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FIGURE 3.

2. If combustion air enters the furnace with a rotational movement of sufficient velocity to deflect

pilot flame in direction of rotation, position the scanner 0 to 30 degrees downstream of the pilot

burner and close to the periphery of the throat where the ultraviolet radiation is at a maximum.

(See Figures 2 and 3).

3. Having determined an appropriate location for the sight tube, cut a clearance hole for a 2 inch

pipe through the burner plate. If register vanes interfere with the desired line of sight, the inter-

fering vane(s) should be trimmed to assure an unobstructed viewing path at all firing levels, see

Figure 4.

4. Mount scanner sight pipe by either:

— Centering a Fireye No. 60-1664-3 (NPT) or 60-1664-4 (BSP) swivel mount over the hole

and installing the sight pipe on the swivel mount,

— Inserting the end of the sight pipe into the hole, aligning the pipe to the desired viewing

angle and tack welding. (Welding must be adequate to temporarily support the weight of the

installed scanner). The sight pipe should be arranged to slant downward so that the dirt and

dust will not collect in it.

FIGURE 4.

5. When a satisfactory sighting position has been confirmed by operational test, (see section on

alignment), the sight pipe should either be firmly welded in place or, if the swivel mount is used,

the base position should be secured by tightening the three hex head cap screw located on the

swivel mount ring. In certain older style swivel mounts, tack welding may be required.

6. Excessive flame signal can affect flame discrimination and prevent the control connected to the

scanner from performing properly. To reduce the signal level of the tube, or improve flame dis-

crimination, orifices may be installed to decrease the scanner’s field of view and reduce its sen-

sitivity. Installation of the orifice disk is shown in Figure 6.

7. The scanner viewing window must be kept free of contaminants (oil, smoke, soot, dirt) and the

scanner temperature must not exceed its maximum rating. Both requirements will be satisfied by

continuous injection of purge air.

The scanner mounting may be made with provision for purge air through the 3/8” opening as shown

in Figure 5, Item A or C, or through a 1" tee/wye connection as shown in Figure 5, Item B. Normally

only one of the two connections is provided with purge air and the other is plugged. When a Fireye

union is used as shown in Figure 5, the 1" tee/wye connection is used for the purge air (plug 3/8”

opening).

IGNITOR

SCANNER

MAIN

BURNER

CCW ROTATION

SCANNER LOCATION VS. SECONDARY AIR ROTATION

IGNITOR

SCANNER

MAIN

CW ROTATION

BURNER

BUT THISNOT THIS NOT THIS

FLAME MUST COMPLETELY COVER SIGHT OPENING