Chris Simmons, commercial manager for Wavin Underfloor Heating, has the answers.
At what temperature will underfloor heating operate?

The heat output of a UFH system depends on the difference between floor and air temperature in the room to be heated. The difference can be multiplied by 10.6 to provide an approximation of the system heat output in W/m².

Most buildings require heat output between 35W/m² and 75W/m² - requiring floor temperatures of 23-28°C. With concrete floors, this can typically be achieved with water at 35-45°C, with timber floors, however, the water needs to be 45-55°C.

Can UFH be incorporated into an existing heating system and used independently?

All heating systems differ and altering the pipework to change a system to be independent can be a challenge. The key here is to take the UFH supply from before the zone valve to the radiators. If a radiator zone valve doesn't already exist on the heating circuit, one will need to be installed to prevent the radiators activating with the UFH. There are wiring diagrams and system schematics on www.thermoboard.co.uk

Does the UFH system require a special type of boiler?

No, generally any type of boiler can be used but condensing boilers can operate more efficiently when used with UFH than with radiators. UFH is an ideal partner for low temperature renewable heat sources such as ground or air source heat pumps to further reduce fuel bills.

Why do l need to use manifolds?

Manifolds control the heat distributed to each room by balancing the flow rates and heat output of individual circuits to match the heat loss in each room. Room thermostats provide overall heating control, opening and closing valves on the manifold to maintain the desired room temperatures. Mixing manifolds also provides control of the water temperature within the UFH system, allowing fine tuning of heat outputs.

How is balancing achieved?

Basic balancing is adequate for 90 per cent of installations. Installers can use the table in the manifold installation guide to obtain the valve setting for each circuit based on its length.

However, some installations involve rooms with abnormal heating requirements. In these cases advanced balancing can be performed using the return temperature gauges on each circuit and following the instructions in the guide.

A composite manifold has been introduced to the Thermoboard range to provide installers with an effective way to balance a UFH system during installation.

Why should I use a thermostat?

Traditional thermostats often cause confusion as there is multiple wiring involved, making it easier to cross wire a UFH system. The company has developed control systems for simple installation. The standard control centre can be used with both hard wired and wireless thermostats, giving the installer complete flexibility.

The hard wired thermostats are all connected back to the same two terminals on the control centre at first fix stage and then synchronised with the relevant circuit(s) during commissioning. However to avoid any wiring difficulties you can always use wireless controls. Using wireless, heating zones can be created using sensors to vary the temperature throughout the whole house.

What insulation is to be used?

In most UFH projects, polystyrene insulation is used. Insulation type is important: the lower its thermal conductivity, the less heat is wasted. There are two types of polystyrene that can be used; expanded polystyrene (EPS) which has a high conductivity that is increased by the absorption of water; and extruded polystyrene (XPS), a low conductivity, waterproof insulation which has a high compressive strength.

Thermoboard UFH
01392 444122