Pressure switch does not close during prepurge 1
The 14 error code on Dunkirk boilers indicates pressure switch does not close during prepurge 1.
Dunkirk 14 means: pressure switch does not close during prepurge 1. The usual causes are the heat exchanger thermal fuse has tripped, fil desserré or bcu ou pb mal programmés. You can safely reset the boiler once — if 14 returns, do not keep resetting. A qualified heating engineer should diagnose the root cause.
What Does 14 Mean
The 14 code is shown by the boiler’s control board when it detects pressure switch does not close during prepurge 1. 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 14 and the boiler stops until the fault is cleared |
Common Causes
Causes documented in the Dunkirk service literature published by dunkirk.com, cross-checked against the manufacturer’s fault-code table.
| Cause |
|---|
| The heat exchanger thermal fuse has tripped |
| fil desserré |
| BCU ou PB mal programmés |
| incorrect grounding of BCU and boiler |
| If the outlet is programmed as a fill valve and there are too many fill attempts |
| If the outlet is programmed as a fill valve and filling takes more than 10 minutes |
Safety Warning
14 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
If the boiler does not start after resetting, contact the installer
Check if there is a leak in the central heating system or if the boiler itself is leaking also check the expansion tank if there is an internal leak
Refer to the Dunkirk service documentation for the detailed procedure. Only a qualified engineer should carry out these repairs.
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Affected Models
Dunkirk models that can display fault code 14:
| Model Family | Output Range | Frequency |
|---|---|---|
| All Dunkirk models | — | Possible |
Frequently Asked Questions
If the boiler does not start after resetting, contact the installer. According to the technical documentation, this is the first check on the list for 14.
14 is not classified as a high-severity fault, so the boiler can be reset once. If 14 comes back, stop resetting: the underlying cause is still there and needs a qualified heating engineer.