Install Instructions
31
Troubleshooting Tree for Section VII, Step E
WATERLINE ABOVE LOWEST PERMISSIBLE LEVEL?
YES
REPLACE BLOWER AFTER 
CHECKING FOR BROKEN 
WIRES AND LOOSE 
CONNECTIONS.
CHECK DPST RELAY:
24 VOLTS AT COIL?
120 VOLTS AT TERMINALS 
'1' AND '3'?
24 VOLTS AT SUCTION 
PRESSURE SWITCH 
TERMINAL 'C'?
REPLACE RELAY AFTER CHECKING FOR 
BROKEN WIRES AND LOOSE CONNECTIONS.
REPLACE SUCTION 
PRESSURE SWITCH.
NO
NO
YES
YES
CHECK FOR BROKEN 
WIRES AND LOOSE 
CONNECTIONS.
YES
24 VOLTS ACROSS BOTH 
LIMIT TERMINALS?
NO
REPLACE LIMIT AFTER CHECKING FOR BROKEN 
WIRES AND LOOSE CONNECTIONS.
YES
REPLACE RELAY AFTER CHECKING FOR BROKEN 
WIRES AND LOOSE CONNECTIONS.
24 VOLTS AT SPST RELAY 
TERMINALS '1' AND '3'?
24 VOLTS AT SUCTION 
PRESSURE SWITCH 
TERMINAL 'NC'?
NO
24 VOLTS AT BOTH L.W.C.O. 
TERMINALS 'B-B'?
YES
NO
REFER TO L.W.C.O. MANUFACTURER'S 
TROUBLESHOOTING INSTRUCTIONS
NO
FILL BOILER TO NORMAL WATERLINE
NO
GAUGE PRESSURE LESS THAN LIMIT CUT-IN SETTING?
ALLOW SYSTEM PRESSURE TO FALL BELOW LIMIT CUT-IN 
PRESSURE, OR INCREASE LIMIT CUT-IN SETTING.
CONTINUITY ACROSS FLAME 
ROLLOUT SWITCH (FRS)?
YES
NO
NO
YES
YES
NO
YES
REPLACE THERMOSTAT 
AFTER CHECKING FOR 
BROKEN WIRES AND 
LOOSE CONNECTIONS.
YES
24 VOLTS AT SPST RELAY 
COIL?
NO
24 VOLTS ACROSS 
TRANSFORMER BLUE AND 
YELLOW WIRES?
REPLACE TRANSFORMER 
AFTER CHECKING FOR 
BROKEN WIRES AND 
LOOSE CONNECTIONS.
NO
PROVIDE POWER TO 
BOILER
120 VOLTS ACROSS 
TRANSFORMER BLACK 
AND WHITE WIRES?
YES
CAUTION
REPLACE FLAME ROLLOUT SWITCH. DETERMINE CAUSE OF EXCESSIVE 
TEMPERATURE (BLOCKED FLUE, EXCESSIVE RATE CAUSED BY HIGH 
MANIFOLD PRESSURE OR OVERSIZED ORIFICES, SUCTION PRESSURE 
SWITCH FAILURE, ETC.) BEFORE PLACING BOILER IN OPERATION.










