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How to Size Your Scale Centurion Unit

It's important to get the right size Scale Centurion unit for your property.

This is because the special anti-scale powder requires sufficient contact time with the water in order to work fully.

(If the water goes through the unit too fast, it won't break anything, it just won't work nearly as well.)

The easiest way to size your unit is by checking your water boiler type - because the boiler has a major impact on your property’s flow rate.

The Three Most Common Water Boilers In UK Properties

Quick Summary

Combi Boiler - You need the Standard Size Unit
System / Unvented Boilers - You need a Larger Unit
Conventional / Gravity fedCheck your flow rate
NEW: Ground Source / Other Green Systems - Check your flow rate

Boiler Details 

1) Combi Boilers 

Aka a Combination boiler or Condensing Gas Boiler

This is a gas fired unit that gives you hot water whenever you turn on the tap. They don’t require a cylinder or water tank.

Combi boilers are the most common boilers in UK households due to their high energy efficiency.

Where are they located? What do they look like?

They often - but not always - sit on the wall in the kitchen.

As you turn on the hot tap you’ll hear a gentle whoosh as the gas lights up - though newer models tend to be silent.

They almost always have a small window where you can see the blue pilot light.

Scale Centurion Size you’ll need:

Because Combi Boilers restrict the flow rate this means you almost certainly only need the smaller Standard Size Unit.

(However if you've got a large property with two combis - or anything unusual like that - then check your water flow rate to make sure it doesn't exceed 16 litres per minute. And don't hesitate to ask us


2) System Boilers

aka Unvented / “Megaflo” Types

These are hot water tanks which store hot water efficiently, ready to serve your bathroom and kitchen hot water taps.

As they run out of water the system heats more water rapidly.

Where are they located? What do they look like?

They’re often found in the attic / loft or an airing cupboard.

Look for a large / usually tall hot water cylinder.

They’ll usually be in newer properties or installed in the past ten years (they’re increasingly popular - and common in new build developments).

They don't need additional cold water tanks - everything is integrated into the one system.

Look for keywords in your boiler name eg “Unvented”, “Cylinder” or “megaflo” (the latter is the most common brand).

Scale Centurion Size you’ll need:

If you have this type unfortunately you need a large 32L Scale Centurion version. This is because the rate at which the water is “sucked” into the expanison vessel can be very rapid - so you need the Larger Unit.

But please don't hesitate to check with us if you're not sure.


3) Conventional / Gravity Fed boilers

These are the old fashioned / traditional, “open vent” / “heat only” boilers.

Where are they located? What do they look like?

They ‘re usually found in older properties.

Look in the loft/attic for a cold water storage tank and hot water cylinder / boiler. (The boiler might be elsehwere in the house eg in an airing cupboard. 

These will heat water slowly. If you’re in a property with several lovely people who take long baths and oh! now there’s no hot water for an hour or three, then you probably have a Conventional boiler

Scale Centurion Size you’ll need:

While this means you have a low-pressure water system you will need to check your water flow rate in the property to make sure you get the right Scale Centurion model.

Don't hesitate to check with us


Ground Source / Other Green Heating Systems

There's a new generation of well engineered / eco solutions coming onto the market to lower human impact on the environment - and to lower bills!

For example ground source and air source systems.

If you have one of these, while this means you probably have a low-pressure water system you will need to check your water flow rate in the property to make sure you get the right Scale Centurion model.

Please don't hesitate to check with us.



Scale Centurion Information

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