(Ground worker from drilling company)

After my colleagues left the site with the drilling rig to go to their next customer, my part of the installation started. My responsibility is the hydraulic connection of both ground loops to a manifold.

From the site plan, I knew the position where the manifold pit was to be installed. The pit itself is built up from a pre-formed plastic frame. Each segment of the frame has to be connected together but this approach gives the flexibility to customise the pit to the site requirements. The pit is large enough to work in, with a manhole cover on the surface for access.

Each borehole contains four pipes for the ground loop collector. My company prefer to use a double U-tube collector to optimize the energy gained from the ground benefiting the customer with long term, stable performance.

With two boreholes, I have to connect a total of eight pipes to the manifold, four to the collector and four to the distributor. For long term reliability the connectors are thermally welded. During this process I have to take care that no dirt or other debris blocks the ground loop pipework or the manifold.

All connections were pressure tested after the installation was finished to check for leaks. Searching for leaks after the whole installation is finished would be too difficult and may require additional digging, so it is essential that each stage of the pipework is tested before any ground is re-instated.

Before re-instating the soil around the boreholes and the trenches containing the pipe connections, the ground loop is covered with a 10 centimetre deep sand fill to protect the pipework from any possible damage by sharp stones.

What we learnt: After each installation step the ground loop collector should be subjected to a full pressure test. To record the testing procedure and provide evidence of a completed job a test certificate should be provided to the customer.