Weil-McLain Boiler A113 Error — What It Means
A113 is not a documented universal fault code across all Weil-McLain boilers. The manufacturer publishes model-specific error codes tied to each control platform, and the exact meaning of A113 depends on your boiler model and control board type. Weil-McLain directs technicians to consult the specific service manual for the installed model to decode stored faults and follow the correct troubleshooting sequence.
Without the model number and control type, any guess at what A113 means would be unreliable. If your display or fault history shows A113, locate the model and serial tag on the boiler jacket, then reference that model’s installation and service guide or contact a qualified heating contractor who can access the fault history menu and interpret the code correctly.
Before You Replace Anything
Do not replace the control board or main valve without verifying the exact fault definition and checking upstream sensors, wiring, and gas supply first. Many apparent control faults are actually sensor or connection issues.
Common Causes
- Model-specific sensor fault (~30%) Many Weil-McLain controls log faults when a temperature, pressure, or flame sensor reads out-of-range or loses connection.
- Communication error between control boards (~25%) Some models use multiple circuit boards, and an A-series code may indicate a lost signal or wiring issue between them.
- Ignition or flame-proving fault (~20%) If A113 maps to an ignition sequence error on your model, it may result from a dirty flame sensor, weak igniter, or low gas pressure.
- Supply-voltage or grounding problem (~15%) Unstable line voltage or a missing equipment ground can cause intermittent control faults that log as numeric or alphanumeric codes.
- Control-board firmware or memory fault (~10%) Older or failing boards occasionally log non-standard codes when internal memory or the processor experiences a transient error.
Quick Diagnosis
Answer these to narrow it down fast.
Does your boiler manual or the control-panel label list an A113 code with a definition?
No: The code may be model-specific or a non-standard log entry. Contact Weil-McLain support or a local heating contractor with the full model number.
Does the fault clear after a power cycle and the boiler runs normally for at least one heating cycle?
No: The fault is persistent. Proceed with model-specific diagnostics or call a technician to read the full fault history and test components.
Can you access the boiler's diagnostic or fault-history menu using the control-panel buttons?
No: Some Weil-McLain controls require a service tool or key sequence to enter diagnostics. A qualified technician has the tools and training to retrieve the log.
Step-by-Step Fix
- Identify your boiler model and control type. Look for the nameplate on the front or side of the jacket and write down the full model number and serial number.
- Locate the service manual. Check inside the boiler jacket door for a plastic pouch holding the installation and operating instructions, or download the manual from the Weil-McLain website using your model number.
- Search the manual’s fault-code table for A113 or any alphanumeric code starting with A. Note the description and the recommended checks.
- Power-cycle the boiler. Turn off the service switch (or the circuit breaker feeding the boiler) for 30 seconds, then restore power and observe whether the code returns immediately or after the next call for heat.
- Inspect sensor and harness connections. With power off, check that all wire connectors at the control board, temperature sensors, pressure switches, and flame sensor are fully seated and free of corrosion.
- Call a licensed heating technician if the code returns, if you cannot find it in your manual, or if the manual directs you to check gas pressure, flame signal, or board voltages. These tests require calibrated meters and safe-handling procedures.
- Document the repair. If a part is replaced under warranty, Weil-McLain requires the failed part number and a description of the fault for warranty processing through your contractor.
Parts Often Needed
| Part | Notes |
|---|---|
| Model-specific control board or module | Amazon | Only order after confirming the part number from your boiler’s service manual and verifying the fault with a technician. |
| Temperature or pressure sensor | Amazon | If diagnostics point to a sensor fault, match the sensor type and connector to your exact model. |
When to Call a Pro
Call a licensed heating contractor immediately if the boiler will not ignite, if you smell gas, or if the system pressure exceeds 25 PSI. Even if the boiler runs, a professional should diagnose any persistent fault code because Weil-McLain boilers integrate gas controls, high-voltage ignition, and pressure-relief systems that require trained service. The technician can retrieve the full fault history from the control board, measure flame signal and gas pressure, and test sensor resistance and voltages against the factory specifications in the service manual. Attempting these checks without the correct tools and training risks personal injury, equipment damage, and voiding your warranty.
Rough cost: A pro service call runs about $150-400 depending on the actual fault and required parts.