help stressed with boiler i have heating but no hot water i have changed both diaphrams and new pump and cleaned out both heat exchangers. boiler makes bang and clicking noise when turning hot water on and fontpin does not come out fully and boiler heats up and cuts off. before cleaning heat exchangers boiler CH has started working but still no hotwater can u help pls. thanks

chopper, December 2010

It sounds to me like the diverter valve still isn't working properly. I'm not sure what you mean by the fontpin, but if you mean the pin that moves out when the diverter valve operates for hot water demand, then this is most likely the problem.

If you have already changed the diaphram, dismantle the valve again and clean any deposits from stuffing box through which the spindle passes and make sure it can move freely. There is also something called the venturi which generates the pressure drop which causes the diaphram to move. Make sure this isn't blocked.

I'm not sure what the second diaphram you refer to is.

Mark, December 2010