Ground Source Heating – Pipework Part 1

This is an update regarding installing the underground sourced heating which should provide 4KW of heating and hot water energy for 1KW of electricity. The heat is delivered via wet underfloor heating. This type of system delivers a relatively low temperature heat and takes quite some time to heat a room unlike a conventional central heating system. It is most commonly left on permanently. As with any heating system the more insulation you have the less heat you need to sustain the temperature. Part of the installation as you may have seen in the previous posts – the Rip Out and Concrete Day – was to make room for the insulation and pipework. There is 100mm of insulation and the pipes will eventually sit in 70mm of screed on top of the insulation.

Heres a breakdown of the different layers:


The next couple of images show the insulation being measured, cut and installed on the floor.



As you can see the insulation panels are also taped together with a silver tape – this is to prevent the screed that will be added, going down the cracks and bridging the insulation.

In the image below you can also see along the edges of the insulation at the walls some expanding foam is also used to fill in gaps to insulate and again prevent screed from dropping into the cracks. The yellow marking in this picture is where the stairs will attach to the floor. There is no point heating in this area and also we need to ensure that fixings for the stairs do not puncture any of the pipes – which you can see sitting in the clips.


This has been a challenge – making sure that the installers know where to place the pipes and what areas to avoid. A good set of plans is necessary and I ended up drawing these on my electronics cad package not only for this part of the job but also in preparation for the electrician and plumber and to plan out the rooms. Doing this allowed me to make decisions such as making the small bedroom a bit smaller allowing us to fit a double bed in the middle size room. The ground source heating guys are much more used to working with new builds that have architects drawings. They came to site but missed obvious things such as the joist spacing’s not being consistent or standard and although they did measurements they still want you to supply accurate drawings later on.

Here is an example of the drawings I ended up supplying:


Even then in a property this age – nothings quite straight , parallel or level. Walls are different thicknesses etc so translating the plan to actual positions in real life is potentially not that accurate and remember when the screed goes down we wont be able to see the pipes so – be careful where you put any fixings for stud walls etc.

This is the type of plan we were given for the pipe installation :


As you can see each room has its own zone if not two so the temperature control can be optimised. There are individual room thermostats connected by wireless to the manifold.The flow rate around each loop is then controlled by individual valves on the manifold.

We will be upgrading the insulation on all the walls as we have thin sheets of polystyrene which is one of the poorest insulators and the plasterboard is damaged in a lot of places – as all the internal walls have to be built and plastered it also means we will have a consistent and quality finish at the end.

In this image you can see two upstanding pipes which will be for a towel radiator in the downstairs bathroom.


Here you can see the manifold and all the pipes leading back. As these pipes get close together the return pipes may have given up some of their heat so there is some insulation – black plastic tubing in this area to stop heat transferring from the incoming hot pipes to the cooler returning pipes.


Next week we have the pipes for upstairs going in which is installed differently so I will cover that in part 2. Hope you find this interesting – any questions please ask.

Remaining images of install :




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