pump currently setup to draw water downstairs then through the backboiler and around the system - which goes back upstairs! so how do you determine the correct flow except for the location of the LS valves with relation to the flow of water through them?
i think single pipe - house age circa 1950s - but the pipe work connecting the rads is grey plastic 15mm, so i think the whole system was revamped when the immersion boiler was installed approx 8 yrs ago, but the pipework from the backboiler seems all original - copper larger bore. immersion...
also - woithout intentionally sounding like a fool - whats the cold feed? - the header tank? - if so would a rotten bit of carpet that had been used to cover the tank which had subsequently fallen into the tank potentially cause problems?!
sorry - 'both pump valves'? - the pump is a DAB - identical to the grunfos(?) that came out - the plumbers were out of the yellow pages - one of whom is apparently a reputable chap (the one that recommended the new system!)
all rads were working fine - except the one in the downstairs extension (ie. rad added later) - lockshield was completely shut. when i opened the valve i could hear water filling the rad - seemed to be totally empty. since then all but two rads have stopped working completely. i've drained the...