Dunkirk Excelsior EXB Series - Manual (Page 19)

19
Riello 40BF blocked vent safety (BVS) Operation
External Action Appliance Response
Thermostat calls for heat.
Call for heat is satisfi ed.
Pressure switch contacts open and
cause burner to re-cycle.
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
120 Vac present. Go to step #2
No voltage
Motor runs.
Motor does not run.
Burner stays in Pre-purge.
Burner continues to purge and
light off with immediate fl ame
dropout.
Burner locks out after trial for
ignition.
Some Aquastats limit post
purge time to 1 minute. Error
unique to early models of
L7248.
OPERATION AND TROUBLESHOOTING