Plastic Back Box (Plenum Boxes) Top Entry
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Delivery and Warranty
Standard UK Mainland Delivery
If you are not in a rush, then we offer standard delivery and your order should be with you between 2-3 working days.
£6.95
Next Working Day Delivery
Place your order before 12pm Monday to Thursday and receive your order the next working day. Orders placed on Friday before 11am will be processed and delivered on Monday. (Excludes Sunday’s and Public Holidays)
£15.95
Nominated Day Delivery
We know sometimes you will need an order on a particular date in the future. Simply select this option at checkout and add what date you would like to receive the order. We will then contact you to confirm the date. If you need to change this order date then please contact us ASAP.
£15.95
Northern Ireland Delivery
We offer a flat fee rate for Northern Ireland orders, and all are 5-7 working day lead times.
£29.95
Scottish Highlands & Islands Delivery
We only offer a flat fee rate for Scottish Highland & Islands orders, and all are 5-7 working day lead times.
£45.95
Channel Islands Delivery
We only offer a flat fee rate for Channel Islands orders, and all are 5-7 working day lead times.
£45.95
Product Details
Specifications
Product specifications
| Type | Plenum box (plastic back box) |
| Entry | Top entry (spigot on top) |
| Square face sizes | 150 to 550mm |
| Spigot sizes | 100 to 315mm diameter |
| Function | Connects circular duct to square grille or louvre |
| Material | Plastic |
| Warranty | 1 Year Manufacturer |
Summary
See more specification See less specification
The Plastic Back Box, also known as a plenum box, is a top-entry box that connects a circular duct to a square grille or louvre. Its durable plastic construction fits standard duct sizes and makes installation straightforward.
- Connects a circular duct to a square grille or louvre
- Top-entry spigot for the round duct
- Durable plastic construction, easy to install
- Smooths airflow behind the grille
- 15 combinations of square face (150 to 550mm) and spigot (100 to 315mm)
Suitable for
- Joining round ductwork to square grilles and louvres
- Homes and commercial buildings, behind ceiling or wall terminals
Installation
Fits behind the grille or louvre, with the circular duct connecting to the spigot on the top of the box. Match the square face to the grille size and the spigot to the duct diameter.
Specifications
| Type | Plenum box (plastic back box) |
| Entry | Top entry (spigot on top) |
| Square face sizes | 150 to 550mm |
| Spigot sizes | 100 to 315mm diameter |
| Function | Connects circular duct to square grille or louvre |
| Material | Plastic |
| Warranty | 1 Year Manufacturer |
Product Description
The Plastic Back Box, also known as a plenum box, is a top-entry box that connects a circular duct to a square grille or louvre. Its durable plastic construction fits standard duct sizes and makes installation straightforward.
- Connects a circular duct to a square grille or louvre
- Top-entry spigot for the round duct
- Durable plastic construction, easy to install
- Smooths airflow behind the grille
- 15 combinations of square face (150 to 550mm) and spigot (100 to 315mm)
Suitable for
- Joining round ductwork to square grilles and louvres
- Homes and commercial buildings, behind ceiling or wall terminals
Installation
Fits behind the grille or louvre, with the circular duct connecting to the spigot on the top of the box. Match the square face to the grille size and the spigot to the duct diameter.
Specifications
| Type | Plenum box (plastic back box) |
| Entry | Top entry (spigot on top) |
| Square face sizes | 150 to 550mm |
| Spigot sizes | 100 to 315mm diameter |
| Function | Connects circular duct to square grille or louvre |
| Material | Plastic |
| Warranty | 1 Year Manufacturer |
Delivery & Returns
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What is a plenum box for?
It connects a circular duct to a square grille or louvre, joining the two neatly while smoothing the airflow.
Where does the duct connect?
To the round spigot on the top of the box (top entry).
What sizes are available?
15 combinations of square face (150mm to 550mm) and spigot diameter (100mm to 315mm).
What is it made from?
Durable plastic.
How do I choose the right one?
Match the square face to your grille or louvre size, and the spigot to your duct diameter.
Where can it be used?
In homes or commercial buildings, behind ceiling or wall grilles and louvres.