LOP error code
ACV Prestige MkIII LOP error code – Low heating-system pressure
What does ACV Prestige Solo and Excellence MkIII condensing boiler LOP mean?
ACV documents LOP for the Prestige Solo and Excellence MkIII range as: Low heating-system pressure.
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 LOP error code indicates aCV documents LOP for the Prestige Solo and Excellence MkIII range as: Low heating-system pressure. 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 LOP. The boiler may lock out, stop firing or restrict normal heating and hot-water operation.
Common causes
The official ESYS fault table associates LOP with low heating-system pressure. 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
Check the displayed heating-system pressure. Refill only as described in the ACV user instructions. If pressure drops repeatedly, stop and arrange a leak and pressure-sensor assessment.
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 LOP 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 LOP 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 LOP 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 LOP mean?
ACV documents LOP for the Prestige Solo and Excellence MkIII range as: Low heating-system pressure.
Can I fix ACV Prestige Solo and Excellence MkIII condensing boiler LOP 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 LOP?
Use the ESYS reset only as described in the official ACV instructions. If LOP returns, stop resetting and contact an approved installer.
When should I arrange a repair?
Contact ACV support or an approved heating engineer when LOP persists, returns after a permitted reset, or requires internal testing or component replacement.