Field Controls MPL-B Furnace User Manual


 
30318 R4 9/9/2005
27
Table C-3: R7184 TROUBLESHOOTING
Condition: Burner motor does not start when there is a call for heat.
Procedure Status Corrective Action
1. Check that limit switches are
closed and contacts are clean.
N/A N/A
2. Check for line voltage power at
the oil primary control. Voltage
should be 120 Vac between the
black and white lead wires on
the oil primary control.
N/A N/A
3. Check indicator light with burner
off, no call for heat (no flame).
Indicator light is on.
Cad cell is defective, sees external light, or connections have
shorted. Go to step 4.
Indicator light turns off. Eliminate external light source or permanently shield cad cell.
4. Shield cad cell from external
light.
Indicator light stays on.
Replace cad cell with new cad cell and recheck.
If indicator light does not turn off, remove yellow lead wires
from R7184 and recheck.
If indicator light is still on, replace the R7184 control.
If the indicator light turns off, replace cad cell bracket
assembly.
5. Verify that the oil valve is closed
during the “valve on delay”
period by opening view port and
verifying that no flame is present
during the 15-second “valve on
delay”.
Indicator light is on. If flame is present, replace the oil valve.
Burner starts.
Trouble is in thermostat circuit. Check thermostat-wiring
connections.
If connections are clean and tight, check thermostat wires for
continuity.
Disconnect line voltage power and open line switch.
Check all wiring connections.
Tighten any loose connections and recheck.
If burner still doesn't start, replace R7184.
6. Jumper thermostat (T -T)
terminals on R7184
IMPORTANT
First remove one thermostat lead
wire.
Burner does not start.
If burner still doesn't start, check the oil burner motor. It may be
seized or burned out.
Condition: Burner starts then locks out on safety with indicator light flashing at 1/2 second on, 1/2 second off.
Procedure Status Corrective Action
Indicator light stops flashing. Go to Step 8.
7. Reset oil primary control by
pushing in and releasing red
reset button.
Indicator light continues to flash
at 1/2 second on, 1/2 second off
rate.
Verify that the control is not in restricted mode. (See notes at end of
this table.). If not in restricted mode, replace R7184