45
COMMUNICATIONS
When interfacing Fireye controls to a communication system, be it an E500, PLC or other micropro-
cessor based device, ferrite cores should also be utilized. Proper twisted shielded pair cable must be
utilized. In a multi-drop system, the shields should be tied together within a cabinet and not to any
ground point. The shield at the source end of the cable of the multi-drop connection can then be ter-
minated to ground. Source end is defined as the originating end of the communication system
Care must be taken not to route communication cables in close proximity to any starter motor con-
tactors located in the control panel or across any high voltage ignition wires. Refer to Fireye bulletin
E8002 for proper installation.
SCANNERS
The armored cable supplied with the Ultra-Violet and Infrared scanners should be connected to
equipment by means of a good mechanical connection such as a conduit fitting. It may be necessary
to utilize heat insulator (P/N 35-69) to isolate the sensing end of the scanner from boiler ground.
Care must be taken not to route the scanner cable across the high voltage ignition cable. The high
energy ignition cable should be checked periodically for cracking, connections and aging.
In applications using flame rod units and the MERT amplifier, it may be beneficial to route a separate
return wire from the S1 terminal to the flame rod assembly. This will minimize the effects of tran-
sient currents flowing into the MicroM.
In all cases, scanner wires should be routed in separate conduit and not joined with any high voltage
AC or ignition cables.
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 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 P/N 35-69 for UV1, UV2 Scan-
ners, P/N 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 Scanners,
use #60-1100 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,
