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Underfloor heating water installation

• Underfloor heating water Pipe distance for concrete floor is c/c 200 mm to c/c 300 mm and for timber suspended floors c/c 200 mm.
• Underfloor heating water Pipe to be 100 mm from the walls. Always go with flow to the cold spots first. See hand sketch for typical layout. Max loop length is 110 m.
• Max loop length is 110 m. If the pipe comes in a 200 m coil, it is sometimes much easier to work with the pipe if cut in half, ie 2 pcs of 100 m coils. Also we recommend two people for fitting the pipe, one person that holds the coil and another person to clip the pipe into the insulation.
• Fix the Underfloor heating water pipe to the insulation with the clips provided. You need approximate 1 to 2 clips per metre of pipe.
• The manifold and control pack should always be located centrally in the building.
• The TP5000 room thermostat timer controls the pump. Note, see system layout provided in this document for typical layout. Also, see wiring diagram provided. The system needs to have independent control from the boiler, ie S-plan system.
• Try to use all the pipework supplied. You will usually have waste. The pipe is marked every metre so you know when it is time to go back to the manifold. The 50 m and 100 m loops on the hand sketch are only rough estimations on what you will use.
• Underfloor heating water Pipe is normally not laid under Kitchen and Utility units.
• We recommend that you first install the manifold and the control pack as instructions provided. To fit the pipe to the manifold, cut the pipe end squarely using the plastic pipe cutter. Re-round the pipe end with the calibration tool provided, place the nut over the pipe, then the olive and finally push in the insert into the pipe and then attached to the manifold. The manifold is normally fitted 1 m above the floor level.
• If the pipe is kinked when bending, the pipe should be straightened and rearranged so that the location of the kink remains in a straight length.
• Note the lengths of pipe fitted to each circuit, pipe is marked every metre.
• Note also the room, which each circuit applies.
• Prevent people from walking over the pipes, keep tools etc away from the pipes.
• Fill the system as instructions provided. Do not fill from the boiler filling loop.
• It is important to purge the pipework from the boiler to the manifold, to avoid air being introduced into the Underfloor heating water system.
• Hardwood timber flooring must be conditioned before fixing.
• Screed or chipboard flooring should be laid immediately after the pipe laying to protect the pipe.
• Balance the loops as suggested in the instructions.

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.

 

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