No Error Code Displayed; Xiv: Troubleshooting - Burnham ALP105 Installation, Operating And Service Instructions

XiV: Troubleshooting

Turn off power to boiler before replacing fuses or working on wiring.
. Troubleshooting problems where no error code is displayed. Refer to Table 28 for problems and possible causes.
A
Table 28: 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 50)
Boiler fires, but display panel is blank
88
WaRning
POSSIBLE CAUSES
• 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 58 for location). Replace with 5A fuse provided
• Defective AT250 transformer
• Blown "F3" fuse in MCBA (see Figure 58 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 58: MBCa Fuse Location