Honeywell RA890G, Manual

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7 60-2035—9
RA890G
OPERATION AND CHECKOUT
Fig. 6—Flame current check.
M8716
W136A
196146 METER
CONNECTOR
PLUG (SUPPLIED
WITH W136)
BLACK
BLACK
RED
RED
FLAME
CURRENT
TEST JACK
RA890
PILOT TURNDOWN TEST
CAUTION
The pilot turndown test should be performed only
by qualified personnel, and the instructions should
be followed carefully.
On systems that prove a pilot before the main fuel valve
can be opened, perform a pilot turndown test to prove that the
main burner can be lighted by the smallest pilot that will hold
in the flame relay. Perform a flame current check before and
after the pilot turndown test.
1. Open the main power switch.
2. Shut off the fuel supply to the main burner only by
closing the manual main burner shutoff cock. Do not shut off
the fuel supply to the pilot valve.
3. Restore power to the relay.
4. Start the system by raising the setpoint of the control-
ler (or pressing the START button). The pilot will light and
pull in the flame relay.
5. Reduce the size of the pilot flame to the turndown
condition by slowly closing the manual valve on the pilot gas
line. At the turndown condition, the pilot will be small
enough to just barely hold in the flame relay (2K).
a. Turn down the pilot until relay 2K drops out.
b. Turn the pilot back up slowly just until relay 2K pulls
back in.
c. Again turn the pilot down slightly, but not enough so
the relay drops out.
If the relay drops out again, simply turn up the pilot and
try again. The closer the pilot is to the dropout condition, the
more conclusive the test will be.
6. Check that the pilot is lit and relay 2K is pulled in.
7. Open the manual main burner shutoff cock. Main
flame should light smoothly within one second. If the burner
does not light within one second, close the shutoff cock and
shut off power to the relay. Proceed to step 9.
8. If the burner lights, repeat step 7 two or three times to
verify smooth lightoff.
9. If the lightoff is unsatisfactory, readjust the flame
detector to require a larger pilot flame to hold in the flame
relay. This usually requires resighting the detector farther
out on the axis of the pilot flame.
CAUTION
If the pilot needs to be adjusted and rechecked,
allow five minutes for the purge of unburned gases
in the firebox before proceeding to the next step.
10. Repeat the entire turndown test until the flame is
established promptly in step 7.
11. Turn up the pilot to full flame at the completion of the
test. Perform a flame current check before leaving the job.
IGNITION SPARK RESPONSE TEST
The flame detection system should not respond to the
ignition spark (no meter movement). To determine flame
detector sensitivity to ignition spark, perform the following
steps:
1. Shut off pilot and main fuel manual valves.
2. Connect a W136 Microammeter and 196146 Test
Cable into the test jack on the RA890G. (See Flame Current
check procedure section.)
3. Raise the controller setpoint. This should energize the
ignition transformer and produce an ignition spark.
4. The W136 Meter should not indicate a signal present.
5. If the meter indicates UV is being detected, resight the
flame detector until the UV signal is eliminated. It may be
necessary to construct a barrier to block the ignition spark
from the detector view. Continue adjusting until the ignition
spark flame signal is less than one-fourth microampere.
NOTE: The Honeywell Q624A Solid State Spark Generator
prevents detection of ignition spark when properly ap-
plied with flame detection systems using C7027, C7035,
or C7044 Minipeeper Ultraviolet Flame Detectors. The
Q624A is for use only with gas pilots.
SAFE SHUTDOWN CHECKS LIMIT ACTION
With the burner operating, lower the high limit setting to
simulate an overheated boiler or furnace. Normal shutdown
should occur. Restore the normal limit setting; the burner
should restart.
FLAME FAILURE RESPONSE TEST
With the burner operating for a period of five minutes,
close the manual fuel valves to simulate a flame failure. The
W136 Meter reading should drop to zero within the flame
response timing of the flame safeguard relay (0.8 to 3 sec-
onds nominal). This action should be followed by safety
switch lockout (15 seconds nominal). After the safety switch
cools, open the manual valves. The burner should restart
when the safety switch is reset.
If the meter reading does not drop to zero within the
allowed time, replace the UV detector and repeat the test.
IMPORTANT: Repeat ALL required checkout tests after
all adjustments are complete. ALL tests must be satis-
fied with the flame detector in its FINAL position.