Weil McLain F13

What does Weil McLain F13 mean?

F13 indicates the exhaust gas temperature (flue probe) sensor has gone outside its valid operating range due to a short circuit or open circuit. All heat demands are disabled while the fault is active. The fault resolves automatically once the sensor reading returns to the valid range.

Symptoms

• Boiler displays F13 and shuts down all heating operation.
• No central heating or domestic hot water while fault is active.
• Boiler may have been running in F07 high-exhaust-temperature mode prior to F13 appearing.
• Fault clears and recurs if wiring to the exhaust probe is intermittently faulted.

Common causes

• Exhaust gas temperature probe damaged or failed (open or short circuit).
• Probe wiring shorted from contact with hot vent surfaces.
• Probe wiring disconnected at the probe body or control board.
• Corroded probe connector causing resistance out of the valid sensor range.

Diagnostic steps

1. 01

   Locate the exhaust temperature probe

   Find the exhaust probe on the flue outlet section of the boiler. The AquaBalance Series 2 boiler manual shows its exact position in the venting assembly.

2. 02

   Inspect the probe and wiring

   Check the probe body and wiring for signs of heat damage, melting, or physical contact with the vent pipe wall. Repair or reroute wiring that contacts hot surfaces.

3. 03

   Re-seat the probe connector

   Disconnect and firmly re-seat the exhaust probe connector at the control board. Inspect for oxidation or bent pins. Reset the boiler and monitor.

4. 04

   Measure probe resistance

   Disconnect the probe and measure its resistance at a known temperature. An open circuit or a dead short confirms the probe must be replaced.

5. 05

   Replace the exhaust probe

   Install a genuine Weil-McLain replacement exhaust temperature probe. Restore power, reset, and run the boiler through a full cycle to confirm F13 is resolved.

When to call a professional

Call a licensed technician if probe replacement does not resolve F13 or if the fault follows repeated F07 events. Persistent post-replacement F13 indicates a control board input circuit fault. Recurring F07 leading to F13 requires comprehensive vent system inspection and possibly combustion recalibration by a qualified technician.