As we have two ground source loops in 32mm pipe coming into the house, they will have to be joined up, or “manifolded” as a plumber would say into 38mm pipe. Here is the neat manifold that comes in the kit from the heat pump suppliers with shut off taps. There is one manifold for the incoming “warm” water/glycol mix at about 12 degrees C and one for the returning cold water which will typically be around -5 degrees C.

 So now the scaffold is down we have unfettered access to the outside of the house and can bring the ground source heat pump loops inside. The 32mm groud loop pipe has to be sleeved with closed cell foam for the last few metres as it approaches the house because it will be running at well below zero on the return side and could freeze the ground or any water pipes near it. Each 2 metre length of “Armaflex” is glued to the next with contact adhesive applied with a brush. You must use Armaflex because other plumbing products are not closed cell and will allow water into their structure which will freeze. Armaflex is available as a tube or a tube with a slit down the side. It is better to use the version without the slit and slide it on before you pass the pipes into the house if you can organise this.

We also  decided to give some mechanical protection to the Armaflex by sliding 85mm land drain pipe over it. Not the easiest of jobs due to the natural curve in the pipe and in the end we cut the 3 metres of pipe we needed into three bits to slide each one over.

Just three days later the second ground loop is buried and just awaits the scaffold to be removed so that we can take the pipes the last few metres into the house and hook them up to the heat pump.

How to stick 300 metres of ground source ground loop in the ground! Dig a trench 1 metre wide, 1 metre deep and 150 metres long. Put pipe in trench, order in 30 tons of soft sand, bed the pipe in this and then back fill the dig and top soil you took out.

We had got a bit ahead of ourselves and put the ground sourced heat pump ground loop in over a year ahead of starting the house build (the black pipes coiling out of the ground). With the recalculated heating requirement since then for possible future expansion we needed to add a second loop for the now larger pump. So we need to get the loop into the house and the pump connected once the underfloor heating is in place to start drying the house out. But with the scaffold in the way we cannot use a digger to make the final bit of trench to the house. And we can’t put the second loop in until the ground dries out unless we want to make a real mess of the adjacent field. Duh!