Weil-McLain GV90+ - CHART 8 Troubleshooting Sensor Ground and POWER light Solid and;or “LCO” shown on display

Part number 550-142-903/1016
90
Is harness securely connected to control?
Ye s N o
s Control had poor connection,
boiler should resume operation.
s Secure connector.
Is the Sensor ground light still solid or flashing?
No Yes
s Check ground continuity from Pin 4 of P5
terminal to ground connection.
Is there continuity?
No Yes
s Secure wire to earth ground.
s
Retest.
Is the Sensor ground light still solid or
flashing?
No Yes
s Ground was improperly connected.
s Boiler should resume operation.
s Check for stray voltage on ground and
neutral wires.
Ye s N o
s Check and secure ground source to
earth ground connection.
Is the Sensor ground light still solid or
flashing?
Ye s N o
s Correct incoming power and ground-
ing issues.
s Replace control.
GV90+ Series 2 GAS-FIRED WATER BOILER — Boiler Manual
CHART 8
Troubleshooting Sensor Ground and POWER light Solid
and/or “LCO” shown on display
%LECTRICALSHOCKHAZARD — Wherever you see TURN OFF POWER, follow the instructions. Failure to follow
instructions could result in severe personal injury, death or substantial property damage.
Troubleshooting (continued)