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TYPICAL SCANNER INSTALLATIONS
OPERATION — 45UV5 SELF-CHECKING UV SCANNER
Self-checking ultraviolet scanners should be used in applications where burner firing operation is
continuous or where the burner is on for long periods of time without recycling. In addition, ultra-
violet self-checking systems are mandatory in some locations.
The operation of this type of system consists of maintaining the flame scanning capability at all times
while also proving that the ultraviolet tube is firing properly. This is done periodically by mechani-
cally closing off the sight of the UV tube and checking to make sure that the flame signal goes away.
A shutter assembly in the 45UV5 scanner performs this function. The diagram below explains the
process further.
If the shutter assembly in the scanner fails, the tube is faulty, or there is insufficient power to the
scanner, the Flame-Monitor will LOCKOUT and display the following message LOCKOUT
CHECK SCANNER. The ultraviolet tube is replaceable (P/N 4-314-1).
A lockout will result if a minimum signal is detected for three consecutive shutter closed periods.
THE MAXIMUM UV SIGNAL FROM
A FLAME IS FOUND IN THE FIRST
ONE-THIRD OF THE VISIBLE
FLAME TAKEN FROM THE POINT
WHERE THE FLAME BEGINS. THE
SCANNER SIGHT PIPE SHOULD
BE AIMED AT THIS AREA.
DO NOT EXTEND
MORE THAN
HALF-WAY INTO
REFRACTORY
SCANNER
FORCED
CLEAN AIR
(FROM DISCHARGE
OF FAN)
METHODS OF COOLING SCANNER
INSULATING
TUBING
SEALING UNION
FORCED
AIR
EXTEND SIGHTING TUBE
6”(1524) OR 8”(2032)
DO NOT EXTEND MORE THAN
HALF-WAY INTO REFRACTORY
SHUTTER OPEN
SHUTTER CLOSED
3.7 SEC.
0.4 SEC.
TIME
