CB780E/CB784E RELAY MODULES WITH VALVE PROVING
32-00150—03
36
750-234
Preliminary Inspection
1.
Wiring connections are correct and all terminal
screws are tight.
2.
Flame detector(s) is clean, and installed and posi-
tioned properly. Consult the applicable instructions.
3.
Correct combination of amplifier and flame detec-
tor(s) is used. See Table 5 in the Specification sec-
tion.
4.
Plug-in amplifier and purge card are securely in
place.
5.
Burner is completely installed and ready to fire; con-
sult equipment manufacturer instructions. Fuel
lines are purged of air.
6.
Combustion chamber and flues are clear of fuel and
fuel vapor.
7.
Power is connected to the system disconnect switch
(master switch).
8.
Lockout is reset (push in reset button) only if the
Relay Module is powered. See Fig. 2 and 3.
9.
Run/Test switch is in RUN position.
10.
System is in the STANDBY condition. STANDBY mes-
sage is viewable in the VFD.
11.
All limits and interlocks are reset.
Flame Signal Measurement
(Table 13 and Fig. 47)
Measure the flame signal at the appropriate times, as
defined in the following Checkout tests. Read the flame
signal in volts dc at the flame amplifier test jacks “+” and
“Com” or at the Keyboard Display Module.
1.
Use one megohm/volt meter with a 0 to 10 Vdc
capability.
2.
Set the one megohm/volt meter to the 0 to 10 Vdc
range.
3.
Insert the positive (red) probe into the + jack of the
flame amplifier. Insert the negative (black) probe
into the (Com) jack of the flame amplifier; see
4.
Allow a few seconds for the meter reading to stabi-
lize.
5.
If using AMPLI-CHECK™ or shutter check amplifiers,
read the average stable voltage, disregarding the
peaks and valleys caused by the self-checking oper-
ation.
6.
The meter reading must be as specified in Table 8
after all tests are completed and all adjustments are
made.
As an option, the flame signal can be checked by using the
Keyboard Display Module.
If the signal is unstable or less than the minimum
acceptable voltage, check flame detector installation and
circuitry.
1.
Check the supply voltages at terminals 4 (L1) and L2
(N). Make sure the master switch is closed, connec-
tions are correct, and the power supply is of the cor-
rect voltage, frequency and is sinusoidal.
2.
Check the detector wiring for defects including:
a. Incorrect connections.
b. Wrong type of wire.
c. Open circuits.
d. Deteriorated wire.
e. Short circuits.
f.
Leakage paths caused by moisture, soot or accu-
mulated dirt.
a
This minimum or stronger signal should easily be obtained if the detector is correctly installed and positioned to prop-
erly sense the flame. This voltage must be obtained before completing checkout.
b
The flame detector shutter and amplifier are tested one-half second every five seconds. Series 4 (or greater) amplifiers
pulse the shutter when the flame signal reaches 1.5 Vdc. Expected flame signal on Series 4 (or greater) amplifiers will
vary between 0.8 Vdc and 2.4 Vdc.
c
This flame amplifier is AMPLI-CHECK™ type. The flame signal amplifier circuitry is tested 1/2 second every five seconds
during burner operation and shuts down the burner if the amplifier fails.
Table 13. Flame Signal.
Flame Detector
Flame Signal Amplifier
Minimum Acceptable
Steady dc Voltage
a
Maximum Expected
dc Voltage
817-1121
833-2741
b
1.25 Vdc
5.0 Vdc at Keyboard Display
Module
or
5.0 Vdc at one megohm/volt
meter.
817-1742
833-2722 or
833-2723
c
817-4133
833-3495 or
833-3496
c
817-1743
833-2724
