Honeywell 7800 SERIES Manual page 22

RM7890A,B,C
CHECKOUT
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 inspec-
tion. 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. 13 or RM7890 sequencing. The primary sequence
should start with the SAFE-START CHECK sequence.
5. Let the sequence advance through STANDBY and
SAFE-START CHECK to Ignition Trial. Ignition spark
should occur. 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 STANDBY and SAFE-START CHECK.
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 light
off 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 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 make sure 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:
65-0126—2
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.
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 5, through the RUN period. 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/voltmeter, 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 by raising the set point of the operating controller.
The primary sequence should start and PILOT IGNITION
should begin.
6. After the sequence has entered the normal burner run
period, turn the pilot gas pressure down very slowly, reading
the manometer (or gauge) as the pressure drops. Stop imme-
diately when the FLAME LED goes out. Note the pressure at
this point.
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