Heat Pump Barrel Union plumbing connection for Astralpool iHP heat pumps, Madimack, Sensaheat and many others. These are unusual, as 50mm PVC pipe is glued over the socket fitting. Please note last picture of thread style.
- Nut Thread Internal Diameter: ~ 71.8mm
- Nut-side Tail Outside Diameter: ~ 74.8mm <--the part you'll see on your heat pump.
- Socket OD: ~ 60.5mm (glue 50mm PVC over this)
As always, PVC pressure pipe dimensions are different to what they are named. See here for explanations.