Honeywell 7800 Series Manual page 38

RM7838B
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. These
steps may require two people - one to open the manual
reset safety shutoff valves and one to observe ignition.
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 the Burner Control. See
Figs. 19 and 20, RM7838B sequence. The Alarm will sound
until flame has been detected.
5. Let the RM7838B sequence advance through PURGE.
When "PURGE HOLD: T21" is displayed on the Keyboard
Display Module VFD, press the Start button and the RM7838B
will energize the ignition spark. Listen for the click of the first
stage fuel solenoid valve(s).
6. The RM7838B will lock out for flame failure unless
the flame detector is picking up the ignition spark.
7. Open the manual fuel shutoff valve(s).
8. Press the Reset button on the RM7838B and the pro-
gram will sequence through PURGE.
9. When "PURGE HOLD: T21" is displayed, press the
Start Switch and 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 shut-off
valve(s), and open the Burner Control Switch.
11. Press the reset button and wait about three minutes to
purge the combustion chamber of any unburned fuel. Then
check all burner adjustments.
12. Close the Burner Control 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 shut-off
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, if
Configuration Jumper JR2 is clipped switch the Run/Test
Switch to TEST. Make burner adjustments for flame stability
and input rating. If a second stage is used, make sure the
automatic second stage fuel valve(s) has opened.
65-0120—1
16. Shut down the system pressing the system Stop Switch.
Make sure the burner flame goes out and make sure all
automatic fuel valve(s) close. The RM7838B will initiate a
purge and stop when the purge is complete and display
"PURGE HOLD: T21." An alarm output will be present
when the flame has gone out.
17. If used, remove the bypass jumpers from the low fuel
pressure limit and subbase.
18. If a second stage is used, check the lightoff as follows
(otherwise proceed to step 19).
a. Open the manual second stage fuel valve(s).
b. Restart the system by closing the Burner Control
Switch.
c. After the first stage burner flame is established, open
the Pilot Valve Hold Switch (if used) and close the
Manual Open Valve Switch. (If JR3 is clipped, the
RM7838B will command terminal 9 on and a Manual
Open Valve Switch input (terminal 17) will be
required within 10 seconds.) Watch the automatic
second stage fuel valve(s) to open and observe that
the second stage lights off properly.
d. Make burner adjustments for flame stability and
input rating.
e. Shut down the system by pressing the Stop Switch.
Make sure the burner flame goes out and all auto-
matic fuel valve(s) close.
19. When "PURGE HOLD: T21" appears on the display,
press the Start Switch. Observe that the burner flame is estab-
lished 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 Amplifier and volt/ohmmeter, the flame signal
will fluctuate every time the amplifier does a self-check or a
shutter check.
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