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OPERATION — 45UV5 SELF-CHECKING UV SCANNER
Self-checking ultraviolet scanners should be used in applications where burner firing operation is
continuous or where the burner is on for long periods of time without recycling. In addition, ultra-
violet self-checking systems are mandatory in some locations.
The operation of this type of system consists of maintaining the flame scanning capability at all
times while also proving that the ultraviolet tube is firing properly. This is done periodically by
mechanically closing off the sight of the UV tube and checking to make sure that the flame signal
goes away. A shutter assembly in the 45UV5 scanner performs this function. The diagram below
explains the process further.
If the shutter assembly in the scanner fails, the tube is faulty, or there is insufficient power to the
scanner, the MicroM will LOCKOUT and display the following message LOCKOUT CHECK
SCANNER. The ultraviolet tube is replaceable (P/N 4-314-1).
A lockout will result if a minimum signal is detected for three consecutive shutter closed periods.
WIRING - UV SCANNERS
To connect the scanner to the control, the UV1 Scanner is supplied with 36” or 72” of flexible cable.
The 45UV5 is supplied with four 72 inch lead wires. Install them in a suitable length of flexible
armor cable and connect it to the control. A conduit connector is supplied with the scanner. Connect
black wires (shutter) to terminals L1, L2; red wires (UV tube) to terminals S1, S2.
If it is necessary to extend the scanner wiring, the following instructions apply:
Scanner wires should be installed in a separate conduit. The wires from several scanners may be
installed in a common conduit.
1.
Selection of Wire
a.
Wiring: For extended scanner wiring up to 500 feet, 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 and each red wire of the 45UV5. The ends of the shielding must be taped
and not grounded.
b.
Asbestos insulated wire should be avoided.
c.
Multiconductor cable is not recommended without prior factory approval.
2.
High voltage ignition wiring should not be installed in the same conduit with flame detector
wires.
SHUTTER OPEN
SHUTTER CLOSED
3.7 SEC.
0.4 SEC.
TIME
