What Is Flue Draught?

The difference between atmospheric pressure and the pressure existing in the furnace or flue gas passage of a boiler is termed as draft. Draft can also be referred to as the difference in pressure in the combustion chamber area which results in the motion of the flue gases and the air flow.

How do you test a flue Draught?

1. Visually inspect the draught gauge for signs of damage and/or defect.
2. Ignite a small amount of fuel in the appliance and leave to burn for 20 minutes.
3. Adjust pointer to zero (before each measurement).
4. Position the gauge on a level base or hang upright.

How does a flue draft work?

When a chimney is filled with hot gas, that gas tends to rise because it is less dense than the air outside the house. The rising hot gas creates a pressure difference called draft which draws combustion air into the appliance and expels the exhaust gas outside .

What does a flue Draught Stabiliser do?

A chimney draught stabiliser is a device fitted to a commercial flue system to control the draught of the system to a specific level . They are essential as a stable draught is important to ensure optimal combustion – irrespective of whether you use oil, gas or other solid fuels.

What is natural Draught or chimney Draught?

Natural draught system employs a tall chimney as shown in figure. The chimney is a vertical tubular masonry structure or reinforced concrete. The draught is produced by this tall chimney due to temperature difference of hot gases in the chimney and cold external air outside the chimney. ...

How do I know if my furnace flue is clogged?

Signs of Clogged Flues

If you see rust or water streaking on the vent, flue, or on your chimney, something may be blocking the flue . Moisture builds inside your furnace pipes when the air can’t properly circulate, and this can result in rust. Soot around your furnace is also an indication of a problem.

How can I improve my chimney draft?

1. Have The Chimney Swept. ...
2. Open Any Air Vents Or Windows. ...
3. Fully Open The Damper. ...
4. Leave Glass Doors Open Before Each Fire. ...
5. Prime The Chimney Flue. ...
6. Build A Fire Using The Top-Down Method. ...
7. Use Low Moisture Content Logs. ...
8. Burn Smaller, Hotter Fires.

Can a flue be too big?

When a flue is too big, the chimney can be too cold . Cold chimneys make keeping a fire lit more difficult. They also lead to condensation and possible mold inside the chimney brickwork. They key to making and keeping a great draft in your fireplace is making sure the proper sized flue is installed.

Does a larger flue draw better?

Draft size needs to be correlated to the capacity that the flue can exhaust. The reason that a taller chimney creates a better draft is really rather simple as the higher up in the atmosphere the chimney reaches , the greater the differential pressure.

How do you slow down a chimney draft?

If you’re finding that your chimney is drawing too well on your fireplace, a fireplace damper can be used to help reduce the draft and therefore the air supply to the fire. If your fireplace has a damper is will typically at the top inside of your open fireplace, at the base of the chimney.

Where is the draft diverter located?

The draft diverter is situated above the primary flue and regulates the direction and amount of air flowing in and out of the burner.

What is a natural draught flue?

An effective natural draught (or atmospheric) flue will rapidly establish draught conditions that allow safe elimination of products of combustion, and avoid excessive spillage of products of combustion into living spaces.

What are the disadvantages of natural draught?

• Maximum pressure available for producing draught by the chimney is less.
• Flue gases have to be discharged at high temperature since draught increases with the increase in temperature of flue gases.
• Heat cannot be extracted from the flue gases for economizer, superheater, air pre-heater, etc.

What are the limitations of chimney draught?

1. The maximum pressure available for producing natural draught by chimney is hardly 10 to 20 mm of water under the normal atmospheric and flue gas temperatures. Limitations 3. As there is no through mixing of air and fuel in the combustion chamber due to low velocity of air therefore combustion is very poor .

How do you know if your flue is blocked?

1. An excessive smell of smoke during a fire.
2. A white residue on the walls of the flue liner.
3. Water leakage.
4. Debris falling towards the base of the fireplace.

Do all furnaces have a flue?

If your furnace has an AFUE rating below 90 percent , it will most likely have a flue pipe that goes up through your roof. ... If your furnace has an AFUE rating of 90 percent or above, it will have a flue pipe that goes out of the side of your house.