Kestrin Underfloor Heating
FAQ
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Frequently Asked Questions

 

Below are some basic Q&A's that may help you with your project, for a detailed explanation of Underfloor Heating and the Wirsbo System please download the fact sheets in the Download section.

Alternatively please feel free to contact our design & technical support department or

e-mail us your technical query.


What s Wirsbo 20?
Why Choose Wirsbo UFH?
Why select a 20mm pipe system?
Is Wirsbo 20 UFH Reliable?
What Type of floor constructions are suitable?
What guarantee does Uponor Housing solutions offer?
What type of insulation is required?
Boiler Size & Heat Outputs
What type of boiler / type of fuel can be used
Is it suitable for wooden floors?
Are all types of vinyl, carpet and underlay okay?
What type of screed is required? What thickness?
Is the pipe affected by heating system additives?
Is it expensive to buy / run?
What happens if the pipe gets damaged?
Is it safe?

 

What is Wirsbo 20?

Wirsbo 20 Underfloor Heating is a complete radiant heating system incorporating a 20mm diameter flexible plastic pipe produced in cross linked polyethylene (PEX) and an extensive range of water and temperature controls for maximum comfort and fuel efficiency. (Back to top)

Why Choose Wirsbo UFH?

Wirsbo developed the unique method of producing its PEX piping in 1972 and was the first UFH system in the UK to be awarded the BBA certification. Manufactured in Sweden to the strictest international standards including ISO9001 Quality Control Standard, and environmental certification EN ISO14001. The pipe has also been assured as compliant with UK Water Regulations by KIWA (Back to top)

Who are Wirsbo?

Wirsbo Systems are an integral brand within the Uponor Group trading in the UK through Uponor Housing Solutions. With hundreds of years of unbroken company history Wirsbo lead in modern warm and cooled water systems design. Wirsbo continues to develop pioneering technology for plastic pipe underfloor and plumbing systems. (Back to top)

Why select a 20mm pipe system?

Wirsbo uses a 200mm pe-PEX pipe to enable the system to be designed at 7.5 degree drop across the heating loops. This minimises temperature differences in the floor and generally means a simple serpentine installation pattern can be used - making it easier to install. The Wirsbo system is typically designed so that pipes are at distances of 300mm - less pipe means the system is quicker to install and costs less. (Back to top)

Is Wirsbo 20 reliable?

Wirsbo have had their plastic pipes both under continuous test and in use for 30 years. Wirsbo hold the world record for durability under high temperatures and pressure. The Agrément certificate for the Wirsbo PEX pipe gives a minimum operating life expectancy of 60 years.(Back to top)

What floor constructions are suitable?

Most new build and refurbishment floor structures are suitable for Wirsbo 20 UFH including concrete or screeded floors; timber suspended floors and 'floating' floors. A very wide range of floor finishes can be used with Wirsbo 20 UFH such as Laminated or natural timber; stone; slate; marble; quarry tiles; vinyl; linoleum or carpet. Dense or thick carpet underlay may restrict heat output from the floor. For more information about floor constructions click here (Back to top)

What Guarantee does Uponor Housing Solutions offer?

Uponor Housing solutions Ltd ("Uponor") guarantees (to the original purchaser/customer) that the pipes and fittings sold by it are free of defects in materials or manufacture under normal conditions of use for a period of 25 years and in case of electrical and mechanical products for 1 year from the date of installation. (Back to top)

What type of insulation is required?

It is essential that floors which are ground bearing or suspended over an un-heated space with or without underfloor heating are properly insulated to meet the U-values requirements as stated in the Building Regulations Part L1/L2 2002. The value is currently set at 0.25 W/m2K. The thickness of insulation required to achieve this will vary according to the type of floor, size of floor and type of insulation selected. Generally, an insulation with a high thermal resistance is preferable, to reduce the build height of the total floor construction. (Back to top)

Boiler Size & Heat Outputs

Boilers are normally sized according to heat load requirement from the heat loss calculation in the normal way and also taking account of other requirements such as domestic hot water. As a guide, the heat output available from a Wirsbo UFH system is 100W/m˛ for a solid floor and 70W/m˛ for a timber suspended or floating floor. (Back to top)

What type of boiler / type of fuel can be used?

Generally any type of boiler or any type of fuel can be used as a heat source. Condensing boilers are certainly worth considering because the low return water temperature often means that the boiler operates in condensing mode. (Note: oil fired boilers may not be suitable where there is a low heat output requirement) (Back to top)

Is it suitable for wooden floors?

In Sweden, Wirsbo’s home country, timber floors are extremely popular and are increasing in popularity in our country. Chipboard floors which form the base for carpet or vinyl finishes can be used without special consideration due to the stability of their construction. Similarly, laminated strips or boards are designed to be unaffected by shrinkage due to moisture changes. Real wood finishes, however, are natural materials and may be subject to shrinkage or expansion as the moisture content of the wood changes. The use of underfloor heating need not cause problems providing wood with moisture content below 10% is selected and correctly stored before use. A marginal change in gapping between boards may be evident between the heating season and when the heating is not in use. (Back to top)

Are all types of vinyl, carpet and underlay okay?

These materials can be laid over screeded or timber covered floors. Maximum floor temperatures for vinyl type materials can be limited to those recommended by the manufacturer but a lower heat output may result. When selecting underlays for carpets, bear in mind that the use of dense or very thick underlays may also restrict the heat output from the floor.(Back to top)

What type of screed is required? What thickness?

There is no special requirement for the screed. For domestic applications, use a fine sand / cement mix (to BS 8204) with a minimum thickness of 65mm. Wirsbo recommends that wherever possible the thickness of the screed is 75mm. No special screed additives are necessary. Anhydryite screeds and other types of flow screeds will not have an adverse effect on the pipe. However, it is very important that you advise us if you have this type of screed in your project. (Back to top)

Is the pipe affected by heating system additives?

Normal additives, such as Fernox and Senitel, will not affect the pipe. The integral oxygen diffusion barrier on the Wirsbo-pePEX pipe limits oxygen permeation through the pipe wall to help prevent oxidation of metal components in the system. This helps to reduce maintenance costs. (Back to top)

Will I be warm enough?

Provided building meets minimum insulation standards as laid down by current Building Regulations, Wirsbo UFH will provide full comfort conditions. Floor temperatures will not normally exceed 29°C which means that the floor will feel comfortable. (Back to top)

Is it expensive to buy / run?

It is a competitively priced system when compared to good quality or special radiators (such as a Low Surface Temperature Radiator), used in certain applications. Independent tests carried out on operating efficiencies suggest that UFH can be up to 26% more efficient than radiators. (Back to top)

What happens if the pipe gets damaged?

If the Wirsbo-pePEX pipe is damaged, it can be restored to its original state by carefully applying heat from a hot air gun to regain the original dimensions. If the pipe is punctured it can be replaced, if accessible, or repaired using a high integrity pipe repair coupling available from Wirsbo. (Back to top)

Is it safe?

Wirsbo-pePEX pipe is perfectly safe. It is non-toxic and can operate at temperatures as low as -100oC to over +100oC and pressures up to 10 bar (approximately 145psi). (Back to top)

 

Kestrin Limited
Landmark House
75 Station Road
Horsham
West Sussex
RH13 5EX

© Kestrin Limited

Tel: 01403 756777
Fax: 01403 756888
email:info@kestrin.co.uk

Uponor WirsboThe Underfloo Heating Manufacturers Association