Troubleshooting; Xiv. Troubleshooting - Burnham FREEDOM FCM120 Installation, Operating And Service Instructions

Turn off power to boiler before replacing fuses or working on wiring.
A. Troubleshooting problems where no error code is displayed:
TABLE 14.1: NO ERROR CODE DISPLAYED
CONDITION
Display Blank, Fan off, LWCO lights off
Display Panel Blank, Fan running
Display reads "U.125" continuously, Fan running
Boiler not responding to call for heat, Status code on
display ="0" (see Figure 11.1)
Boiler fi res, but display panel is blank
60

XIV. Troubleshooting

WARNING
• No 120VAC Power at boiler. Check breaker and wiring between breaker panel
and boiler
• Loose 120VAC connection wiring between boiler J-Box and MCBA
• Blown "F1" fuse in MCBA (see Figure 13.2 for location). Replace with 5A fuse
provided
• Defective AT250 transformer
• Blown "F3" fuse in MCBA (see Figure 13.2 for location). Replace with 4A slow-
blow fuse provided
• Boiler is not seeing call for heat. Check thermostat or zone wiring for loose
connection, miswiring, or defective thermostat/zone control.
• Loose ribbon cable
• Defective display
Figure 14.2: MBCA Fuse Location
POSSIBLE CAUSES