Buderus Intermittent Safety Lockout

Furnace frequently locks out and must be manually reset, but no specific code is shown

Advertisements

Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Advertisements

Possible Causes

Loose electrical connections, Marginal flame signal, Intermittent fan or pump failure, Control board fault

How to Fix / Troubleshooting

Safety: Do not repeatedly reset a locking-out furnace without finding the cause.

Steps:

  • Record behavior: Note when lockouts occur (startup, mid-run, DHW calls) to help pinpoint the issue.
  • Inspect connections: With power off, gently tug on all plug-in connectors at the Buderus control board, gas valve, fan, and sensors. Reseat any loose plugs.
  • Clean flame sensor: A weak flame signal is a common cause of intermittent lockouts; clean the sensor as described earlier.

Persistent unexplained lockouts require professional diagnostic tools to monitor signals and combustion.

Advertisements

Repair Difficulty

Hard 4/5

Required Part

Buderus Control Board (Main PCB)
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements