Most homes have one of three types of boiler: a combi, a system or a regular boiler. The quickest way to tell is to look for a hot water cylinder and water tanks. No cylinder at all usually means a combi. A cylinder but no tanks in the loft usually means a system boiler. A cylinder plus tanks in the loft usually means a regular boiler.
Why it helps to know
Knowing your boiler type helps you understand problems like low pressure or no hot water, and it helps our engineers give you the right advice over the phone. It also matters when it’s time for a replacement, because the right new boiler depends on your current system and how your home uses water.
Check 1: Is there a hot water cylinder?
Look in your airing cupboard, often on the landing or in a bedroom. A hot water cylinder is a large tank, usually copper-coloured or covered in insulation, that stores hot water.
- No cylinder: you almost certainly have a combi boiler. It heats water straight from the mains as you turn on a tap.
- A cylinder: you have a system or regular boiler. Go to check 2.
Check 2: Are there water tanks in the loft?
If you have a cylinder, look in your loft for water tanks.
- No tanks: you most likely have a system boiler. The cylinder is fed directly from the mains.
- A large cold water tank, often with a smaller tank next to it: you most likely have a regular boiler, sometimes called a conventional, heat-only or open vent boiler.
Check 3: Look at the boiler itself
- The name or label. The model name on the front or underneath often includes the word “combi” or “system”. The manual will say too.
- A pressure gauge. Combi and system boilers usually have one, as they run on a sealed system. Regular boilers often don’t.
- The pipes underneath. Combi boilers often have more pipes, including connections for both heating and hot water.
Some older homes have a back boiler, fitted behind a gas fire in the living room. These are now rare and are usually replaced with a modern boiler when they fail.
A quick guide to each type
Combi boiler
Heating and hot water in one compact unit, with no tanks or cylinder. Great for smaller homes and flats, and it frees up space. Hot water flow depends on your mains pressure.
System boiler
Heats your radiators and a hot water cylinder, with no loft tanks. Good for homes with more than one bathroom, as several taps can run at once.
Regular boiler
Uses a cold water tank in the loft and a cylinder. Common in older properties, and sometimes the best fit where mains water pressure is low.
Still not sure?
That’s fine, plenty of people aren’t sure, especially if they’ve recently moved in. Take a photo of your boiler, including the label and the pipes underneath, plus your airing cupboard if you have one. Our engineers can usually tell you straight away. If you’re thinking about a replacement, our boiler installation team can advise whether to keep your current type or switch, and a yearly boiler service keeps whichever type you have running safely.
MS HEATING AND PLUMBING has been fitting and repairing boilers across Birmingham and Solihull for over 29 years. Our engineers are Gas Safe Registered, and we’re a Which? Trusted Trader.
