Honeywell C7076A Operating Instructions Manual page 7

– F and G wires (blue and yellow) must be run in their own
conduit, independent of other power-carrying leadwires. More
than one scanner F and G wires can be run in the same
conduit.
– A shielded twisted-pair wire may be substituted for using
conduit for routing the F leadwire (blue). Be advised of the
capacitance per foot of shielded wire effectively reduces the
flame signal at the flame safeguard device. Be sure to ground
the shield to the G terminal at the flame safeguard wiring
subbase.
– The detector power and shutter wires need to be run in their
own conduit, as well, avoiding other electrical noise-carrying
wiring.
– The scanner wires should remain separated 2 inch (51 mm)
minimum from other line voltage wires in the main control panel
to the flame safeguard device.
➔ Installation considerations to be avoided that can influence de-
tector operation and maximum leadwire length.
– Moisture.
– Ignition interference.
– High resistance connections and poor grounds.
– Leadwire capacitance.
– Voltage fluctuations.
– Induced line transients.
– Floating grounds—ground at some voltage above earth
ground.
– No G wire—burner used as ground.
– Detector output less than maximum attainable for the installa-
tion (inadequate sighting).
B
A
F
6
G
5
L1
4
shutter
shutter L2
C7076A1031,
220/240 V AC, 50/60 Hz
2
Wiring 220..240 V AC C7076A to EC78XX wiring sub-base.
1
Power supply. Provide disconnect mains and overload protec-
tion as required.
2
CAUtIon When used with EC7800-series relay modules, to
prevent damage to the shutter mechanism, install a
220/240 V AC to 120 V AC, 10 VA minimal step-down
transformer to drive the shutter.
3
Optional SPST switch for remote sensitivity selection.
External
selector
switch 3
7
Master
switch
L1
8
(HOT)
L2
1
2
F
Q7800
Wiring subbase
22
G
L2
B
F
6
G
5
4 shutter
shutter
C7076A1007,
120 V AC, 50/60Hz
C7076A1015,
100 V AC, 50Hz
Wiring 120 V AC C7076A to RM78XX wiring sub-base.
1
Power supply. Provide disconnect mains and overload protec-
tion as required.
2
Optional SPST switch for remote sensitivity selection.
10.1 Remote system sensitivity
For systems firing more than one fuel, each with a different level of
UV emission, or whose flame patterns change with firing rate, two
sensitivity adjustments are provided. An external selector switch (spst)
is required to choose between the two sensitivity settings. (Refer to
Sensitivity Adjustments in the Adjustments and Checkout section.)
With the external selector switch open, the A sensitivi-
ty control setting will determine the sensitivity of the detector;
with the switch closed, the B setting will determine the sensitivity.
1
For automatic sensitivity selection, the switch may be incorporated
into the fuel selector switch or the firing rate switch.
10.2 Connecting detectors in parallel
Two C7076A flame detectors with the same voltage rating can be
connected in parallel to the same terminals. To avoid exceeding the
rating of the shutter control circuit, do not connect more than two
detectors in parallel.
EN-7
External
selector
switch
2
A
7
Master
switch
L1
8
(HOT)
L2
L1 1
L2
2
F
Q7800
Wiring subbase
22
G
L2
1