Sjb338

Hi there, I have aquired a Chinese unbranded hot tub that is approx 8 years old. It had been standing drained and unused, for approx 6 months before we got it but was assured it worked before being drained. After making all the electrical connections it was tripping the RCD. I have disconnected all the pumps and heater from the relay board and the control panel now powers up fine. I have however tested the relays with a multimeter and it appears that they are stuck on closed (powered). I have concerns that the pumps ( Whirlpool LP200) are also faulty as they appear to have continuity on the cables feeding them between Phase and neutral - I assume this is incorrect however all pumps as well as the heater test like this??? Note - the cable that feeds the heater appears that it may have got hot in the past inside the control box as it had become brittle. This shad now been cut back ready for reterminating. Do I need new pumps / heater all round or am I missing something?? Thanks Sam