39
®
MAINTENANCE
Periodically, the spark electrode should be inspected for proper gapping and cracked ceramics. At
ignition time, the high energy from the ignition transformer will attempt to conduct to the point of
least resistance and with an improper spark gap, where the conduction takes place will no longer be
controlled.
The VA rating of the control transformer must be sized to handle the inrush currents of the pilot sole-
noid and ignition transformer at PTFI and then the inrush currents of the main fuel valve assembly at
MTFI time.
Inspect neatness of wiring in junction boxes and cabinets. It is best to have connections short and
direct and also not having wires bunched up and tied off. Also, connections should be periodically
inspected for tightness and corrosion.
INSTALLATION - UV SCANNERS
Where possible, obtain the burner manufacturer’s instructions for mounting the scanner. This infor-
mation is available for most standard burners. The scanner mounting should comply with the follow-
ing general instructions:
1.
Position the UV1, UV2 or UV90 Scanner within 30 inches of the flame to be monitored; the
45UV5 within 72 inches, closer if possible.
2.
Select a scanner location that will remain within the ambient temperature limits of the UV Scan-
ner. If cooling is required, use an insulating coupling (Fireye #35-69 for UV1, UV2 Scanners,
#35-127-1 for 45UV5) to reduce conducted heat.
3.
The UVl, UV2, 45UV5 Scanners are designed to seal off the sight pipe up to 1 PSI pressure.
Higher furnace pressures should be sealed off. To seal off positive furnace pressure up to 100
PSI for UV1, UV2 Scanners, install a quartz window coupling (#60-1257) For 45UV5 Scan-
ners, use #60-1199 coupling. Add cooling air to reduce the scanner sight pipe temperature.
4.
Install the scanner on a standard NPT pipe (UV1: 1/2", UV2: 3/8”, 45UV5: 1") whose position
is rigidly fixed. If the scanner mounting pipe sights through the refractory, do not extend it more
than halfway through. Swivel flanges are available if desired (#60-302 for UV1, UV2 Scanners,
#60-1664-3 for 45UV5). The sight pipe must permit an unobstructed view of the pilot and/or
main flame, and both pilot and main flames must completely cover the scanner field of view.
5.
Smoke or unburned combustion gases absorb ultraviolet energy. On installations with negative
pressure combustion chambers, a small hole drilled in the UV1, UV2 sight pipe will assist in
keeping the pipe clean and free from smoke. For positive pressure furnaces, provide clean air to
pressurize the sight pipe, if necessary.
6.
Two UV1, UV2 or UV90 Scanners may be installed on the burner if it is necessary to view two
areas to obtain reliable detection of the flame. They should be wired in parallel. Only one repet-
itive self- checking 45UV5 Scanner may be installed on a burner.
7.
To increase scanner sensitivity with UV1, UV2 Scanners, a quartz lens permits location of the
scanner at twice the normal distance. Use
l
/
2
” x 1
l
/
2
” pipe nipple between UV1 Scanner and the
coupling. Use 3/8” pipe nipple and a
l
/
2
” x
3
/
8
” bushing on UV2 installations.
8.
Request the assistance of any Fireye field office for recommendations of a proper scanner instal-
lation on a non-standard application.
SCANNER MUST HAVE UNOBSTRUCTED
VIEW OF FLAME
NOT THIS
NOT THIS
BUT THIS
FLAME MUST COMPLETELY COVER
SIGHT OPENING
NOT THIS
NOT THIS
BUT THIS
