Gas Safe registered 25 years in the trade 12 years running the business
How a system boiler and cylinder work together
A system boiler heats your radiators and also heats a store of water held in a cylinder, usually in an airing cupboard. When you open a hot tap, the water comes from that store rather than being heated on the spot. The pump and expansion vessel live inside the boiler casing, which keeps the setup tidier than an older regular boiler, and there is normally no need for a cold water tank in the loft.
Because the hot water is already waiting, several outlets can draw on it together without the flow dropping off the way it can with a single combi. The trade-off is space for the cylinder and the fact that once the stored water is used, it takes a while to reheat. A cylinder that is sized to your household keeps that from becoming a problem day to day.
Homes that suit a system boiler
We tend to recommend a system boiler where hot water demand is high or spread across the house. Typical examples include:
More than one bathroom, or a bathroom plus an en suite
Families where showers often run back to back or at the same time
Homes with a large bath that is filled regularly
Properties where mains flow is fine but a combi would be stretched
Like-for-like or switching to a combi?
If you already have a system boiler and a cylinder in good order, replacing the boiler like-for-like is often the most sensible choice. The pipework layout is already designed around it and you keep the strong hot water supply you are used to. Chris will look at the age and condition of the cylinder too, since there is little point fitting a new boiler to a cylinder that is close to the end of its own life.
Some households find their needs have shrunk, perhaps because children have moved out, and would rather have the cupboard space back. In that case a combi boiler installation may suit you better. Our combi vs system boiler guide sets out the differences side by side, and Chris will give you his honest view during the survey rather than steering you towards whichever job is bigger.
What the survey covers
Every system boiler quote starts with a free visit. Chris checks the cylinder: its size, its age, whether it is vented or unvented, and how it is insulated. He looks at the space available in the airing cupboard and around the boiler position, the route of the flue and the condensate pipe, and the size of the gas supply from the meter.
He will also look at the heating and hot water pipework, the pump arrangement on the existing system and the controls. A system boiler works best with a proper programmer and room thermostat, and many homes benefit from separate timing for heating and hot water so the cylinder only heats when you need it. All of that is written into the quote so you know exactly what is included.
Cylinder size, type and condition
Space for the boiler and cylinder
Pipework, pump arrangement and gas supply
Heating and hot water controls
Installation day and handover
Installation is carried out by Chris and his son, a second-year apprentice. Chris has 25 years in the trade and has run C Gill Plumbing & Heating for the last 12, and we are Gas Safe registered. On the day we protect the area, drain the system, remove the old boiler and fit the new one, connecting it to the cylinder, the heating circuit, the gas and the flue. If a new cylinder is part of the job, it is fitted at the same time.
Once everything is filled and running, we test the boiler, check that the cylinder heats and the radiators warm evenly, and set the controls. Before we leave, we walk you through the timings for heating and hot water. After that, a yearly boiler servicing visit keeps the system in good condition, and we are happy to do that for you. For more on how we handle every replacement, see our boiler installation page.
Book a system boiler survey
We cover roughly 30 miles from Briton Ferry, including Neath, Port Talbot, Swansea, Bridgend and Llanelli. Call 07429 632804, send a WhatsApp, or use the form on our contact page. We are available Monday to Friday 8am to 8pm and Saturday 8am to 6pm, and every quote is free with no obligation.
Common questions
System Boiler Installation FAQs
Clear answers before you arrange a visit.
What is the difference between a system and a regular boiler?+
Both store hot water in a cylinder. A system boiler has the pump and expansion vessel built in and normally needs no loft tank, while a regular boiler relies on a cold water tank and separate parts.
Do I need to keep my hot water cylinder?+
With a system boiler, yes, the cylinder is part of how it works. If you would rather lose the cylinder, a combi may suit you, and Chris can advise on whether that would work in your home.
Is a system boiler better for two bathrooms?+
Often, yes. Stored hot water lets two showers run together more comfortably than a single combi, though the cylinder needs to be the right size for your household.
Can you fit a new cylinder at the same time?+
Yes. If your current cylinder is old, too small or in poor condition, replacing it alongside the boiler can be included in the quote.
How do I book a survey?+
Call 07429 632804, WhatsApp us or fill in the contact form with your postcode, and Chris will arrange a time to visit. The survey is free.
