Tips and Tricks For Trouble Free Underfloor Heating Installation
Picture Perfect
Every underfloor heating system should have a CAD design clearly showing pipe layout, spacings, location of the manifold and also the flow rates. If the design is clear the installer is half way to installing a system that will operate and function correctly.
When first arriving on site the design should be checked against the actual building layout - often site changes are made without all parties being notified. If the design has to be amended mark it on the drawings.
Special attention should be made in the bathroom/WC and kitchen areas. Mark out on the floor the location of shower trays, bathtubs, WC and kitchen units, as no pipe work should be laid in these areas. After the pipe is installed in these rooms take photographs so all trades are in no doubt as to where they can and can't fix down.
Marking Out
Once satisfied with the design, mark out the rooms. Take a length of baton 2metres plus and - starting 100mm in - mark out the required spacing on the baton, as per the UFH design, this can then be used as a marking stick and moved around the room.
Always start on an inside wall and work towards the outside of a building. If there is any change in the room size it is better to have closer spacing on the outside wall than the internal walls, because of heat loss. Where the pipe enters and exits a room, mark with arrows the flow and return so you are clear which route the pipe should take.
A Question of Space
When fixing the manifold to the wall, allow plenty of room for the heating engineer to make the boiler connections to the mixer or injection unit on the manifold. This should be at least 50mm at each end of the manifold and mixer assembly. The Continental range of HeatMax™ mixer systems or injection units have been designed to give flexibility on site - these can be installed either right or left-handed, dependent on the position of the boiler pipework. The manifold assembly should be positioned 700mm off the finished floor level, as this will ease the connections from the UFH pipework onto the manifold.
The Perfect Fix
The manifold assembly must be firmly fixed to a wall. Sometimes these fixings can be awkward, particularly with stud partition walls, where the position of the stud may not coincide with the position of the manifold bracket. In these circumstances it is advisable to fix a 10mm sheet of ply to the wall to ensure a sturdy fixing.
Where a manifold and mixing or injection unit is being used it is easier to first fix the manifold to the wall and then connect the injection or mixer unit, followed by the ball valves and manifold end sets. At Continental all our systems are designed with flat seal connections to ease this process.
Pipe Points
- With a Continental designed system a cutting guide is always supplied, indicating the cut length of pipe for each UFH zone. This avoids errors and pipe shortages on site.
- Number the uncut coils before you start to lay the pipe, this will ensure you know what cuts have been made from each coil.
- Before laying, check the measurement mark on the roll of pipe and make a note of it.
- Fit the pipe starting at one end of the manifold and work methodically through, laying the pipe to each following zones until the other end of the manifold is reached. This allows easier access to fit the pipe to the manifold and makes it simpler to follow the design and ensure accurate pipe layout.
- Continental supplies a variety of different pipes. However, from experience the multilayered pipe, typically Pex/Al/Pex, has been found to be the easiest to install because it retains its shape when bent.
- When creating a bend in the multilayered pipe, roughly form the bend and then firmly hold the pipe as if holding the steering wheel of a car and slowly move your hands backwards and forwards until the desired radius is formed.
If the centre of the pipe is less than 200mm then forming a neat bend can be quite tricky, especially if the spacing is 100mm. To overcome this simply use a 16mm external pipe bending spring and feed this from the start of the pipe to the return at the manifold. - After connecting the return pipe to the manifold, check the measurement mark on the roll of pipe and subtract from the previous measurement to ascertain the length of pipe used. Make a note on the CAD plan of the length of pipe used so the flow rates can be checked against the original design.
- The UFH pipe must be protected against movement in the screed where it comes up through the screed to join the manifold - use conduit sleeving to do this. The pipe also needs protection where it goes through walls and at expansion joints in the screed. Building standards state there should be an expansion joint in every 40m2 of screed or in corridors every 8 metres. The pipe should again be sleeved at this point 300mm to each side of the joint.
- After pipe laying has been completed make sure it is adequately clipped and secured.
- If a liquid screed is being used, extra staples should be used, Continental recommend 3 staples per metre. The reason for this is liquid screed can flow under the pipe work causing it to float to the top. A box of pipe staples is much cheaper then having to dig up screed and replace pipe work.
Team Work
Continental are available on 0845 108 7001 to offer technical support for their customers.
Ultimate Solution
Continental Underfloor Heating also provides a nationwide underfloor heating installation service. The Continental in-house team of installers can project manage an installation from start to finish, liaising with on-site contractors to schedule an installation date that best suits the project build.
Log onto www.continental-ufh.com or call 0845 108 7001 for more details.
