E.14: Diverter valve Euro B/S 170/0 PARTS REPLACEMENT
The E14 error code on Vaillant boilers indicates e.14: diverter valve euro b/s 170/0 parts replacement.
Vaillant E14 means: e.14: diverter valve euro b/s 170/0 parts replacement. The usual causes are diverter valve stuck or not switching to dhw mode, dhw thermistor (ntc) fault or plate heat exchanger blocked with limescale. You can safely reset the boiler once — if E14 returns, do not keep resetting. A qualified heating engineer should diagnose the root cause.
What Does E14 Mean
The E14 code is shown by the boiler’s control board when it detects e.14: diverter valve euro b/s 170/0 parts replacement. 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 E14 and the boiler stops until the fault is cleared |
Common Causes
Causes documented in 2 technical sources.
| Cause |
|---|
| Diverter valve stuck or not switching to DHW mode |
| DHW thermistor (NTC) fault |
| plate heat exchanger blocked with limescale |
| flow sensor or turbine not detecting water flow |
| DHW temperature set too low |
| microswitch or flow switch fault |
Safety Warning
E14 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.
Step-by-Step Diagnosis
1. Open a hot water tap and check if the boiler fires — if not, check the flow sensor/turbine. 2. Check the diverter valve — with a hot water tap open, feel the central heating flow pipe
if it is hot, the diverter is not switching. 3. Check the DHW NTC sensor — measure resistance and compare with manufacturer's chart. 4. Check the plate heat exchanger — if the boiler fires but water is lukewarm, the PHE may be scaled. 5. Verify the DHW temperature setting on the boiler controls
How to Fix It
Replace or free the diverter valve if stuck
replace the DHW thermistor if faulty
flush or replace the plate heat exchanger if scaled
clean or replace the flow sensor/turbine
adjust DHW temperature setting
Refer to the Vaillant service documentation for the detailed procedure. Only a qualified engineer should carry out these repairs.
Diagnostic Tools
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Affected Models
Vaillant models that can display fault code E14:
| Model Family | Output Range | Frequency |
|---|---|---|
| All Vaillant models | — | Possible |
Frequently Asked Questions
Replace or free the diverter valve if stuck. According to the technical documentation, this is the first check on the list for E14.
E14 is not classified as a high-severity fault, so the boiler can be reset once. If E14 comes back, stop resetting: the underlying cause is still there and needs a qualified heating engineer.