7
£
4.
Installation of Extended Scanner Wiring:
— For extended scanner wiring up to 500 feet (150M), and for shorter lengths to reduce signal
loss, use a shielded wire (Belden 8254-RG62 coaxial cable, or equal)
for each scanner wire
of UV1, UV2. The ends of the shielding must be taped and not grounded.
5.
Multiple Scanner Installations:
— The wiring from multiple UV scanners may be installed in a common metallic conduit.
— Multi-conductor cable is not recommended without prior factory approval.
INSTALLATION - 69ND1 FLAME ROD
The 69ND1 flame rod proves a gas pilot flame and/or main gas flame. It is a
spark plug
type unit
consisting of
1
/
2
s
NPT mount, a KANTHAL flame rod, a glazed porcelain insulating rod holder and
a spark plug connector for making electrical connections. The 69ND1 is available in 12
s
(304.8mm),
18
s
(457.2mm) or 24
s
(609.2mm) lengths.
The flame rod may be located to monitor only the gas pilot flame or both the gas pilot and main gas
flames. It is mounted on a
1
/
2
s
NPT coupling.
The following instructions should be observed:
1.
Keep flame rod as short as possible.
2.
Keep flame rod at least
1
/
2
s
(12.7mm)from any refractory.
3.
Flame rod should enter the pilot flame from the side so as to safely prove an adequate pilot
flame under all draft conditions.
4.
If the flame is nonluminous (air and gas mixed before burning), the electrode tip should extend
at least
1
/
2
s
(12.7mm)
into the flame, but not more than halfway through
5.
If the flame is partly luminous, the electrode tip should extend only to the edge of the flame. It is
not necessary to maintain absolutely uninterrupted contact with the flame.
6.
It is preferable to angle the rod downward to minimize the effect of sagging and to prevent it
from coming in contact with any object.
7.
An adequate grounding surface for the flame must be provided. The grounding surface in actual
contact with the flame must be at least four times greater than the area of the portion of the
flame rod in contact with the flame. It is essential to adjust the flame rod and ground area ratio
to provide a minimum signal reading of 6VDC.
Note: Interference from the ignition spark can alter the true signal reading by adding to, or sub-
tracting from it. This trend sometimes may be reversed by interchanging the primary wires (line volt-
age) to the ignition transformer. This interference can also be reduced by the addition of grounded
shielding between the flame rod and ignition spark.
WRONG POSITION
OF ROD
INADEQUATE FLAME
PILOT BURNER
CORRECT POSITION
OF PILOT FLAME
CORRECT
POSITION
OF ROD
