Finding Your Own Jet Sizes for Your Cooker or Hob

If you’re trying to replace your cooker or hob injectors, convert between natural gas and LPG, or simply confirm what jets you already have fitted, the good news is that you can normally find your own jet sizes without needing to contact the manufacturer. You just need to know where to look.

This guide shows you the two easiest ways to identify your jet (injector) sizes:

• Checking your appliance manual for the injector table
• Reading the numbers stamped on your existing jets

Either method will tell you the exact sizes you need.

1. Finding Jet Sizes in Your Appliance Manual

The most reliable source of injector information is your cooker or hob’s user manual. Almost all manufacturers include a dedicated section called the injector table.

What the Injector Table Shows

This table lists the exact jet sizes for every burner, usually in two columns:

• Natural Gas (NG) injector size
• LPG injector size

If your appliance can be converted between NG and LPG, both sets will be listed.

Where to Find the Table

You can normally find it in:

• The printed manual that came with the appliance
• A PDF version on the manufacturer’s website
• The “Installation” or “Technical Information” section

In a PDF, use the search box and type words like:

• injector
• nozzle
• jet
• LPG
• NG

What an Injector Table Looks Like

Once you’ve found your table, simply match your burners to the sizes listed.

2. Checking the Numbers on Your Existing Jets

If you don’t have the manual, you can still find your jet sizes by checking the jets that are already fitted.

Where the Jet Number Is Located

Remove the burner cap and burner head. Underneath, you’ll see a small brass injector. On the face of that injector is a number such as:

• 50
• 65
• 70
• 87
• 100
• 120
• 150

That number is the orifice size in hundredths of a millimetre.

How to Interpret the Number

• 50 = 0.50mm (Usually LPG small burner)
• 67 = 0.67mm (LPG medium burner)
• 87 = 0.87mm (LPG large burner)
• 120 = 1.20mm (Natural gas burner)

To replace jets, just match the same numbers.

To Convert Between Fuels

• NG → LPG: You will need the smaller LPG sizes
• LPG → NG: You will need the larger NG sizes

This is why finding your injector table or reading your stamped sizes is essential.

If You Can’t Find the Manual or Stamped Numbers

If the manual is missing and your jet numbers have worn off, you can still work out what you need by:

• Identifying your cooker model number
• Searching the model number online for a downloadable manual
• Contacting us with your appliances model number
  

Most brands follow similar sizing patterns, so even without a manual, the correct sizes can usually be determined.

Safety Notice

You can find your own jet sizes, but a Gas Safe registered engineer must always install or replace injectors in the UK.

Once You Know Your Sizes

Once you’ve found your jet or injector sizes, you can buy the exact replacements or a full conversion kit to match your appliance and fuel type.