Flue Liner Warranties: What You Actually Need to Register and Keep on File

A customer rings you four years after you fitted their stove. Their flexible liner has failed, there's a hint of rust showing through where the cowl meets the chimney pot, and they're waving a brochure that promised a 20 year guarantee. You didn't manufacture the liner. But you're the one they're calling, because you're the name they remember.

Whether that call goes well or badly usually comes down to what got written down on the day you did the job, not what the sales brochure said the warranty covered.

The warranty length on the box rarely means what customers think it means

Flexible liner manufacturers advertise generous terms. Schiedel's guarantee runs for the appliance's own guarantee period or 20 years, whichever is longer. Some suppliers market "lifetime" cover on the liner itself. On paper, that sounds like a customer is protected for as long as they own the house.

In practice, warranty length is only one half of the agreement. The other half is a list of conditions and exclusions, and that's where most claims actually get decided. Flue-Pipes.com's own terms, for example, exclude rubber joints, paints and coatings, loose insulation, installation labour, and any damage linked to non-compliant installation or extreme weather. A "lifetime warranty" that excludes labour still leaves the customer paying to have the failed liner physically removed and a new one fitted, even if the material itself gets replaced free.

Homeowners on forums like MoneySavingExpert have compared notes on this for years. A recurring complaint is liners failing within six or seven years despite a 20 year headline figure, with claims then denied over things like "slumbering" the fire overnight, burning unseasoned wood, or condensation the manufacturer attributes to misuse. None of those conditions tend to be printed clearly on the box. They surface when a claim gets made.

Registration isn't paperwork, it's the thing that makes the guarantee exist at all

This is the part that trips up installers more than the exclusions do. Most flexible liner guarantees aren't automatic. They have to be registered, and there's usually a window to do it in.

Schiedel requires registration within 30 days of installation, either through their online portal or their installer app, along with evidence that the work was carried out by a HETAS registered installer or signed off by a building control inspector. Miss that window and the manufacturer's own terms say the guarantee claim is invalid, regardless of whether the liner itself was faulty.

Other suppliers ask for more detail at registration than installers expect: sales order number, installer name and HETAS number, company address, installation date, customer name and address, liner type, length and diameter, and the appliance and fuel type it's connected to. If you're capturing that information from memory a few weeks after the job, on a day when you're trying to get to the next installation, something usually gets missed or logged wrong.

What to capture on the day, every time

A few things are worth treating as non-negotiable at the point of installation, not as optional admin to catch up on later:

• The liner's make, length, and diameter, taken from the product itself rather than the original order, in case what got fitted differs from what was quoted.

• The registration confirmation, saved as a screenshot or PDF, not just ticked off as "done." If a claim is challenged later, you want proof the registration actually went through inside the window, not just that you meant to do it.

• The fuel type specified to the customer, in writing. If a claim gets denied over unseasoned wood or the wrong fuel years later, the useful evidence is what you told them to burn, not what they actually burned.

• Photos of the completed flue run and connections, the same completion photos you're likely already taking for HETAS purposes. These do double duty as evidence the liner was fitted correctly and to spec.

None of this guarantees a claim gets approved. Manufacturers still control the process and the exclusions still apply. What it does is put you in a position to say, with evidence rather than memory, exactly what was fitted, when, and to what standard. That's a very different conversation with an unhappy customer than trying to reconstruct a job from four years ago off the top of your head.

Why this usually lands on the installer, not the manufacturer

When a liner fails, the customer's instinct is rarely to phone the liner manufacturer directly. It's to phone the person who fitted it. That's true even when the fault sits entirely with the product, and it's true even years after the job's finished, because you're the relationship they trust and the name on the invoice.

That means the registration and the records aren't really there to protect the manufacturer's warranty process. They're there to protect you when a customer calls with a complaint and you need to show, quickly and confidently, that the job was done properly and the guarantee was registered on time. An installer who can pull that up in thirty seconds looks like a professional. One who has to say "let me have a dig through some old emails" looks like the problem, even when they aren't.

Keeping it where you'll actually find it

The liner details, registration proof, fuel spec, and completion photos for a job are exactly the kind of thing that's easy to file properly on installation day and painful to reconstruct months or years later. In BurnerCRM, that information sits against the job record itself, alongside the HETAS reference and everything else from that installation, so when a customer calls about a liner that's failed in year six, you're not searching through old inboxes to work out what was actually fitted and whether the guarantee was ever registered in the first place.