S
shaun.
Hi new to this forum any help available would be appreciated, have got a domicondense ferroli f28 combi boiler that has been throwing a f05 and a15 fault which shuts the boiler down,have got a service plan which they replaced an air pressure switch and was told primary exchanger slightly scaled as making a noise now and again when dhw used, so i put sentinel x400 in and used for 3 weeks and flushed the radiators out, refilled and used heating for a further week and flushed out again water dirty but nothing major,my heating works ok my dhw works ok, my problem is central heating water is set to 75 on the boiler and dhw set to 50 when using hot water or central heating boiler is not modulating the temp it just keeps rising until over heating thermostat intervenes shuts the burner off until cooled and then starts back up again is there a simple reason for why this is happening, thanks.
