White Rodgers 668 - Manuel (Page 3)

3
4. If safety lockout problem is of an occasional nature
the following additional check may be made to
insure that flame detector location is not a marginal
one:
a. Disconnect flame detector leads from “F” terminals.
b. Attach a jumper wire to one “F” terminal. Start burner.
Then immediately connect jumper wire to the other “F”
terminal. Burner should continue to run.
c. With burner running, attach flame detector leads to an
accurate ohmmeter. Reading of ohmmeter should be
below 1000 ohms, and preferably as low as 500 ohms.
If indicator of ohmmeter remains steady, readings
up to 2000 ohms should also be acceptable. Gener-
ally, though, the lower the reading, the better the
application, and less likely the chance of a variation
in the burner flame causing a safety lock-out.
TESTING CONT.
d. If resistance of flame detector is over 1000 ohms, it may
not be able to see the burner flame properly. Check
alignment of the flame detector through the hole in the
static pressure disc. Clean this hole if it is blocked by
foreign matter. Check for broken “F” wires.
e. If flame detector alignment is good but resistance is still
high, readjustment of burner flame and/or nozzle re-
placement may be necessary (according to burner
manufacturer’s instructions).
Be sure to remove wire jumper after finishing this
flame detector check.
F142-0006 Cell only (Old Style)
PART No. OF REPLACEMENT PART
NOTE
WARNING !