Dunkirk Excelsior EXB Series Supplemental Instructions page 20

RIELLO 40BF Blocked Vent safety system (BVS) TROUBLESHOOTING
Problem
Test BVS pressure switch contacts
are closed.
Turn off power supply- Remove
control box and jumper terminals #5
and #6. Restore power.
Burner Starts
Model No.
Serial No.
Date Installed
Contractor
Contact
Address
Postal Code
Telephone No.
After Hours No.
OPERATION AND TROUBLESHOOTING
Condition: Thermostat is calling for heat. Burner is not running.
Possible Cause
Contacts closed.
Contacts open
Motor runs.
Motor does not run.
Burner stays in Pre-purge.
Burner continues to purge and
light off with immediate flame
dropout.
Burner locks out after trial for
ignition.
HOMEOWNER'S REFERENCE TABLE
Remedy
Go to step #2.
Verify pressure tubing is connected properly and clear of obstructions.
Verify vent is not obstructed.
Verify combustion air intake is not obstructed.
Replace.
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.
Verify electrical connections.
Check for seized pump, motor, or fan against housing.
Defective motor capacitor.
Thermal overload (Hot motor).
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
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.
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 filter, 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 fire.
Defective control box/ Replace.
P/N 240009355, Rev. C [11/15/2015]