Can you put an elbow on a boiler flue?

Author: Catharine Huels II  |  Last update: Monday, June 2, 2025

Can I put flue elbows straight on top of the boiler? Elbows for offsetting can be fitted directly into the flue turret, or high level adapter on all our wall hung boiler variants. There is no requirement for running any straight flue length between them.

Can a boiler flue have bends?

Nevertheless, some boiler models allow for longer boiler flues which sometimes require bends. The number of bends allowed depends on the length of flue allowed.

Can you have a 90 degree bend in a flue?

If bends are unavoidable, then there must be no more than four bends in the length of the chimney. A bend should be no more than 45 degrees from the vertical, with the exception that 90-degree factory-made bends or tees may be treated as two 45-degree bends.

Can you put an elbow in a vent pipe?

Plumbing vents can have elbows and be installed horizontally or at an angle. Properly installed plumbing vents should not leak and prevent slow draining, gurgling sounds, and sewer gas odors.

Can I put an extension on my boiler flue?

Flue extensions are brand specific and must be the same brand as the manufacturer of the flue piping system that is being extended. The range covers the most popular brands, lengths and sizes. This must be situated at least 30-60cm from a window or door, preventing harmful gases re-entering the property.

boiler flue installation tips that no one asked for

What happens if you block a boiler flue?

If your boiler's flue becomes blocked, these gases have nowhere to go other than back inside your home. In some cases, this can be fatal, with the NHS stating that around 60 deaths a year are caused by carbon monoxide poisoning.

How much does it cost to extend a boiler flue?

Extending your boiler flue in this way typically costs around £75 – £125 per m. This includes both supply and installation, as well as the cost of creating a new hole for the flue to exit your home.

Can you put a 90 in a vent pipe?

Vent pipes that release sewer gases and maintain proper water pressure may incorporate bends or 90 degree elbows to navigate obstacles and connect to fixtures like sinks.

Can you put an elbow on a stove pipe?

【Elbow Connection】Stove pipe elbow is designed with elbow connection, allowing you to rearrange the previous pipe to turn or fit in a limited space. You can combine a 90-degree stove pipe elbow with a straight pipe to change the direction of the smoke.

Can you have bends in a vent pipe?

In conclusion, while plumbing vents are traditionally designed as straight pipes, bends are permissible under certain conditions. Proper planning, adherence to local building codes, and maintaining the required slope are crucial factors when considering bends in plumbing vents.

Can a boiler flue be angled?

A flue duct outlet can be angled away from the boundary so that the distance between the outlet and the boundary can be maintained to at least 600mm, provided that the shortest distance between the terminal and the boundary is not less that 300mm (see Figure 1 opposite).

What are the rules for flue bends?

If bends are necessary there must be no more than four in the length of the chimney. The angle of the bend should be no greater than 45° from the vertical, with the exception that 90° factory made bends or tees may be treated as being equal to two 45° bends.

What is the pressure loss of a 90 degree bend?

Designers usually apply the general rule that a 90" elbow bend has a pressure drop equivalent of 30 to 50 pipe-diameters length of straight pipe [207].

How many elbows can a boiler flue have?

General Positioning Guidelines. Boiler flues should be installed with specific distances and angles in mind. Vertical flues have a limit on how far they can travel, often defined by the manufacturer. Every bend in the flue reduces this distance, so a six-metre flue can only use four metres and two bends.

What are the rules for boiler flue?

What are the regulations around boiler flue?
  • 300 mm away from an opening window or air vent.
  • 25 mm below guttering, drain pipes or soil pipes.
  • 300 mm above the ground, roof or balcony level.
  • 2,000 mm below a Velux window.
  • 1,200 mm from an opening, such as a door or window, into the home.

What are the rules for boiler venting?

The flue gas exit of the venting system must be at least three (3) feet above the point at which it passes through the roof and at least two (2) feet higher than any portion of a building within 10 feet horizontally of its location.

Can you use a 90 degree elbow in a drain pipe?

In drainage the Universal Plumbing Code requires long sweep 90 degree elbows for horizontal direction changes and at the bottom of stacks to go from vertical to horizontal regular 90 degree elbow are only allowed to turn down like in a horizontal to vertical direction change.

How many bends can you have in a stove pipe?

* The stovepipe should be straight as well as short. Use no more than two right-angle bends in the stovepipe installation.

Can a hood vent pipe have an elbow?

A straight, short duct run with limited elbows and transitions will allow the hood or downdraft to work most efficiently. Running ductwork down is fine as long as restrictions are adhered to (length, elbows, distance between elbows, etc.).

Can you put an elbow on a vent pipe outside?

The drain-waste-vent pipe is run vertically and connected to your horizontal pipes. The pipes are run horizontally so that water can flow directly to the city sewer system so don't ever use a tight 90-degree elbow.

Why does a 90% furnace need PVC venting?

These PVC pipes are connected to the furnace and expelled outside. This high efficiency venting system must be installed when you install the new furnace. The PVC pipes are used for air intake, exhaust gas, and to remove the corrosive condensation resulting from the combustion process.

Does a plumbing vent pipe have to be straight?

Vent pipes must be installed so they stay dry. This means that they should emerge from the top of the drainpipe, either straight vertically or at no less than a 45-degree angle from horizontal, so that water cannot back up into them.

Why are boiler flues so expensive?

Vertical boiler flues are often more expensive than a newer round flue, due to the extra parts and work that may be needed to install them. Unless your engineer is extremely tall, installing a vertical boiler flue may need scaffolding to access the area. Other complications could occur also.

Can I install a boiler flue myself?

Only Gas Safe registered engineers can work with boiler flues. This is a legal requirement in the UK to ensure the safety and efficiency of your heating system. These engineers have the necessary qualifications and training to install, maintain, and inspect flues safely.

How far can you extend a boiler flue?

As a general rule, a flue should work effectively when it's up to 10 metres in length. This is usually based on a standard thickness of 60/100mm. For flues that need to be longer than this, it's a good idea to increase the thickness to 80/125mm to ensure that the gases are able to escape easily.

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