Regular boiler
Also called heat-only or conventional. A cylinder plus cold water tanks in the loft.
Best for: Older homes with low mains pressure, or where the pipework is built around it.
Read more →System boilers · Purley CR8
System boiler installation in Purley
Purley’s larger houses often have 2 or 3 bathrooms, and plenty still run on a regular boiler with tanks in the loft. For many of them a system boiler with a cylinder is the natural next step: stored hot water for several showers, without the heating tank in the loft.
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Purley homes
Why system boilers suit bigger Purley houses
Many of Purley’s 1920s and 1930s detached and semi-detached houses have 2 or 3 bathrooms. A single combi often can’t keep up when more than one shower is running, because it heats water as it flows. A system boiler heats a cylinder of stored water instead, so several outlets can draw from it at once.
If you have a regular boiler and loft tanks now, a system boiler is a smaller change than a combi conversion. A cylinder stays in the airing cupboard, old or new, and the heating side is sealed, so the small expansion tank in the loft goes.
For the job in general see system boiler installation. Our Purley area page covers repairs and servicing in CR8.
Before and after
From loft tanks to a system boiler
Left: the regular boiler, cylinder and loft tanks many Purley houses have now. Right: a system boiler with the pump and expansion vessel built in.
System boiler
Heats a hot water cylinder, usually in an airing cupboard. Mains-fed, so no loft tanks.
Best for: Bigger homes with two or more bathrooms in use at the same time.
Read more →The work
What changes when you go from regular to system
Expansion tank out
The small feed and expansion tank in the loft is no longer needed once the heating is sealed and pressurised.
Cold water tank: it depends
With an unvented cylinder it goes too. With a vented cylinder it stays to feed the hot water.
Cylinder kept or replaced
An old, slow cylinder is worth replacing while the system is drained. A newer one may be reused.
System cleaned and pressure-tested
A sealed system runs at higher pressure than an open-vented one, so we flush it and check the radiators and valves before it goes live.
Controls to Boiler Plus
Time and temperature control for heating and hot water, with zones if your house needs them.
The cylinder choice
Vented or unvented?
Unvented
Fed straight from the mains, so showers are at mains pressure in every bathroom. Needs a good incoming flow and a G3-qualified installer, which we’ll confirm on your quote.
Vented
Fed from the cold water tank in the loft, as now. Works whatever the mains is like. Showers rely on gravity or a pump.
Which suits you
It comes down to your mains flow and how you want the showers to feel. We measure the flow before recommending either.
On the day
Access and parking in Purley
Hills and driveways make parking easy at most Purley houses, which helps when a cylinder is coming in and tanks are coming out. Around the town centre, allow for pay-and-display and let us know in the quote form.
If you live in one of the flats near the station, a system boiler is unusual. Most have a combi in a kitchen cupboard, and our combi boiler installation page covers those.
Installation day
What happens while we’re there
A like-for-like replacement is usually done in a day. Conversions and moving the boiler add a day or two, and we’ll tell you the plan in advance.
- 01 · Arrival
Dust sheets down, water and gas off
We protect floors and the route to the boiler, then isolate the gas, water and power.
- 02 · Morning
Old boiler out
The old boiler is drained and removed. If tanks or a cylinder are going too, they come out now.
- 03 · Midday
System cleaned
The radiators and pipes are flushed so the new boiler starts on clean water.
- 04 · Afternoon
New boiler, flue and filter in
The new boiler goes up with its flue, filter, condensate drain and controls, and the pipework is tidied.
- 05 · Commissioning
Tested and set up
Gas tightness and combustion are checked with an analyser, inhibitor is added and the flow temperature set for efficiency.
- 06 · Before we leave
Shown how it works
A walk-through of the boiler and controls, the Benchmark checklist handed over, and the warranty and Building Control paperwork underway.
System boiler installation nearby
FAQ
System boiler questions from Purley
Is a combi right for a big Purley house?
It depends on bathrooms more than bedrooms. With 2 or more showers used at once, a system boiler and cylinder usually serves better. We’ll check your water flow and recommend honestly.
Can I keep my loft tanks?
You can keep the cold water tank if you choose a vented cylinder. The small expansion tank goes either way once the heating is sealed.
How long does a regular to system change take?
Longer than a straight boiler swap, because the loft pipework changes and the system is sealed. A new cylinder adds time too. Your quote will say how many days.
Do you cover Kenley and Foxley?
Yes, all of CR8 including Purley town centre, Foxley, Russell Hill and Kenley, plus Sanderstead and Coulsdon.
What if I still have a back boiler?
Then it’s a bigger job, as the boiler moves out of the fireplace. See back boiler replacement in Purley.
Guides
Read before you decide
- Choosing a boilerCombi vs system vs regular boiler: which is right for your home?Combi, system or regular boiler? How each one works, which homes each suits, and when changing type makes sense. A plain guide from Gas Safe engineers.Read the guide
- Choosing a boilerCombi boilers: water pressure and flow rate explainedWhy your mains water flow rate matters for a combi boiler, the difference between pressure and flow, a simple home test, and what to do if it’s low.Read the guide
- InstallationHow long does a boiler installation take?How long does a new boiler installation take? Like-for-like swaps are usually done in a day, moves and conversions take 1 to 3 days. What makes a job longer.Read the guide
Everything we do
New boilers
Conversions
Repairs & servicing
Price a system boiler in Purley
Tell us how many bathrooms you have and whether there are tanks in the loft.