Honeywell RM7824A Product Data page 15

See Fig. 14 for location of component parts and see Fig. 6 or
Q7800 Specifications for terminal locations.
Preliminary Inspection
Perform the following inspections to avoid common problems.
Make certain that:
1. Wiring connections are correct and all terminal screws
are tight.
2. Flame detector(s) is clean, installed and positioned
properly. Consult the applicable instructions.
3. Correct combination of amplifier and flame detector(s) is
used. See Table 2 in the Specifications section.
Flame Detector
C7024E,F
C7015A
a
This minimum or a stronger signal should be easily obtained if the detector is correctly installed and positioned to properly
sense the flame. This voltage must be obtained before completing checkout.
b
The flame signal amplifier circuitry is tested one-half second every five seconds during burner operation and shuts down the
burner if the amplifier fails (all installations).
c
The amplifier is an AMPLI-CHECK™ type.
Flame Signal Measurement
Measure the flame signal at the appropriate times defined in
the following checkout tests. Read the flame signal volts dc at
the flame amplifier test jacks (+) and (-) (Com).
1. Use a 1M ohm per volt voltmeter with a 0 to 30 Vdc
capability.
2. Set the voltmeter to the 0 to 10 Vdc range.
3. Insert the positive (red) probe into the (+) jack of the
flame amplifier and the negative (black) probe into the
( -) (Com) jack of the flame amplifier (see Fig. 16).
4. Allow a few seconds for the meter reading to stabilize.
5. When using a shutter check amplifier, read the average
stable voltage, disregarding the peaks and valleys
caused by the self-checking program.
6. The meter reading must be as specified in Table 6 after
all tests are completed and all adjustments are made.
As an option, the flame signal can be checked by using the
optional Keyboard Display Module.
If the signal is unstable or less than the minimum acceptable
voltage, check the flame detector installation and circuitry.
Table 6. Flame Signal (See Fig. 17).
Flame Signal Amplifier
b
R7824C
c
R7848A,B
7800 SERIES RM7824A RELAY MODULE
4. Plug-in amplifier is securely in place.
5. Burner is completely installed and ready to fire; consult
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 switch is reset (push in reset pushbutton) only if
the RM7824A is powered. See Fig. 1 and 2.
9. 9.System is in the STANDBY condition. POWER LED is
energized.
10. 10.All limits and interlocks are reset.
Minimum Acceptable Steady
a
dc Voltage
1.25 Vdc
NEGATIVE (-)
METER LEAD
Fig. 17. Flame signal measurement.
1. Check the supply voltages at terminals 3 and L2 (N).
Make sure the master switch is closed, connections are
correct and the power supply voltage is correct.
2. Check the detector wiring for defects including:
a. Deteriorated wire.
b. Incorrect connections.
c. Leakage paths caused by moisture, soot or
accumulated dirt.
d. Open circuits.
e. Short circuits.
f. Wrong wire type.
3. For all optical detectors, clean the detector viewing
window and inside the sight pipe as applicable.
15
Maximum Expected dc
Voltage
5.0 Vdc at the Keyboard
Display Module or 5.0 Vdc at a
1M ohm/volt voltmeter.
POSITIVE (+)
METER LEAD
ONE MEGOHM/VOLT
METER
M7382
65-0155—2