Video :
Once a year, I clean the filter that protects my heat pump from dirt.
Many of my radiators and pipes in the house are 50-year old. When I replaced something, the pipes has often been half filled with dirt rust and lime. A heat pump costs $ 5000 here, so as to avoid any of this old dirt would tear itself loose and block the heat pump and maybe it could be damaged, I have used $ 50 on this filter device.