Worcester 350 combi when heating is on its it heats up but every 5 mins shuts down as if temp is reached but room stat is still asking for heat.
While the heating is on and you demand hot water it runs fine ,on stopping the demand for hot water the heating comes back on but no flame just pump and fan ,after this the hot water and heating will not work ,until I switch main power off and on even when I do this it for not always work.
Have replaced all temp sensors and thermostats and all switches check ok