How to find your boiler's model and GC number

Last checked 21/10/2026

To find the right manual or understand a fault code, you need to know your exact boiler. A brand name isn’t enough. Two boilers from the same maker can use different codes and parts. Here’s how to find the details in a couple of minutes.

What you’re looking for

1. The make. This is the maker’s name, such as Worcester Bosch, Vaillant, Baxi or Ideal.
2. The model. This is the full name of your boiler, such as “Greenstar 4000” or “ecoTEC pro 28”. Include any numbers and letters.
3. The type. Is it a combi, a system boiler or a regular (heat-only) boiler? The model name often tells you.
4. The GC number. It’s a seven-digit number, written like this: 47-019-10.

What a GC number is

GC stands for Gas Council. Each GC number points to one model of gas appliance. Engineers and parts suppliers use it to find the exact parts and manuals for your boiler.

Here’s a real example. Glow-worm’s Ultracom2 30cxi combi has the GC number 47-019-11. The Ultracom2 18sxi system boiler has 41-019-13. The two boilers look alike. The GC numbers show they’re different models.

Where to find the details

Look in these places, in order:

• The front of the boiler. The make and model are often printed on the front panel or the control panel.
• The data label. Most boilers have a sticker with the model, GC number and serial number. It’s often under the boiler, or behind a flap or drop-down cover on the front. Only open covers that are meant to open by hand. Never take off the main case.
• The user guide. The model and GC number are usually on the front page.
• The Benchmark checklist. It’s at the back of most installation manuals. Your installer fills it in, and it lists the boiler details.
• Old paperwork. Gas safety records, service records and the original quote all usually show the model.

Still can’t find it? Ask your engineer at your next service. They know where each maker puts the label. You can also contact the maker. Give them the serial number or a photo, and they can tell you the model.

Take a photo of the data label with your phone. Then you’ll have the details to hand next time.

Why it matters

• Manuals. Makers list their manuals by model name. With the right name, you’ll find the right guide fast.
• Fault codes. A code like F.28 can mean different things on an old boiler and a new one.
• Engineer visits. If you tell the engineer the model and the fault code, they can bring the right parts. It can save a second visit.
• Warranty. The maker will ask for the model and serial number when you register or claim.

Next steps

Once you know your make, find it in our boiler brands A–Z. Each brand page links to the maker’s own manuals. If your boiler shows a code, see what your boiler fault code means.