Does skipping a boiler service void the warranty?

The short answer

For the manufacturers checked here, yes: an annual service by a licensed technician is a stated condition of the extended warranty, and a missed or undocumented service can cost you the cover. How harsh the consequence is depends on the maker. Baxi UK says the warranty falls back to one year. Immergas Greece says it may reject claims linked to the missed service. Vaillant UK says only that the owner must arrange an annual service to keep the guarantee valid.

This guide covers three makers and is not a statement about every boiler. Your own warranty document is the one that binds you.

What each maker writes

Immergas (Greece). The Greek 7-year warranty document says that keeping the warranty depends on a yearly preventive service by a licensed technician, paid for by the owner. It tells the owner to keep the combustion sheets (Φύλλα Καύσης). If the service was not done or cannot be documented, the company reserves the right to reject warranty claims related to that omission. The same document also lists installation conditions, such as a magnetic sludge separator and a "Y"-type water filter, so the service is not the only requirement.

Baxi (Greece). The baxi.gr warranty FAQ says the basic condition for the warranty is that installation and the yearly service and check are done by a licensed technician, who issues the matching flue-gas sheet. It also says that fitting a magnetic particle separator extends the warranty of its condensing gas boilers by 2 years.

Baxi (UK). The UK FAQ ties the warranty to registration within 30 days of installation, a completed installer checklist and an annual service. If these conditions are missed, the warranty "will revert to the standard one year". That is a UK page, so it is a useful comparison rather than the Greek terms.

Vaillant (UK). The installer-facing guarantee page says that to keep the guarantee valid, the homeowner must arrange an annual service, and that the appliance must be registered within 30 days of installation. It does not spell out what happens if a service is missed. Check the guarantee document for your model and country.

What it does not change

A manufacturer's guarantee is a commercial guarantee. According to the EU's Your Europe portal, it adds to the 2-year legal guarantee and does not replace it. So a service condition attaches to the extra cover the maker chose to offer. It does not remove your legal rights as a consumer. If you have a dispute, read your national consumer rules or ask a consumer organisation rather than relying on a summary like this one.

What to keep as proof

• The signed service sheet for every year, not just the latest
• The combustion readings, if they are on a separate sheet
• The technician's name and licence details as printed on the sheet
• The warranty document and the date the boiler was first fired up

Track it in Epimeleia

Add the boiler to the property in Epimeleia, set a 12-month service interval and attach each year's service sheet to the record. The reminder arrives before the date slips, and the proof for any future warranty claim is already on file.

Before you rely on this

Warranty terms change by model, country and purchase date. The wording above was read from each maker's own page or document on 2026-10-21. Confirm the terms in the paperwork that came with your boiler.