Honeywell R4795A, Manual, Page: 10 / 16

60-2285—7 10
R4795A
CHECKOUT
CAUTION
Do not manually push in the relays.
4. Check that the pilot is lit and relay 2K is pulled in.
5. Open the manual main burner shutoff cock. Main
flame should light 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 7.
6. If the burner lights, repeat step 5 two or three times to
verify lightoff.
7. If the lightoff is unsatisfactory, readjust the flame
detector to require a larger pilot flame to hold in the flame
relay. This usually requires:
a. Resighting a photocell or UV type detector farther
out on the axis of a pilot flame, or
b. Adjusting a flame rod detector so that a larger mini-
mum pilot is required.
8. Repeat the entire turndown test until the flame is
established promptly in step 5.
9. Turn up the pilot to full flame at the test completion.
HOT REFRACTORY HOLD-IN TEST
(PHOTOCELL OIL INSTALLATIONS ONLY)
If hot refractory holds in the flame relay at the end of the
burner-on cycle, the system cannot restart until the relay
drops out. Check for hot refractory hold-in by observing the
flame relay for immediate dropout at the end of a long
burner-on period. If the relay does not drop out, resight the
photocell so it does not sight the refractory, or decrease
photocell sensitivity using aperture disks or filters.
IGNITION SPARK RESPONSE TEST
(UV DETECTORS)
The flame relay should not respond (pull in) to ignition
spark. To determine flame detector sensitivity to ignition
spark, perform the following test:
1. Shut the pilot and main fuel manual valves.
2. Start the system by raising the controller setpoint or
pressing the START button. This should energize the igni-
tion transformer so spark is produced between the electrode
and ground.
3. Check the flame relay 2K. The relay should not pull in.
The flame signal current should not be more than one-fourth
microampere.
4. If relay 2K does pull in, resight the detector farther out
from the spark, or away from possible reflection. It may be
necessary to construct a barrier to block the ignition spark
from the detector view. Continue adjustments until flame
detector does not respond to the ignition spark.
IMPORTANT: Repeat ALL required checkout tests after all
adjustments are complete. ALL tests must be satisfac-
tory when the flame detector is in its FINAL position.
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 go through a normal prepurge and start.
Using manual reset limits is desirable to prevent the
system from cycling off the high limit and to assure that the
condition that caused the limit action is detected as soon as
possible.
Flame Failure
Let burner operate five minutes; then manually shut off
fuel supply to simulate flame failure. Relay should drop out
and fuel valve(s) close. The system will purge and then lock
out on safety. Let the safety switch cool for one minute;
reopen manual fuel valve, and reset safety switch. Burner
should start.
Power Failure
Let the burner run five minutes. Then simulate power
failure by opening the line switch. All relays should drop out
and the fuel valves should close. After a minimum of five
seconds, close the line switch. The R4795 should go through
a normal cycle.
IMPORTANT: At the completion of all Checkout tests,
make sure that the R4795 is not on safety lockout, that
the pilot is turned up to its normal level, and that all
limit settings are correct. Operate the system through
one normal cycle. Replace cover and securely tighten
thumbscrew.