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BHE horizontal connection · Ø 32–63 mm
Our horizontal connection: pipes from probe foot to manifold — sized Ø 32–63 mm per system. Used in dozens of probe fields — from single-family homes to neighbourhood developments.
Invisible — but decisive.
The backbone of every system.
Between borehole and heat pump lies the connection pipe — frost-deep in the ground, pre-insulated where required, pressure-tested. The piece nobody sees, and without which nothing runs. Heating or cooling — the pipe handles both.
The journey of heat
Five stations.
One cycle.
Scroll along — from the depths into the living room. Five stages every geothermal project goes through.
Technical depth
Material, pressure, frost depth.
The connection pipe is the piece of the system you see the least — and plan most carefully. PE 100 RC, pre-insulated where required, pressure-tested to SIA 384/6.
Pipe material
PE 100 RC
Cross-linked · diffusion-tight · service life ≥ 50 years per SIA 384/6
Standard dimension
Ø 50 mm
From probe head to manifold · also Ø 32 / 40 / 63 mm possible
Pressure class
PN 16 / SDR 11
Standard · for deep probe fields PN 20 / SDR 9
Burial depth
1.2 m
Below the Swiss frost depth · regionally 0.8 – 1.2 m
Pre-insulation
PUR foam
20 – 30 mm insulation · minimises heat losses along the route
Pressure test
3 bar · 30 min
Per SIA 384/6 · before commissioning · documented
Heat-transfer fluid
Water or brine 20 – 30 %
Plain water or water-glycol mix · antifreeze down to −10 °C · corrosion protection
Manifold
Plastic (PE)
Hydraulic balancing · flushing valves · one circuit per probe
Wall penetration
Sealed, pressure-tight, frost-safe.
- Press seal — stainless-steel sleeve, watertight under pressure up to 0.5 bar (static water pressure up to 5 m above slab).
- Frost-safe — transition ground → wall insulates between 0 °C outside and ≥ 10 °C inside.
- Flow / return brought through separately — both pipes pre-insulated where required, pressure-tested at 3 bar.
- Not to be underestimated — wrongly done: water ingress, thermal bridge, mould. We use only certified systems.
Heat loss
Pre-insulation saves measurably.
Without pre-insulation
≈ 8 W/m
for a 30 m pipe: ≈ 240 W loss · equals 2'100 kWh/year
With PUR pre-insulation
≈ 1.2 W/m
for a 30 m pipe: ≈ 36 W loss · ROI < 4 years
Assumption: brine flow 0 °C, ground temperature 10 °C. Pre-insulation 20–30 mm PUR foam. Values per SIA 384/6 and manufacturer datasheets.
Pressure test per SIA 384/6
Tight in three steps.
- 01Pre-test with water at 3 bar · 30 min · visual inspection of all joints.
- 02Main test pressure-hold test 30 min — permissible drop max 0.1 bar.
- 03Protocol & handover with test pressure, temperature, duration, visual findings — part of the handover documentation.
Heat-transfer fluid
Brine — the invisible hero.
Base medium
Water or water-glycol
20 – 30 % propylene glycol · biodegradable · non-toxic
Antifreeze
to −10 °C
At 20 – 30 % concentration · sufficient for Swiss conditions
Corrosion protection
Additives
Steel and non-ferrous metal inhibitors · pH-stabilised
Maintenance
every 5 years
Concentration and pH check · top-up if needed
Route planning
Minimum clearances underground.
| Third-party system | Minimum clearance | Source |
|---|---|---|
| Electrical cables | ≥ 0.5 m | SVGW · NIN |
| Water pipes (drinking water) | ≥ 0.4 m | SVGW W1 |
| Gas pipes | ≥ 0.4 m horizontal · ≥ 0.2 m vertical | SVGW G1 |
| Trees (trunk axis) | ≥ 1.0 m | SIA 318 |
| House wall / foundation | ≥ 0.5 m | Best practice |
| Sewerage | ≥ 0.4 m | SVGW W3 |
| Min. bend radius Ø 50 mm | ≥ 500 mm | Manufacturer datasheet |
At crossings with other media, protective sleeves or separator plates are used. With different geology (e.g. rock band) the bend radius can be adapted.
Manifold
The heart of the hydraulics.
- Material · PE — corrosion-resistant, condensation-safe
- Layout · one strand per probe, parallel distribution
- Flushing valves · for commissioning and individual circuit cleaning
- Air bleeder · manual at the highest point · optional
- Pressure gauge · pressure check on all flows and returns · optional
- Shut-off valves · each circuit can be isolated individually (maintenance, repair)
- Hydraulic balancing · Inline-Setter or strand regulator on each circuit
- Heat meter · optional for monitoring system performance
≤ 0.2 KTemperature difference between circuits after balancing
10 – 20 %higher efficiency through correct hydraulic balancing
≥ 50 yearsplastic manifold service life · low maintenance
Practical example
Horizontal connection Ø 32–63 mm.
Gallery
From the field.
Probe to manifold.
Manifolds, pipe runs, pressure tests - a selection of completed connections.
Our promise
All from one source.
Probes, pipe, penetration, connection — in one project, with one contact. No interface ping-pong between trades.