I have a Potterton Netaheat electronic boiler, the CH heating works OK (pump is working for CH) but there is no hot water coming from the HW tank (ie I have waited to heat up over several days). I think HW is gravitiy fed. When HW switch is on, the Pipes that take water to/from the boiler at the immersion tank both remain cold and also when slightly un done no water came out of the top one and only a little from the bottom one. Header has water and is filling up OK. Any ideas? It seems like there is not enough water circulating to heat the water.

Will, December 2007

Thanks both for your help. It didn't work on summer setting. will bear in mind that it could be diverter valve. However, It seems to have been fixed after a bit of fiddling! I put a long piece of flex down the top up pipe leading from the header and either it was an air lock, piece of limescale or something but after that water arriving at the immersion tank was hot and our water was getting hot. I also topped up the header tank which may have been a bit low, but certainly had plenty of water in there to my mind. I Like your idea jitparmar, hadn't thought of that and will try that if this happens again. Goodness knows how air got in or indeed limescale.
thanks for your help again.
Will

Will, January 2008

Hi, I have identical problem with Kingfisher II. I remove the thermostat stick in the boiler, turn the thermostat switch to maximum, and switch off central heating room thermostat. Let the boiler overheat, it makes hell of a noise, the upper pipe of the coil in the tank heats up first. The thermostat stick is replaced and all well until a few days later same problem and the cycle repeats. Remember when the noise starts the overflow tank will overflow and spill hot water so make sure the overflow pipe is properly connected otherwise your loaft will get wet. I feel this is due to air lock. But where does the air get in to?

jitparmar, December 2007

Will,

Sounds like your diverter valve may have stoped working - have you tried putting it into summer setting - with Hot water only ?

I am assuming its not a combi - boiler.

Divereter valves should be available from plumbers merchent and should be easy enough to replace if you have an adjustable spanner - worth draining down a bit first so you don't get too wet

Cheers

Martin, December 2007