Honeywell 7800 Series Manual page 28

RM7840E,G,L,M
CHECKOUT
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 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. 17, 18, 19, 20 or RM7840 Sequence of Operation. The
program 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 pushbutton and recycle the program
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 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, and 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 manufac-
turer.
20. Measure the flame signal. Continue to check for the
proper signal, see Table 6, 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 INSTALLA-
TIONS 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 Amplifier 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 mea-
sure 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.
6. When the PILOT IGN begins, set the Run/Test
Switch to TEST position to stop the sequence. The
FLAME LED will come on when the pilot ignites.
NOTE: If the sequence does not stop, reset the system and
make sure you set the Run/Test Switch to TEST within
the first eight seconds of the PILOT IGN sequence.
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