What is an uncommissioned stove?

An uncommissioned stove, also referred to as a decommissioned wood burner, relates to a wood-burning stove that has been disabled by a HETAS Registered Installer pending maintenance or further inspection. This maintenance could involve a range of components within the installation, ranging from the stove to the flue system.

Whilst your appliance is uncommissioned it must not be used under any circumstances – it could pose a health or fire risk and must be recommissioned by a competent person before it can be used again.

Uncommissioned appliances

Whilst your wood burner is uncommissioned, it will have a warning label in clear view. This label indicates that the appliance must not be used until your HETAS Registered Installer has recommissioned it, ensuring its safe use. This label serves as a clear warning and would be left by the installer following an inspection that has found a fault in your installation.


As some remedial works take a significant amount of time, such as major repairs or replacements to your flue system, your installer may not always be able to provide an immediate fix to the issue your installation has encountered. By uncommissioning your appliance and clearly marking it with an uncommissioned label, your installer is providing clear instructions that the appliance/installation is pending maintenance and must not be used until this is completed.

Recommissioning process

When recommissioning an appliance, your HETAS Registered Installer will undertake a range of tests to ensure that your installation is safe to be recommissioned:

  1. Chimney integrity test (smoke test 1)
  2. Chimney draw test (smoke test 2)
  3. Flue draught test
  4. Flue draught interference test (depressurisation test)
  5. Spillage on refuel test

These tests provide assurance that your installation is working correctly and safely.

Following a recommission

Once your HETAS Registered Installer has completed recommissioning your appliance and is satisfied that your installation is working safely, they will supply your with a commissioning sheet. This commissioning sheet is evidence that your installation has been recommissioned by a competent installer. It is important that you keep your commissioning sheet safe is it could be required should your installation require further maintenance in the future.

Why has my stove been uncommissioned?

Your installer will communicate and document the reason(s) that your appliance or installation have been uncommissioned. There are a range of events that warrant uncommissioning, including:

  • Flue system replacement or changes
  • Appliance replacement or significant location change
  • Recess damage repair
  • Hearth replacement or alterations

As every installation is unique and problems can arise in a variety of ways, this list is not exhaustive and your installer could find alternate reasons to warrant uncommissioning your appliance.

Chimney sweeping

Your installer will recommend that you get your chimney swept before your appliance is recommissioned. This provides further assurance that your installation is safe and can function efficiently. Your installer may be able to provide this service for your or, if not, you can find a local HETAS Approved Chimney Sweep using our search.

The HETAS Advice Hub has a range of tips and advice to ensure you can continue to burn safely and responsibly.


HETAS, Severn House, Unit 5 Newtown Trading Estate, Green Lane, Tewkesbury, GL20 8HD