Honeywell 7800 Series Manual page 38

RM7800E,G,L,M
CHECKOUT
INITIAL LIGHTOFF CHECK FOR DIRECT
SPARK IGNITION
This check applies to gas and oil burners not using 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 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.
4. Close the master switch and start the system with a call
for heat by raising the setpoint of the operating controller, see
Figs. 24, 25 or 26 for RM7800 sequencing. The program
sequence should start the ten second INITIATE sequence.
5. Let the sequence advance through PREPURGE. Igni-
tion spark should occur after 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. Push the reset button and recycle the program se-
quence through PREPURGE.
9. When PILOT IGN status is displayed , watch that 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 after
POSTPURGE is completed.
11. Check all burner adjustments.
12. Wait about three minutes. Close the master switch,
open the manual fuel shutoff valve(s), and try to lightoff the
burner again. 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 by
the equipment manufacturer, close the manual fuel shutoff
valve(s), and open the master switch.
14. If necessary, repeat steps 11 through 13 to establish the
first stage burner flame. Then proceed to step 15.
15. When the first stage burner flame is established, the
sequence will advance to RUN. Make burner adjustments for
flame stability and input rating. If a second stage is used,
proceed to step 18.
16. Shut down the system by opening the burner switch
or by lowering the set point of the operating controller.
Make sure the burner flame goes out and all automatic fuel
valve(s) close.
17. If used, remove the bypass jumpers from the low fuel
pressure limit and subbase.
18. If a second stage is used, make sure the automatic
second stage fuel valve(s) has opened. Check the lightoff as
follows (otherwise proceed to step 19):
a. Open the manual second stage fuel valve(s).
b. Restart the system by raising the set point of the
operating controller.
c. When the first stage burner flame is established,
watch for the automatic second stage fuel
valve(s) to open. Observe that the second stage
lights off properly.
d. Make burner adjustments for flame stability and
input rating.
e. Shut down the system by lowering the set point of
the operating controller. Make sure the burner
flame goes out and all automatic fuel valve(s) close.
f. Proceed to step 19.
19. Restart the system by closing the burner switch
and/or raising the set point of the operating controller.
Observe that the burner flame is established during
PILOT IGN, within the normal lightoff time specified by
the equipment manufacturer.
20. Measure the flame signal. Continue to check for the
proper signal, see Table 8, through the RUN period. Check
the signal at both high and low firing rate positions and while
modulating. Any pulsating or unsteady readings will require
further attention.
21. 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.
22. Return the system to normal operation.
PILOT TURNDOWN TEST (All Installations Using
A Pilot)
Perform this check on all installations that use a pilot. The
purpose of this test is to verify that the main burner can be lit
by the smallest pilot flame that will hold in the flame amplifier
and energize the FLAME LED. Clean the flame detector(s)
to make sure that it will detect the smallest acceptable pilot
flame. If using AMPLI-CHECK™ or Self-Checking Ampli-
fier and 20 kohm/volt meter, the flame signal will fluctuate
every time the amplifier does a self-check or a shutter check.
NOTE: Low fuel pressure limits, if used, could be open. If so,
bypass them with jumpers during this test.
1. Open the master switch.
2. Close the manual main fuel shutoff valve(s).
3. Connect a manometer (or pressure gauge) to measure
pilot gas pressure during the turndown test.
4. Open the manual pilot shutoff valve(s).
5. Close the master switch and start the system with a
call for heat. Raise the set point of the operating control-
ler. The program sequence should start, and PREPURGE
should begin.
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