Burnham ALP150 - Manual (Page 88)

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XiV: Troubleshooting
Figure 58: MBCa Fuse Location
CONDITION
POSSIBLE CAUSES
Display Blank, Fan off, LWCO lights off
• No 120VAC Power at boiler. Check breaker and wiring between breaker panel and boiler
Display Panel Blank, Fan running
• 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
Display reads “U.125” continuously, Fan running
• Defective AT250 transformer
• Blown “F3” fuse in MCBA (see Figure 58 for location). Replace with 4A slow-blow fuse
provided
Boiler not responding to call for heat,
Status code on display =”0” (see Figure 50)
• Boiler is not seeing call for heat. Check thermostat or zone wiring for loose connection,
miswiring, or defective thermostat/zone control.
Boiler fires, but display panel is blank
• Loose ribbon cable
• Defective display
Table 28: no Error Code Displayed
A .
Troubleshooting problems where no error code is displayed. Refer to Table 28 for problems and possible causes.
WaRning
Turn off power to boiler before replacing fuses or working on wiring.