Occurs if display communications out for 30 seconds
The DISPLAY COMM Fault error code on Weil-Mclain boilers indicates occurs if display communications out for 30 seconds.
Weil-Mclain DISPLAY COMM Fault means: occurs if display communications out for 30 seconds. On this component the documented failure modes are occurs if display communications out for 30 seconds, communication lost between board and control panel or control board (pcb) faulty. You can safely reset the boiler once — if DISPLAY COMM Fault returns, do not keep resetting. A qualified heating engineer should diagnose the root cause.
What Does DISPLAY COMM Fault Mean
The DISPLAY COMM Fault code is shown by the boiler’s control board when it detects occurs if display communications out for 30 seconds. The boiler then stops instead of continuing to run in that condition: the code is the appliance reporting a problem, not proof that the boiler is broken.
| What you see on the boiler |
|---|
| The display shows DISPLAY COMM Fault and the boiler stops until the fault is cleared |
Common Causes
The first cause below is the one the Weil-Mclain service literature publishes for this code (source: weil-mclain.com). The others are the failure modes documented for the same component on other boilers, confirmed by 6 different manufacturers.
| Cause |
|---|
| Occurs if display communications out for 30 seconds |
| Communication lost between board and control panel |
| Control board (PCB) faulty |
Safety Warning
DISPLAY COMM Fault involves electrical or pressure-related components. Do not attempt repairs without proper qualifications. Ensure the boiler is electrically isolated before any inspection. If you notice water leaks, unusual sounds, or pressure anomalies, contact a qualified heating engineer immediately.
Parts & Prices
Prices shown are indicative. Actual prices and availability vary by region.
How to Fix It
Automatically resets when communication is re-established
Check the cable between the boiler board and the control panel or room control, including the connectors at both ends, and confirm the two devices are paired as the manual describes.
Only after every other check: verify the board’s supply and connections, and replace the board — fitting the correct boiler chip card or coding key where the model requires one.
Refer to the Weil-Mclain service documentation for the detailed procedure. Only a qualified engineer should carry out these repairs.
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Affected Models
Weil-Mclain models that can display fault code DISPLAY COMM Fault:
| Model Family | Output Range | Frequency |
|---|---|---|
| All Weil-Mclain models | — | Possible |
Frequently Asked Questions
Automatically resets when communication is re-established. According to the technical documentation, this is the first check on the list for DISPLAY COMM Fault.
DISPLAY COMM Fault is not classified as a high-severity fault, so the boiler can be reset once. If DISPLAY COMM Fault comes back, stop resetting: the underlying cause is still there and needs a qualified heating engineer.