CHIMNEY TERMS EXPLAINED

• Flue: Is the void through which the products of combustion are removed into the atmosphere

• Flue liner: Is the material used to form the flue within the chimney

• Flue pipe: This is the metal pipe used to connect an appliance to the flue

• Chimney: Is the structure surrounding one or more flues

• Chimney terminal: This is another word for pot, cowl, or another method of finishing off the top of the chimney

• Flaunching: This is the cement or mortar slope around the chimney top. It has two purposes, to hold the chimney pot in place and to direct water away from the chimney stack.

 

WHY A SPRING CLEAN RECOMMENDED

It is recommended that you have your chimney swept after the winter burning season rather than leaving it to the Autumn. There are a couple of reasons for this;

 

• Saves you money in the long term.

• Soot contains acid. If left, that acid will eat away at the inside of your chimney or flue. So it makes sense to get your flue cleaned after the burning season. Which will increase the life span of the flue and save you money in the long run. Repairs to damaged chimneys and liners can be extremely costly. If they are not well maintained and fall into disrepair, if used, there is a real risk that carbon monoxide will enter the rooms of the house through the walls. Particularly in the upstairs bedrooms.

• From September and through the winter months, chimney sweeps are extremely busy and it can be difficult to find one who does not have a waiting list. Another reason why it is recommended to arrange for your chimneys to be swept during the non-burning months. Particularly if you have had problems with your chimney and have put off getting the chimney sweep in because the winter is nearly over. If major problems are identified, or you decide to replace your open fire with a stove, which is far more efficient than an open fire, this will give your sweep plenty of time to arrange for repairs and replacements whilst the appliance is not in use. You can guarantee that these things always go wrong just when you need them if they are not properly maintained.

 

RUST

If there is rust, there is moisture. Either from within the room or from the chimney. If there is water coming down the chimney, consider a cowl. I would recommend a euro cowl, which will not only keep the water out but also the birds.

If you have an open fire, there may be damage to your chimney or the flaunching of the chimney. This would need to be investigated by a professional. As it involves a chimney, I would recommend that you employ the services of a qualified chimney sweep who is best qualified in all things to do with your chimney, rather than a builder.

Around the door closure area of your stove. In which case I would suggest leaving the door slightly ajar when not in use.

 

WHICH FUEL?

Smokeless fuel or Wood?

 

SMOKELESS FUEL

Do not produce much soot. However, what it does produce is very acidic. If you burn these types of fuel it is advisable to get your flue/stove swept soon after the burning season, so that the soot does not sit inside your flue or in your stove for a long period of time and cause problems with corrosion.

 

WOOD

Wood is much cleaner and easier to handle than coal. However, it is important not to burn green or wet wood as this creates creosote which is highly flammable.

Wood does produce soot and must be burned with the right amount of air input to minimise the production of soot. If the glass of your stove blackens every time you burn, then the airflow is incorrect and needs to be adjusted. This is called air wash. There should be a lever or similar that will allow you to adjust the airflow.

 

MIXING WOOD & COAL

If you like to use wood in the first instance then top up with coal to keep the fire in overnight for example, then your flue will need more frequent sweeping.

Wood and coal burn very differently. Coal is slow burning and likes airflow from underneath and so needs to be burned on a grate so that the ash can fall away and the fire can burn as fast as possible.

Wood, however, is fast burning and likes airflow from the top. If is burned on a grate, the wood will burn very fast and the fire be difficult to control. This is why wood is best burned on a bed where it will burn more slowly.

Burning them together also minimises the individual benefits of these two very different types of fuel.

 

SMOKELESS FUELS

Plans to phase out the sale of house coal and wet wood are coming to fruition.

Manufactured smokeless fuels are often anthracite based making them more environmentally friendly than house coal.

The composition of smokeless fuels means that it is much more efficient than house coal. It has a longer burning rate and a better heat output than coal which also makes it cheaper to use than coal. The high carbon content in smokeless fuels also means less ash, which means less emptying the grate, which is always good news, especially on cold, rainy days!

 

ANTHRACITE

There are 4 layers of coal formation, peat, lignite, bituminous, and anthracite.

Anthracite is the highest rank of coal and is often referred to as hard coal. It contains a high percentage of carbon (86% to 97%) and a low percentage of volatile matter which makes it harder to light than coal.

When burning anthracite in a multi-fuel stove, always start with a clean grate, as ash can block the airflow, making it harder to light.

Anthracite is one of the cleanest types of coal to burn as it produces less smoke than bituminous coal.

 

BITUMINOUS COAL

Is easier to light than anthracite but not as clean burning as anthracite as it produces thick black smoke and has a high sulphur content.

 

WHY DOES THE GLASS ON MY LOG BURNER GO BLACK?

​If the glass on your wood burning stove is often black this could be for one of the following reasons;

​Too much moisture – ensure that your wood is dry. Green or freshly felled logs are not good to burn in a domestic stove or open fire until they have been dried to 20% moisture content or less. The most reliable way to measure this is by using a wood moisture meter.

​​​Fire not burning hot enough – wood burns in stages. When the fire is not burning hot enough (is smoky), it does not burn hot enough to allow the secondary burn to engage and so it is not burning hot enough to burn off the creosote on the glass.

​​​Not enough airflow – control the airflow using the controls on your stove. If you are unsure, check your stove manual. Many modern stoves have a built-in air wash system which brings a flow of air into the firebox from a vent above the glass panel. This is called air washing. The air is immediately forced downwards over the door glass creating a layer of air that “washes” over the glass at all times.

​Avoid slumbering – this can lead to a build-up of creosote not only on the glass but also in your flue. It is important to get your fire burning hot on a regular basis to burn off the creosote.

 

LOAD THE FUEL SO THAT IT DOES NOT TOUCH THE GLASS.

 

HOW OFTEN SHOULD I GET A CHIMNEY SWEPT?

As a homeowner, you should consider maintaining your chimney or fireplace at least once a year, ideally before the beginning of the burning season. If you are planning on using your fireplace regularly starting in the autumn, you should aim to have it cleaned in late summer.   Other factors you need to consider include:

 

• How often do you use it?

• Type of heating system used

• Amount and type of wood species, including water content

• Which way do you light the fire?

 

​WHY DOES MY CHIMNEY SMOKE?

There are different reasons why your chimney may smoke. Below is a list of the most likely causes.

​1. Blocked chimney - Having the chimney swept will either correct the problem or highlight where there is a problem and if there is a blockage

​2. Cold air up the chimney -  If the fire hasn't been lit for a while the air up the chimney can get cold. Cold air is heavy and if the flue isn't heated quickly enough, the cold air will force the smoke back into the room. Initially just burn some newspaper as this will create a lot of heat quickly and move the air upwards

3. Downdraught - This is a flow of air down the chimney resulting in puffs of smoke interfering with the wind flow. This can be solved if a cowl is fitted. One reason for the downdraught could be the chimney stack being built too short and another could be trees, buildings, or other objects.

 

TOP TIP

Wood fires always work most efficiently when they have a good ash bed. So don’t be tempted to empty your stove or clean your fireplace of ash too often.

 

TOP TIP!
Oil Agas and Rayburns should be swept on a 12-monthly basis.

This is a picture of one I did recently that was swept 12 months ago.

You can see all the soot in the flue where I removed the sweep

access point.