37
®
Scanner Wiring
Care should be taken to see that ignitor cables and scanner cables are routed away from one another
on all installations. These cables, when crossed or run together, may interfere with the proper opera-
tion of the flame safeguard control.
If you are experiencing erratic operation or inappropriate characters on the display during the trial
for ignition period, the cause is likely to be ignitor noise. Check for worn ignitor cable insulation,
broken or cut insulation or loose connectors at the electrode and transformers.
SUGGESTED GROUNDING RULES
The Flame-Monitor system, being microprocessor based, requires a ground system that provides a
zero-voltage reference. The voltage measured from L2 to all other terminals except L1 should be 0
volts.
1.
The most effective ground is to run the ground wire in the same raceway as the hot and neutral
from the main distribution service panel (not intermediate sub-panels) to the burner control
panel and insure that this ground wire is well bonded to the control panel.
2.
The wiring base of the Flame-Monitor must have earth ground providing a connection between
the sub-base and the control panel or the burner.
3.
The earth ground wire must be capable of conducting the current to blow the 20A fuse in event
of an internal short circuit. A number 14 AWG copper conductor is adequate, wide straps or
brackets are preferred rather than lead wires.
4.
The ground path needs to be low impedance (less than 1 ohm) to the equipment frame which in
turn needs a low impedance to earth ground. For a ground path to be low impedance at RF fre-
quencies, the connection must be made with minimum length conductors having maximum sur-
face areas.
5.
All connections should be free of nonconductive coatings and protected against rust.
6.
Utilizing conduit as a means of providing a ground must be avoided.
7.
Installing ground rods at the burner control panel defeats the purpose of a single point ground as
described above and could also present a safety hazard.
MAIN
FLAM
E
REFRACTORY
MAIN
BURNER
PILOT
FLAM
E
SCANNER
PILOT
BURNER
INSUFFICIENT PILOT
MAIN
FLAME
REFRACTORY
MAIN
BURNER
PILOT
FLAME
SCANNER
PILOT
BURNER
MINIMUM PILOT
MAIN
FLAME
REFRACTORY
MAIN
BURNER
PILOT
FLAME
SCANNER
PILOT
BURNER
NORMAL PILOT
