Manual

19
Riello 40BF blocked vent safety (BVS) Operation
External Action Appliance Response
Thermostat calls for heat.
• Burner enters pre-purge.
• After pre-purge, oil valve is energized and burner lights off .
• Burner operates in run mode.
• Normally closed pressure switch monitors for vent or combustion air intake blockage.
Call for heat is satisfi ed.
• Oil valve circuit is de-energized and valve shuts off .
• Burner motor runs for duration of burner motor-off delay.
• Burner motor turns off .
Pressure switch contacts open and
cause burner to re-cycle.
1. Check for vent blockage.
2. Check for combustion air intake blockage.
3. Ensure pressure tubes are connected properly and clear of obstructions.
4. Check burner set up.
RIELLO 40BF BURNER TROUBLESHOOTING
Condition: Thermostat is calling for heat. Burner is not running.
Problem Possible Cause Remedy
Reset control box.
Burner starts. Go to step #3
Burner does not start Go to step #1
1. Test for 120 Vac supply at sub-base be-
tween L (P) & N or terminals #3 and #5.
120 Vac present. Go to step #2
No voltage
• Check system fuse, breaker or ensure service switch is ON.
• Verify all limits are closed.
• If using switching relay, verify 24 Vac at T-T.
• Verify BVS pressure switch is closed.
2. Turn off power supply- Remove control
box and jumper terminals #5 and #6.
Restore power.
Motor runs.
• Verify reduced voltage (42-52 Vac) between terminals #3 and #7.
• Ensure good contact between control box spades and sub-base terminals.
• Defective control box/ Replace.
Motor does not run.
• Verify electrical connections.
• Check for seized pump, motor, or fan against housing.
• Defective motor capacitor.
• Thermal overload (Hot motor).
3. Burner Starts
Burner stays in Pre-purge.
• Faulty CAD cell or seeing light before trial for ignition.
• Coil wires on terminals #1 and #2 or #1 and #8 reversed.
• Open coil circuit; terminals #2 and #8.
• Open coil circuit; terminal #1
• Defective 42-52 Vac supply, terminals #3 and #7.
• Defective control box/ Replace
Burner continues to purge and
light off with immediate fl ame
dropout.
• Metal yoke for coil missing.
• Coil wire #2 and #8 reversed.
• Low resistance of coil holding circuit, terminals #1 and #2, (1350 ohms ± 10%).
• Verify BVS pressure switch is remaining closed upon light off .
Burner locks out after trial for
ignition.
• Low resistance or no contact on starting circuit of coil, terminals #2 and #8. (1.3-
ohm ± %)
• No oil supply- tank empty, valve closed, dirty fi lter, damaged supply lines.
• Defective or dirty oil valve stem, nozzle, or pump strainer.
• Broken pump drive key, defective pump or no oil pressure.
• Ignition electrodes shorted, cracked porcelain.
• Burner motor not up to speed.
• Excessive draft over fi re.
• Defective control box/ Replace.
4. Burner Runs, post purge successful.
Aquastat Shows Error EE4.
Some Aquastats limit post
purge time to 1 minute. Error
unique to early models of
L7248.
• Reset Post purge timer on Fan Timer Board to 45 seconds.
OPERATION AND TROUBLESHOOTING