50
5.
If the flame is partly luminous, the electrode tip should extend only to the edge of the flame. It is
not necessary to maintain absolutely uninterrupted contact with the flame.
6.
It is preferable to angle the rod downward to minimize the effect of sagging and to prevent it
from coming in contact with any object.
7.
An adequate grounding surface for the flame must be provided. The grounding surface in actual
contact with the flame must be at least four times greater than the area of the portion of the flame
rod in contact with the flame. It is essential to adjust the flame rod and ground area ratio to pro-
vide a maximum signal reading.
NOTE: Interference from the ignition spark can alter the true signal reading by adding to, or sub-
tracting from it. This trend sometimes may be reversed by interchanging the primary wires (line volt-
age) to the ignition transformer. This interference can also be reduced by the addition of grounded
shielding between the flame rod and ignition spark.
8.
Proven types of flame grounding adapters, as shown below, may be used to provide adequate
grounding surface. High temperature stainless steel should be used to minimized the effect of
metal oxidation. This assembly may be welded directly over the pilot or main burner nozzle.
MAINTENANCE
Type 48PT2 Infrared and Type UV1, UV2, 45UV5 Ultraviolet an~ 45CM1 Photoelectric Scanners
The viewing area of the scanner must be kept clean. Even a small amount of contamination will
reduce the flame signal reaching the detector by a measurable amount. Wipe the viewing area rou-
tinely using a soft cloth dampened with concentrated detergent.
— Type 48PT2 Scanners include a replaceable #4-263-1 Firetron cell.
— Type 45CM1 Scanners include a replaceable #4-230 Phototube #922.
— Type 45UV5 Scanners include a replaceable #4-314-1 UV tube.
Type 69ND1 Flame Rod
The flame rod and its insulator should be kept clean by washing routinely with soap and water. Rods
should be routinely replaced as they oxidize.
Flame Signal Strength
Routine observation of the flame signal strength will forewarn any deterioration in the capability of
the flame detector or its application.
Contacts
There are no accessible contacts in the MicroM. Where contacts are used, their design assures long
trouble-free life when the load circuits are maintained within the published load ratings.
Humidity
In areas of high humidity, the control chassis should be removed and placed in a dry atmosphere
when the system is expected to be out of service for an extended period.
BOMB FIN GROUNDING ASSEMBLY
THREADED ROD ASSEMBLY
