vita compact radiator


Take a look at our frequently asked questions for more information about our products, ranges and services

What does P1, K1, P+, K2 & K3 mean?

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P1 also known as Type 10, is a type of radiator with 1 radiator panel and no convection fins.

K1 also known as Type 11, is a type of radiator with 1 radiator panel and 1 set of convection fins.

P+ also known as Type 21, is a type of radiator with 2 radiator panels and 1 set of convection fins.

K2 also known as Type 22, is a type of radiator with 2 radiator panels and 2 sets of convection fins.

K3 also known as Type 33, is a type of radiator with 3 radiator panels and 3 sets of convection fins.

When do I need to use Low Surface Temperature radiators?

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LST radiators are an ideal choice wherever high efficiency heating is required, yet where safety demands a low surface temperature i.e. where people may injure themselves if left in contact with a standard radiator. The range of Stelrad LST radiators reach a maximum 43°C and are ideal for residential homes, hospitals, schools, nurseries and children’s bedrooms.

How do I calculate the heating requirements of a house/room?

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It is an important and sometime complex calculation when determining what size radiator is required to heat a room to the correct level. STARS (Stelrad Technical Advanced Radiator System) heatloss calculator offers a simpler way to get sizing of radiators right, first time. Both fabric heat loss and ventilation heat loss is also calculated in order to establish the radiator output and size required.

Stelrad measure output in Btu/hr, British Thermal Unit per hour which is the standard measurement used to state the amount of output of any heat generating device. Heat output can also be measured in Watts, 1 watt is equivalent to 3.412 Btu/hr.

Do you run CPD (Continuing Professional Development) courses?

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Stelrad are proud to offer RIBA (Royal Institute of British Architects) and CIBSE (Chartered Institute of British Service Engineers) accredited CPD (Continuing Professional Development) training sessions.

Learn about the latest developments in radiators with a CPD training session led by a fully qualified specialist from Stelrad. The one-hour training session counts towards your 35 hour annual CPD requirement and can be arranged for you on a one-to-one or group basis at your practice, at a time to suit you.

To find out more about the CPD courses on offer click here, or to discuss further call 01709 572201 or email

Where can I find Stelrad BIM products?

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Stelrad has invested in several core ranges designed in the format for Building Information Model (BIM), to download click hereSpecifying Stelrad has never been so easy, simply select the product, drag into your document and drop.

How can I order a radiator brochure?

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You can download the full Stelrad Radiator book from the downloads page. You can also contact us to request a hard copy brochure.

What is your product warranty?

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Most horizontal steel panel radiators come with a 10 year warranty, the Softline has a 15 year warranty but all other radiators have a 5 year warranty.  The warranty covers any defect that is attributable to a manufacturing, assembly or material fault only, further details are available on request or download our warranty statement for full details.

Which radiators come in colour?

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Stelrad radiators are available in white as standard with a 60% gloss finish; the white is RAL 9016. RAL is a European wide colour matching system.

Each Stelrad radiator is subjected to a multi stage cleaning process before the paint is applied. This involves several rinsing stages, including an iron phosphate and demineralisation rinse. The first coat of paint is applied by electrophoresis and the radiator is then stoved and cooled. The second powder coat is applied and the radiator goes through a final curing stage. It is then allowed to cool, prior to packaging.

Stelrad also offers specific radiators in a variety of colours. Please note that once ordered, coloured radiators cannot be cancelled.

The colours shown on this website and in the Stelrad Radiator Book are reproduced as accurately as the process will allow and can be made to order on the identified products only. To request individual colour swatches, please complete the online request form here.

Where can I buy Stelrad Radiators, spare parts and touch up paint from?

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Stelrad supplies these products to all major plumbers’ merchants, to find your nearest stockist click here  or you can purchase directly from us through the website by clicking here 

Do you bend radiators to fit a room?

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Stelrad does not bend radiators, and if this is done your warranty will be invalidated.

What does Δt mean and should I use Δt50?

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Δt refers to the difference in temperature between the water circulating in the central heating system and that of the ambient temperature. It is important to use the correct Δt when selecting your radiators, as the same radiator will have different outputs at different water temperatures due to the heat source.

Δt50 is the UK standard for domestic gas boilers, however Stelrad also quotes at Δt30 and Δt40 for lower water temperature systems, such as renewable systems.

What clearances should I leave around my radiator to ensure maximum efficiency and air flow?

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Stelrad recommends clearances of 100mm either side, 150mm above and 150mm minimum from the floor to the base of the radiator. This allows adequate airflow when the radiator is placed on the bracket.

Which LSTs come with a TRV and lockshield valve?

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The LST Plus Vertical and LST iPlus all come with the TRV and lockshield valve factory fitted, as standard.


What does TBOE/BOE mean?

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TBOE / BOE refers to which position the pipes are connected to the radiator, OE means opposite end i.e. 1 pipe on each side, TB is top bottom i.e. 1 pipe is connected to the top and 1 to the bottom, B is both pipes connected to the bottom.

What pressure are your products tested to?

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Most models are high pressure tested to withstand 188 psi (13 bar). Strictly controlled independent laboratory testing ensures that all Stelrad radiators are guaranteed to perform to a maximum working pressure of 145 psi (10 bar) at a maximum temperature of 95°C. All Stelrad radiators conform to BS EN 442 – the European Standard for radiators.

What connections do your radiators have?

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The standard piping connections for all Stelrad products are ½ inch bsp.  A 3/4 inch valve adaptor is also available, providing a ¾ inch connector option to the valve without reducing performance.

For specific air vent and blanking plug requirements, please click herePlease note the Radical has different connections.

What is included in the radiator packaging for installation?

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Everything required for installation can be found within each radiator’s packaging. Brackets are of a strong design, with open top and deep slots, which facilitate easy and secure installation. Plastic inserts seat the radiator precisely on the bracket, minimising expansion and contraction noise.

The neat nickel-plated plug and vent provide a watertight joint, whilst complementing the superior finish. To facilitate easy one off replacement, nickel-plated brass extension pieces are also available, complete with sealing washer, in 20mm, 30mm and 40mm options.

Which of your products can I fit feet on?

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All steel panel type radiators, including K3, Classic Column and Concord have optional feet, however these must be specified when ordering.

What is the difference between Compact and Elite radiators?

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The Elite is the basis of most of our steel panel radiators. The Compact is basically an Elite with side panel and top grilles fitted.

How do you bleed a Stelrad radiator?

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You can follow the simple step by step instructions by using the following link to download the ‘How to bleed a radiator’ advice sheet or click here to watch a short video on how to bleed a Stelrad radiator.

What is the best way to prevent corrosion in your radiator?

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Firstly a well designed and commissioned system is assumed.

Rusting of iron is a complex but well understood process and requires the presence of 3 ingredients; iron (present in all steel alloys), water and oxygen. Rust is hydrated iron oxide.

The first step in a closed central heating system is to focus on the oxygen component. A well designed and commissioned heating system will initially have dissolved oxygen in the system water which will produce rust. By preventing the addition of new air (air ingress) to the system then the cycle of rust production is limited. Clearly the continued addition of new air to a system will exacerbate the rust production cycle. This must be prevented in the first place and a de-aerator will help remove new air in the undesired event it is introduced.

Secondly the production of rust deposits in a system (often resulting in a sludge known as magnetite) will cause a concentration of corrosion locally / in the area that the sludge is deposited. Therefore the fitting of a magnetic filter may prevent the local build ups of sludge and therefore alleviate concentrated / localised corrosion.

Not mentioned is a good system inhibitor. These are effective because they interrupt the part of the chemical process that allows dissolved oxygen to combine with the iron content of the steel and ‘inhibits’ the production of hydrated iron oxide. A layer (film) of inhibitor is formed over the steel of the radiator. A good inhibitor will also contain ingredients that will prevent the formation of biological contamination which can introduce new oxygen or carbon dioxide to the system. The effectiveness of the inhibitor can be significantly reduced if the protective layer is disturbed respectively by the circulation of air and / or system debris (including magnetite) in the system. Therefore the prevention of air ingress / removal of air will ensure the action of any inhibitor. Additionally the prevention of any magnetite deposition (sludge) via a magnetic filter will also ensure the action of the inhibitor.

How do you clean a Stelrad radiator?

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You can follow the simple step by step instructions on how to clean a Stelrad Elite by using the following link to download the ‘Cleaning a Stelrad Elite radiator’ advice sheet

How do you fit a Stelrad radiator?

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Installing a Stelrad radiator is simple, you can view how these can be done on the following link

Who stocks Stelrad Radiators?

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There are many plumbers’ merchants who stock our products, to find your nearest stocking branch click here

Where are Stelrad radiators made?

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To find out more about Stelrad, please click here

What are the delivery charges when purchasing online?

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Click here to find all the answers to this question.

Will my radiators be all right if I change my boiler to an air source heat pump.

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Your existing radiators should have been sized to suit the existing boiler installation, if you are changing the boiler to an air source heat pump or similar then the existing radiators will still be alright but will need checking to see if they are adequately sized for the new heat source, this can be conducted by the installer or competent person.

If I change my radiators now, will they still work with if I change my boiler to an air source heat pump.

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If you are changing your radiators now, they will be sized to suit your existing boiler installation, if later you change your boiler installation to an air source heat pump or similar the radiators will still work, however as they should have been sized for the existing boiler installation these may need checking to see if they are adequately sized for the new heat source.
If you are contemplating changing your boiler to an air source heat pump or similar at a later date you may want to discuss this with an installer or competent person to size the radiators for the future installation of an air source heat pump or similar.

What temperatures should I work to, to size my radiators.

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When sizing radiators it is advisable to consult with a competent installer to determine what temperatures your heat source works at, you will also need to know the desired room temperature you require, for the radiators to heat the room to.

Which radiator valves should I use.

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It is advisable to use a Thermostatic radiator valve and lock shield valve on radiators, certain radiators can be installed with a centre tap Thermostatic radiator valve and Lock shield valve combined, with many radiators requiring a single Thermostatic radiator valve and lock shield valve.

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