I have an Ideal WLX RS50 Boiler.I recently fitted a new 2 port zone valve and pump in the c/h .All operating ok.But when selecting h/w the zone valve for h/w operates ok the boiler fires up and the pump comes on. Problem is the hot water from the boiler is not circulating to indirectly heat the water in cylinder. ANY SOLUTIONS WELCOME.

JOHN CAMPBELL, September 2009

probably air locked of some sort. assuming you exchanged components that were there in the first place and not adding bits for fun?! bleed anything u can and run the heating/water with the pump on minimum speed until it sounds quiet then build to speed2-3.

gilo bg, September 2009

doesn't sound like it's a gravity hot water system.
if it is it shouldn't have a zone valve and the pump shouldn't operate when on hot water only.
for gravity h/w & pumped ch you would generally have 28mm flow and return pipes (may be 22mm) going to the cylinder then the pump on the c/h flow.
you generally wouldn't need a zone valve for c/h as the pump act's as the control for the heating.
the boiler would fire immediately for h/w when you turn on the timer as that's the only control you have over the water, when c/h was turned on the boiler and pump should fire.

Hope this helps.

Ian, September 2009