3
TESTING (cont’d)
Rotate Cell Assembly counter-
clockwise to remove it. To replace
it, insert end through notched open-
ing in bracket and rotate clock-
wise. NOTE: If bracket is ever re-
moved from burner, Cell Assembly
will not fit if bracket is reinstalled
backwards.
TYPE 956 FLAME DETECTORS
OLD STYLE
NEW STYLE
CELL ASSEMBLY
SOCKET
ASSEMBLY
CELL
BRACKET
F063-0485
F063-2006
Cell only (Old Style)
Cell assembly (New Style)
PART No. OF REPLACEMENT PARTS
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, read-
ings up to 2000 ohms should also be acceptable.
Generally, the lower the reading, the better the
application, and less likely the chance of burner
flame variation causing a safety lock-out.
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
replacement may be necessary (according to burner
manufacturer’s instructions).
Be sure to remove wire jumper after finishing this
flame detector check.
NOTE
WARNING
!