This problem seems to occur randomly throughout the year but recently this has been happening more often. On several occasions this winter the boiler does not spark up when the hot water tap, in either the kitchen or the bathroom, is turned on - to get around this I have to turn the central heating on constant. In addition, since the central heating has been turned on the hot water coming through the power shower is luke warm.

Rach, March 2010

had same problem hot water just goes cold found it was temp senser working intermitent cost about 37 pound 20 mins to fit

dean, February 2011

I have since turned the heating off and it has been great, have hot water through the taps and the shower has been hot. However, just in the last week the boiler has not been sparking up and so the heating has to be put on to get any hot water. Also finding that if the boiler does work and you do get hot water, either through the taps or the shower, it can go cold at any moment but on the other side the water goes extremely scolding hot. Is this still something to do with the diaphragm.

Rach, June 2010

We have experienced the same problem on and off for around 18 months. We have just had a new circuit board fitted at a cost of £300!! The water is still running tepid and then freezing cold - no baths in our house!! The plumber is coming back this week again but seems baffled by recurring problem.

Diane March 2010, March 2010

On top of the diverter valve is a small microswitch,these often fail, they become erratic bofore they go completely.The gas engineer should have changed it before swapping diverter which costs £80 .Get a new switch from maplin
for 90pence!

Rob, March 2010

I have exactly same problem, but had the diaphragm changed in valve worked for a day and now not working again, been told it may also be the thermostat. Its driving me mad I put the heating on jump in shower then the hot water just goes after few mins. Let me know what fixes yours sounds like we have same problem!!!

Jess, March 2010

sounds like a dodgy diaphragm not operating the microswitch for the domestic hot water, most boilers quick simple fix but alpha are sh1t!!

rawplumb, March 2010