main combi 30 eco diverter valve

[phil hair]

hi, i have a main combi 30 eco that has heating but no hot water.
I changed the diverter cartridge but that did not fix it. the hall sensor is on, the diverter motor is working, the preheat is working , and although the 'tap' led is lit up, the fan doesn't start, no ignition,ect.
should i have changed the whole diverter valve, or could it be the board?

thanks............

 

[AMGasServices]

There are two types of flow sensors on that boiler (earlier version and a modified version). In a lot of cases the magnet gets stuck. Before going for the PCB I’d looking at changing the flow sensor.

Also look at your dhw thermistor resistance reading too. If it’s saying the boiler is up to temperature the boiler ain’t going to fire try this before the flow sensor.

 

[phil hair]

thanks, the hall sensor is showing a light, the tap neon is on, so it is recognising a demand. The preheat is working to, so the diverter is working some of the time? need to check the thermistor, but why would the preheat work if this was faulty?