I got this husdata datalogger for my heat-pump.
It plugs in to a 3.5mm audio-connector inside the electronics box of the pump. On an IVT geo 312C pump it's fairly easy to install by removing the big front cover, then a smaller black cover, and then opening the electronics-box. I routed the wire into the pump via a tube-hole at the top, and then through the cable-hole of the electronics box (lower right). It plugs into a 3-wire 'BBT' interface.
The datalogger reads info from the pump and broadcasts it over wifi either to the husdata-website or over MQTT to any compatible device.
Datalogger with interface cable. 
IVT geo 312C electronics box, with husdata-cable connected to BBT-interface 
Pump information as displayed on husdata website.
