Honeywell 7800 Series Product Data page 24

7800 SERIES RM7896A,B,C,D RELAY MODULE
by the equipment manufacturer, close the manual fuel
shutoff valve(s) and open the master switch.
14. If necessary, repeat steps 8 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 and check the
light-off 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.
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 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/control 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
20K ohm 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).
65-0193
5. Close the master switch and start the system with a call
for heat . Raise the set point of the operating controller.
The primary sequence should start and PREPURGE
should begin.
NOTE: Intermittent Pilot Models should continue with
step 6. Interrupted Pilot Models should
proceed to step 7.
6. INTERMITTENT PILOT MODELS—After the sequence
has entered the normal burner run period, turn down
pilot gas pressure very slowly, reading the manometer
(or gauge) as the pressure drops. Stop immediately
when the FLAME LED goes out. Note the pressure at
this point.
a. If the Flame Failure Action jumper is not clipped :
allow the RM7896A,B to recycle through
PREPURGE. If the Flame Failure Action jumper is
clipped : push the reset pushbutton and allow the
RM7896A,B to recycle through PREPURGE.
b. As the control attempts to relight the pilot, turn the
pilot gas pressure back up slowly until the FLAME
LED comes on. This step must be completed within
4 or 10 seconds, depending on the selected PFEP,
or lockout will occur.
c. Turn the pilot back down slightly but not enough to
cause the FLAME LED to go out. (Keep the pilot gas
pressure just above the reading noted in step 6
above.)
NOTE: Step d requires two people, one to open the
manual main fuel valve(s) and one to watch
for ignition.
d. With the sequence in the normal burner run mode,
make sure the automatic main fuel valve(s) is open.
Smoothly open the manual main fuel shutoff valve(s)
and watch for main burner lightoff.
e. If the main flame is not established within five sec-
onds or the normal lightoff period specified by the
burner manufacturer, close the manual main fuel
shutoff valve(s) and open the master switch. Return
to step 6. If the burner flame is established in the
normal lightoff period, proceed to step 16.
7. INTERRUPTED PILOT MODELS—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 three or eight
seconds of the PILOT IGN sequence.
IMPORTANT
You have eight seconds or three seconds,
depending on the PFEP selected, to position the
Run/Test Switch in the TEST position to stop the
sequence after the start of the PILOT IGN period.
8. Turn down the pilot pressure very slowly, reading the
manometer (or pressure gauge) because it will drop.
Stop instantly when the FLAME LED goes out. Note the
pressure at the RM7896 flame relay dropout point. The
pilot is at the minimum turndown position. Immediately,
turn up the pilot pressure until the FLAME LED comes
on again.
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