DIY Doctor UK DIY Forums

Hi, I have an Ariston EuroCombi that does not modulate up in hot water mode. I have replaced the diaphram in the diverter valve, the diverter activates the micro switches and the boiler switches on in response to a call for hot water, but the burners remailn low. Could it be a fault with the temp control stat, gas modulator or pcb - any ideas or process of elimination would be appreciated!

First thing to check (been caught out with this once), check the gas meter ECV is fully open - it may have been knocked and may be partially closed.

The burner pressure may need resetting, or may be fault with the gas valve (either way you need a RGI).


htg