Weil mclain ultra boiler HARD LOCKOUT CODE 12
Asked Jan 10, 2010, 07:38 PM
My Weil Mclain Ultra 80 Boiler display shows a hard lockout code E12... Pressing the reset button does nothing... ie the display will not then change back to the normal standby or operating mode... Removing the thermostat wires and then jumpering the thermostat terminals 5 and 6 on the low voltage terminal strip does not bring on the boiler as per usual. The external limits are closed, as there are jumper wires between terminals 6 and 7 and between 6 and 8.. Both glass fuses inside the Honeywell MCBA control module are fine.. and the control module is only 30 months old , with no visible damage on inspection. Why won't the boiler start ?