Having a real nightmare with a heat pump. Have installed with 63a MCB on non-RCD side of consumer unit, with properly sized cable running to local isolator above heat pump. Heat pump only requires high ampage during startup (it has a scroll compressor) - normal running is around 20 amps. It contains an backup electrical cassette (3kW) to heat water which is randomly tripping the 63a MCB after between 2-10 mins of operation, and for love nor money I can't understand why!
I'm on the verge of getting a sparky in to have a fiddle (I'm a heating engineer) - just wondered if anyone has an idea what might be causing this?