thats just it i dont? had a plumber round he said to flush system by putting sentinal x400 in to f&e tank while drained down so it was in system then refill and run it up for a while, this didnt seem to work, had a central heating guy in yesterday he then told me to put half a ltr x800 in one of...
can anyone help, I have hot rads upstairs, cold downstairs! I have flushed and bled system, still the same, turned upstairs rads off then down started to get warm - hot, when rads turned back on upstairs (even one) downstairs go cold