E09 error code
ACV Prestige MkIII E09 error code – Gas-valve relay error
What does ACV Prestige Solo and Excellence MkIII condensing boiler E09 mean?
ACV documents E09 for the Prestige Solo and Excellence MkIII range as: Gas-valve relay error.
The code identifies the condition detected by the product; it does not always identify the failed component on its own. Confirm the full code and exact model before ordering parts or attempting a reset.
The ACV Prestige Solo and Excellence MkIII condensing boiler E09 error code indicates aCV documents E09 for the Prestige Solo and Excellence MkIII range as: Gas-valve relay error. This guide explains what the code means, the symptoms and likely causes, the checks that are safe to make, and when to stop and arrange an authorised repair.
Symptoms you may notice
The Prestige controller displays E09. The boiler may lock out, stop firing or restrict normal heating and hot-water operation.
Common causes
The official ESYS fault table associates E09 with gas-valve relay error. The exact wiring, sensor, combustion, pressure or controller condition must be confirmed on the appliance.
Before you start troubleshooting
Use the display, rating label or product menu to confirm the exact model. Similar-looking codes can have different meanings across product generations and regions.
- Record the complete code before switching the equipment off.
- Check only user-accessible controls, filters and external connections described in the manual.
- Do not open gas, refrigerant, combustion or electrical compartments.
Troubleshooting steps
Record E09 and the exact Prestige model. Check only visible pressure, power, controls and external conditions allowed by the user instructions. Internal measurements and component checks require an approved engineer.
Can you fix this error code yourself?
The safest next step depends on the exact model and the cause behind the code. External checks may help, but a returning fault needs professional diagnosis.
A successful reset is not proof that the underlying issue is fixed. If E09 reappears, note when it happens and give that information to the service engineer.
Reset instructions
Use the ESYS reset only as described in the official ACV instructions. If E09 returns, stop resetting and contact an approved installer.
Applicable products and models
Prestige Solo and Excellence MkIII condensing boilerPrestige Solo 18 MkIII; Prestige Solo 32 MkIII; Prestige Excellence 18 MkIII; Prestige Excellence 32 MkIIIManual 664Y4200 revision H, March 2011When to contact a professional
Contact ACV support or an approved heating engineer when E09 persists, returns after a permitted reset, or requires internal testing or component replacement.
Frequently asked questions
What does ACV Prestige Solo and Excellence MkIII condensing boiler E09 mean?
ACV documents E09 for the Prestige Solo and Excellence MkIII range as: Gas-valve relay error.
Can I fix ACV Prestige Solo and Excellence MkIII condensing boiler E09 myself?
Some external checks may be suitable for the user, but the result depends on the exact model and cause. Use the official manual and arrange service if the code returns.
Should I reset the product after code E09?
Use the ESYS reset only as described in the official ACV instructions. If E09 returns, stop resetting and contact an approved installer.
When should I arrange a repair?
Contact ACV support or an approved heating engineer when E09 persists, returns after a permitted reset, or requires internal testing or component replacement.