Finally got to the bottom of the very anoying red light on my sunnyboy 1200, indicating a ground fault. By working back, i first found it was only one of the turbines, then not the cable, then not the circuit board, and finally found it was the heater element that was causing the issue, as when disconnected (with turbine off) the error disappeared. On closer inspection the resin type stuff on it seemed very saturated and was very sticky. I took it out and ramped 3 car batteries in series through it in a small beaker of water. It didn’t get very hot, so i added boiling water to it, in the hope it would clear any water lodged in it. It seems to have worked nicely, as now the error has gone, and i am quite delighted to be back to reading almost as before. About 1020W total, the slight loss (of 20W) i reckon is due to the increase length of pipe i have used in pumphouse to avoid tight bend angles, though i may be able to optimise it further by bleeding more air out after leaving them sitting overnight. Will see.