11
FIGURE 4.
SINGLE BURNER SCANNER SIGHTING
4.
Consideration must be given to burner secondary air rotation, some burners have clockwise
(CW) air rotation and others have counterclockwise (CCW) air rotation. If combustion air enters
the furnace with a rotational movement of sufficient velocity to deflect the ignitor flame in the
direction of rotation, position the scanner 10 to 30 degrees downstream of the ignitor as shown
in Figure 5 and close to the periphery of the burner throat (See Figure 4).
FIGURE 5.
SCANNER LOCATION VS. SECONDARY AIR ROTATION
5.
Having determined the approximate location for the sight pipe, cut a clearance hole for a 2 inch
pipe through the burner plate. Look through the hole. If register vanes interfere with the desired
line of sight, the interfering vane(s) should be trimmed to assure an unrestricted viewing path at
all firing levels as indicated in Figure 6.
Note: Always check with the burner manufacturer before you trim register vanes.
FIGURE 6.
IF POSSIBLE, FLAME SHOULD COMPLETELY COVER SIGHT OPENING
6.
The preferred method for mounting surface mounted scanners requires the use of a swivel
mount, P/N 60-1664-3 (NPT), shown in Figures 7, 8, and 9. Center the swivel mount over the
two inch hole in the burner plate and secure using three hexed cap screws (not provided). Install
the sight pipe on the swivel mount. If a swivel is not used, insert the end of the sight pipe into
the hole, align the hole to the desired viewing angle and tack weld (welding must be adequate to
temporarily support the weight of the installed scanner). The sight pipe should be arranged to
slant downward so that dirt and dust will not collect inside.
CAUTION: Use no more than one foot of one inch diameter sight pipe. Increase the sight
pipe diameter one inch for every additional foot of sight pipe length used to avoid restricting
the scanner’s field of view.
When a satisfactory sighting has been confirmed by operational testing, secure the swivel
mount’s ball position in place by tightening the three hex head cap screws located on the
swivel mount ring.
PRIMARY
COMBUSTION
ZONE
AIR REGISTER
BLADES
SCANNER
LINE OF
SIGHT
BURNER
THROAT
FLAME
ENVELOPE
BURNER
CENTER LINE
BASE
IGNITOR
SCANNER
MAIN
BURNER
CCW ROTATION
IGNITOR
SCANNER
MAIN
CW ROTATION
BURNER
BUT THIS
NOT THIS
NOT THIS
OR THIS
Obstruction
Obstruction
