Underfloor Heating- water

Single Zone by Underfloor Heating Systems

Underfloor heating water installation

If the Underfloor heating water system for some reason makes a noise, then there is probably air in the system. The air can be removed from the end caps on the manifolds, similar to a radiator system. Make sure that the system is operated for 24 hours before making any adjustments.

When the Underfloor heating water system is running make sure that the room thermostats are set at 20 degree C. The pump speed should be on number 3. The mixing valve is normally set on number 3 for concrete floors and number 4 for timber suspended floors. If for some reason the rooms are not getting warm, then it is possible to increase the flow temperature on the mixing valve.

Maximum heat output for Underfloor heating water systems are 100 W/m2 for concrete floors and 70 W/m2 for timber suspended floors. For any Underfloor heating water system to work efficiently the property needs to be built to current building regulations. Carpet and underlay should not exceed 2.5 Tog.

If you are using the Underfloor heating water for a Conservatory, note that it will extend the time you can use the Conservatory for, not to keep it at 20 degree C all year as the heat losses are higher than 100 W/sqm in a Conservatory. Usually, this is also the case with radiators.

Condensing boilers are very efficient with underfloor heating. For combination boilers it is recommended to check with the manufacturer if the boiler can be fitted with a secondary pump. Sometimes if the project is just a small flat and the combi boiler is only providing UFH and hot water, it is possible to have the UFH system without the control unit. There need to be a safety device on the boiler to prevent the end user from adjusting the flow temperature above 60 degree C.

Underfloor heating systems can be mixed with conventional radiator systems. Also note that the underfloor heating system needs to be a complete separate system , ie the flow and return for the underfloor heating needs to go all the way back to the boiler. If you do have radiators in your system, we recommend independent control from the boiler, ie not together with the underfloor heating. See system layout below.

We recommend a minimum of 50 mm of Polyurethane insulation for the underfloor heating system. This is very high quality insulation and can be used for both concrete and timber suspended floor constructions.

Note we do not supply the insulation. Any builder’s merchant will have Celotex or Kingspan insulation in stock. The quote is based on clipping the pipe direct to the insulation board. We do supply pipe clips. We recommend 65 mm of screed on top of the insulation for concrete floors, for timber suspended floors see website or manual.

The screed must be allowed to dry for a minimum of 4 to 6 weeks before the heating is operated. As the system is used for the first time, the mixing valve must be set to minimum setting to let the moisture in the screed to dry out. The temperature should be increased by two degrees every day until the mixing valve is set at 45°C. Floorboards must have moisture content lower than 7 % before they are installed. We do not recommend floorboards thicker than 25 mm, see website link under technical for more information about floorboards. Always check with the manufacturers of any floor finish that it will work with underfloor heating.

For stone and ceramics tiles it is recommended that flexible adhesives and grout are used. Avoid underlays for carpet with felt and rubber crumb type. With Vinyl check the vinyl floor manufacturer that it works with underfloor heating. Laminate flooring should have an expansion gap for movement.

As WC and Bathrooms are very small areas, extra heat might be needed. Therefore it is standard practice to install towel rails in these areas, combined with the underfloor heating.