Thank you!
checked but could not find the drain still; I think because I have a different type:
https://www.hayward-pool.com.au/assets/documents/poolsaustralia/pdf/manuals/energyline-pro-inverter-series-heat-pump-manual.pdf it's the ELPI - 17 I have.
The manual refers to a drain:
5.2 Winterising » Put the heat pump in “OFF” mode. » Turn off the power supply to the heat pump. » Empty the condenser with the help of the drain to avoid any risk of deterioration (high risk of freezing then cracking). » Close the by-pass valve and unscrew the entry/exit connection unions. » Eliminate the maximum amount of residual stagnant water from the condenser with the help of an air gun. » Close the water entry and exit areas of the heating pump to avoid introducing foreign bodies. » Cover the heating pump with a dedicated winterising cover.
I will have another look to see if I can spot it 🙂
Many thanks!