Dunkirk Excelsior EXB Series - Manual (Page 20)

RIELLO 40BF Blocked Vent safety system (BVS) TROUBLESHOOTING
Condition: Thermostat is calling for heat. Burner is not running.
Problem Possible Cause Remedy
Test BVS pressure switch contacts
are closed.
Contacts closed. Go to step #2.
Contacts open
Verify pressure tubing is connected properly and clear of obstructions.
Verify vent is not obstructed.
Verify combustion air intake is not obstructed.
Replace.
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).
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 oil pressure.
Ignition electrodes shorted, cracked porcelain.
Burner motor not up to speed.
Excessive draft over fi re.
Defective control box/ Replace.
HOMEOWNER’S REFERENCE TABLE
Model No.
Serial No.
Date Installed
Contractor
Contact
Address
Postal Code
Telephone No.
After Hours No.
OPERATION AND TROUBLESHOOTING