Product Overview

RM7890; RM7895 100 VAC 7800 SERIES RELAY MODULES
66-1195—01 20
WARNING
Electrical Shock Hazard.
Can cause severe injury, death or property
damage.
Use extreme care while testing the system. Line
voltage is present on most terminal connections when
power is on.
1. Open the master switch before removing or installing
the relay module.
2. Make sure all manual fuel shutoff valve(s) are closed
before starting the initial lightoff check and the Pilot
Turndown tests.
3. Do not put the system into service until you have
satisfactorily completed all applicable tests in this
section and any others required by the equipment
manufacturer.
CAUTION
Equipment Damage Hazard.
Use of improper equipment will cause operational
failure.
Do not replace the RM7890, RM7895 Relay Module
with a lower or higher functioning relay module until
you have made the necessary wiring changes or the
burner will not sequence.
IMPORTANT
1. If the system fails to function properly, refer to 7800
SERIES Relay Modules Checkout and
Troubleshooting, form 65-0229.
2. Repeat all required CHECKOUT tests after all
adjustments are made. All tests must be satisfied
with the flame detector in its final position.
Equipment Recommended
Volt ohmmeter (one megohm/volt minimum sensitivity):
a. 0 to 300 Vac range.
b. 0 to 6000 ohms range.
c. 0 to 10 Vdc range.
Checkout Summary
1. Preliminary inspection, all installations.
2. Flame signal measurement, all installations.
3. Initial lightoff check for proved pilot, all installations
using a pilot.
4. Initial lightoff check for direct spark ignition (DSI) of oil,
all burners using DSI.
5. Pilot turndown test, all installations using a pilot.
6. Hot refractory hold-in test, all installations.
7. Ignition interference test, all installations using flame
rods.
8. Flame signal with hot combustion chamber, all
installations.
9. Safety shutdown tests, all installations.
See Fig. 14 for location of component parts and see Fig. 5 or
6 or Q7800 Specifications, form 65-0084, for terminal
locations.
Preliminary Inspection
When performing the following inspections, check to verify:
1. Wiring connections are correct and all terminal screws
are tight.
2. Flame detector is clean, installed and positioned
properly. (Check the applicable installation instructions.)
3. Correct combination of amplifier and flame detector is
used. See Table 4.
4. Plug-in amplifier is securely in place.
5. Burner is completely installed and ready to fire. (Consult
equipment manufacturer instructions.)
6. Fuel lines are purged of air.
7. Combustion chamber and flues are clear of fuel and fuel
vapors.
8. Power is connected to the system disconnect switch
(master switch).
9. Lockout switch is reset (push in reset pushbutton) only if
the relay module is powered; see Fig. 14.
10. System is in the STANDBY condition and POWER LED
is energized.
11. All limits and interlocks are reset.
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). See Fig. 16 and
Table 12.
Table 12. Flame Signal.
a
This minimum or a stronger signal should be easily obtained if the detector is installed correctly and positioned to properly
sense the flame. This voltage must be obtained before completing checkout.
Minimum Acceptable Steady dc Voltage
a
Maximum Expected dc Voltage
1.25 Vdc
5.0 Vdc at the KDM
or
5.0 Vdc at a one megohm per volt meter.