RM7895A RELAY MODULE
32-00122-01
18
3.
Close the master switch and start the system with a
call for heat by raising the set point of the operating
controller, see Fig. 11 or 13. The primary sequence
should start the ten-second INITIATE sequence.
4.
Let the sequence advance through PREPURGE.
Ignition spark should occur and the pilot should
light. If the pilot ignites, the FLAME LED will be
energized. Proceed to step 7.
5.
If the pilot flame is not established in four or ten
seconds, safety shutdown occurs. Let the sequence
complete its schedule. Consult the equipment
operating manual for further information.
6.
Push the reset push button and let the system recy-
cle once. If the pilot still does not ignite, make the
following ignition/pilot adjustments.
a. Open the master switch and remove the RM7895
from the subbase.
b. On the subbase, jumper terminal 5 to ignition
terminal 8 or 10; refer to the appropriate wiring
diagram to determine the proper terminal.
Disconnect the leadwire to the pilot valve if it is
connected to the same terminal.
c. Close the master switch to energize only the igni-
tion transformer.
d. If the ignition spark is not strong and continuous,
open the master switch and adjust the ignition
electrode spark gap setting to the manufacturer
recommendations.
e. Make sure the ignition electrodes are clean.
f.
Close the master switch and observe the spark.
g. After a continuous spark is obtained, open the
master switch and add a jumper on the subbase
from terminal 5 (L1) to the pilot terminal 8.
Reconnect the leadwire from the pilot valve if it
was disconnected in step b.
h. Close the master switch to energize both the
ignition transformer and the pilot valve.
i.
If the pilot does not ignite and if the ignition
spark is still continuous, adjust the pressure reg-
ulator until a pilot is established.
j.
When the pilot ignites properly and stays ignited,
open the master switch and remove the
jumper(s) from terminals 5-8 or 5-10 of the sub-
base.
k. Check for adequate bleeding of the fuel line.
l.
Reinstall the RM7895 on the subbase and close
the master switch, then return to step 4.
7.
When the pilot ignites, measure the flame signal. If
pilot flame signal is unsteady or approaching the
1.25 Vdc minimum value, adjust the pilot flame size
or detector sighting to provide a maximum and
steady flame signal.
8.
Recycle the system to recheck lightoff and pilot
flame signal.
9.
When the MAIN IGN period is displayed by the MAIN
LED, make sure the automatic main fuel valve is
open; then smoothly open the manual main fuel
shutoff valve(s) and watch for main burner flame
ignition. When the main burner flame is established,
proceed to step 16.
10.
If the main burner flame is not established within
five seconds, or the normal lightoff time specified by
the equipment manufacturer, close the manual main
fuel shutoff valve(s).
11.
Recycle the system to recheck the lightoff and pilot
flame signal.
12.
Smoothly open the manual fuel shutoff valve(s) and
try lightoff again. (The first reattempt may have been
required to purge the lines and bring sufficient fuel
to the burner.)
13.
If the main burner flame is not established within
five seconds or the normal lightoff time specified by
the equipment manufacturer, close the manual main
fuel shutoff valve(s). Check all burner adjustments.
14.
If the main burner flame is not established after two
attempts:
a. Check for improper pilot size.
b. Check for excess combustion air.
c. Check for adequate fuel flow.
d. Check for proper gas supply pressure.
e. Check for proper valve operation.
f.
Check for proper pilot flame positioning.
15.
Repeat steps 8 through 14 to establish the main
burner flame; then proceed to step 16.
16.
With the sequence in RUN, make burner adjust-
ments for flame stability and BTU input ratings.
17.
Shut down the system by opening the burner switch
or by lowering the set point of the operating control-
ler. Make sure the main flame goes out. There may
be a delay due to gas trapped between the valve(s)
and the burner. Make sure all automatic fuel valves
close.
18.
Restart the system by closing the burner switch
and/or raising the set point of the operating control-
ler. Observe that the pilot is established during
PILOT IGN and the main burner flame is established
during MAIN IGN within the normal lightoff time.
19.
Measure the flame signal. Continue to check for the
proper signal, see Table 7, through the RUN period.
20.
Run the burner through another sequence, observ-
ing the flame signal for:
a. Pilot flame alone (unless using direct spark igni-
tion).
b. Pilot and main flame together.
c. Main flame alone (unless monitoring an inter-
mittent pilot).
21.
Also observe the time it takes to light the main flame.
Ignition of the main flame should be smooth.
22.
Return the system to normal operation.
23.
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.
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
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 checkout of the fuel supply
and equipment as recommended by the equipment
manufacturer.
