it takes to light the main flame. Ignition
of main flame should be smooth.
21. Return the system to normal operation.
22. Make sure all readings are in the required ranges
before proceeding.
NOTE: Upon 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 for gas and oil burners that do not use a
pilot. It should immediately follow the preliminary inspection.
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 checkout of the fuel supply and
equipment as recommended by the equipment
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.
4. Close the master switch and start the system with a call
for heat by raising the set point of the operating
controller, see Fig. 15, 16 or 18. The primary sequence
should start the ten-second INITIATE sequence.
5. Let the sequence advance through PREPURGE. Ignition
spark should occur after the PREPURGE period. Listen
for the click of the first stage fuel solenoid valve(s).
6. Let the program sequence complete its cycle.
7. Open the manual fuel shutoff valve(s).
8. Reset the Lockout Switch and recycle the primary
sequence through PREPURGE.
9. Watch for the FLAME LED to help determine when the
first stage burner flame is established. If it is
established, proceed to step 15.
10. If the first stage burner flame is not established within
four seconds, or within the normal lightoff time specified
by the equipment manufacturer, close the manual fuel
shutoff valve(s), and open the master switch.
11. Check all burner adjustments.
12. Wait about three minutes. Close the master switch,
open the manual fuel shutoff valve(s), and try again to
lightoff the burner. The first attempt may have been
required to purge the lines and bring sufficient fuel to
the burner.
13. If the first stage burner flame is not established within
four seconds, or within the normal lightoff time specified
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