Boilers: Boiler maintenance tips Maintaining hidden boiler flues
Owners of room-sealed fan assisted boilers are being warned that they may need to make a hidden boiler flue easier to inspect visually or risk having their boilers turned off to avoid a risk of carbon monoxide poisoning.
The danger of hidden boiler flues
The flue is a metal tube that usually comes out of the top of a boiler and goes into the wall. It carries waste gases away from your boiler to be released into the air outside.
A flue in poor condition, combined with a boiler that is not working properly, could put you and your family in danger from carbon monoxide poisoning, which can cause death or serious injury.
If your boiler is situated on an outside wall, it is unlikely you have this type of flue. Alternatively, if your engineer can see all of the flue, you will not need to take any further action.
Gas engineers need to be able to see the flue as part of essential safety checks to ensure that there are no fumes leaking from it due to holes or poorly fitting joints.
If you live in a property that has a boiler flue which cannot be inspected because it is hidden behind a wall, chimney or ceiling, you need to install an inspection hatch, otherwise your boiler may be classified as 'At Risk' and turned off when inspected by an engineer.
Why is carbon monoxide (CO) dangerous?
Around 20 people in Great Britain die each year from CO poisoning caused by faulty gas appliances and flues.
CO is a colourless, odourless, tasteless, poisonous gas produced by incomplete burning of carbon-based fuels, including gas. It is only when the gas does not burn properly that dangerous levels of CO are produced.
CO stops the blood from carrying oxygen round the body and can kill quickly. Symptoms to look out for include headaches, breathlessness, nausea, dizziness, collapse, loss of consciousness, tiredness, drowsiness, vomiting, pains in the chest, stomach pains, erratic behaviour or visual problems. For peace of mind, many people choose to install a carbon monoxide detector to alert them to a carbon monoxide leak.
Do I need flue inspection hatches?
Gas engineers are required to be able to see the flue to inspect it. If your boiler is on an outside wall, it's unlikely you have a hidden flue. If your gas engineer can see all of the flue, you don't need to take any further action.
If you do have a boiler where all or part of the flue cannot be seen, you, or your landlord, will need to arrange for inspection hatches to be fitted so the flue can be inspected.
Industry experts expect that 30,000 properties in the UK may be affected, mostly those that were built between 2000 and 2007 or those properties converted into multiple occupation residences such as flats, around that time.
What if I don't install a hatch?
From 1 January 2013 gas engineers who are unable to visually inspect the length of your boiler flue should advise you that it is 'At Risk' and will ask your permission to turn it off, to ensure they comply with industry guidance. This may occur if you call in an engineer to service or repair your boiler.
You can refuse to let the gas engineer permission to turn off your boiler, but you will be asked to sign paperwork to confirm you accept responsibility for those defects identified in the system which could result in a serious incident.
How much will inspection hatches cost me?
It varies from property to property. Hatches should be at least 300mm x 300mm and positioned within 1.5m of any joint in the flue system. The number of hatches you need will depend on how long your flue is.
Basic inspection hatches must comply with the Building Regulations and are likely to cost from £75, though you may choose to fit more expensive ones for cosmetic reasons.
Costs for fitting the inspection hatches will be extra.
Who do I approach to install inspection hatches?
A competent builder or building services company should be able to fit the inspection hatches. Which? members can find a recommended local builder using our recommendation website Which? local.
The builder will need to speak to a registered gas engineer to find out how many inspection hatches are needed and where they should be placed.
Where can I get more information?
You can find more information about the problems that led to this advice and how to deal with the issue at the Gas Safe Register website.