C7962B VISIBLE LIGHT FLAME DETECTOR
The detector and the flame safeguard control must be
connected to earth ground. A convenient method of
accomplishing this is to connect the detector to the flame
safeguard control with a flexible conduit, or ensure a good
ground connection at the mounting bracket.
ADJUSTMENTS AND CHECKOUT
Before welding the C7962B sight pipe in its final location, or
before tightening the C7962B, complete both the adjustments
and checkout tests that follow and any required by the burner
Adjust detector Sighting Position
With the flame detector installed and burners running, adjust
the position of the flame detector for optimum flame signal. The
flame signal will be read in voltage (Vdc).
The R7851B Amplifier used with the 7800 SERIES controls,
has a dc voltage flame signal output.
For the R7851B Amplifier, a volt-ohmmeter with a zero to 5 of
10 Vdc scale and a minimum sensitivity of 1 megohm/volt is
suggested. See Fig. 5.
Fig. 7. Measuring flame signal voltage of
7800 SERIES controls.
Measure the flame signal voltage as illustrated in Fig. 5. Be
careful to connect the positive meter lead to the positive (+)
amplifier jack and the negative meter lead to the negative (-)
amplifier jack for a 7800 SERIES control. If the 7800 SERIES
control has the optional Keyboard Display Module (KDM), a
zero to five Vdc reading will be displayed on the KDM.
Move the flame detector and sight pipe (if not permanently
attached to the burner/boiler) to view the flame from various
positions. Allow a few seconds for the meter reading to
stabilize. A maximum steady voltage reading is desirable. The
flame signal must be above the minimum acceptable level for
the flame safeguard control and associated amplifier.
Measure the flame signal for the pilot flame alone, the main
burner flame alone, and both together (unless monitoring pilot
only when using an intermittent pilot or supervising the main
flame only when using direct spark ignition). Also, measure the
flame signal at low and high firing rates and while modulating
With the flame detector in its final position, all flame signals
must be steady with a voltage value as indicated for the device.
If the minimum signal cannot be obtained or is unstable, refer
to the Troubleshooting section.
Pilot Turndown Test
If the detector is used to prove a pilot flame before the main
fuel valve can be opened, perform a Pilot Turndown Test.
Follow the procedures in both the instructions for the
appropriate flame safeguard control and in the burner
Before putting the burner into service, check out the installation
using the procedures in the Checkout section of the
instructions for the appropriate flame safeguard control. After
completing the checkout, run the burner through at least one
complete cycle to verify correct operation.
Electrical Shock Hazard.
Can cause serious injury, death or property
Be extremely careful while troubleshooting the
detector; line voltage is present on some of the
terminals when power is on.
Open the master switch to disconnect power before
removing or installing the detector.
Inadequate Flame Signal
If a satisfactory flame signal cannot be obtained while adjusting
the sighting position of the detector, perform the procedures
indicated in steps 1 through 7, below. If other difficulties are
encountered in the system, refer to Troubleshooting in the
instructions for the appropriate Honeywell flame safeguard
1. Check for proper line voltage. Make sure the master
switch is closed, connections are correct, and power
supply is the correct voltage and frequency.
2. Check the detector wiring for defects, including:
a. incorrect connections.
b. wiring type or size of wire.
c. deteriorated wire.
d. open circuits.
e. short circuits.
leakage paths caused by moisture, soot, or dirt.
3. With the burner running, check the temperature at the
detector. When it exceeds 165°F (74°C):
a. use a heat block (part number 136733).
b. add the additional insulation between the wall of the
combustion chamber and the detector.