I have been on their course and fixed one.
Its odd that you can hear these negative views but never actually get told of what common faults they can show.
But I would seriously prefer the Viessmann to the similar Ideal Istor. [ although Ideal thoughtfully added an electric immersion heater perhaps knowing the boiler might spend more time faulted than working. ]
But I went to one Istor and the nupty installer had never connected up the immersion element.
Its odd that you can hear these negative views but never actually get told of what common faults they can show.
But I would seriously prefer the Viessmann to the similar Ideal Istor. [ although Ideal thoughtfully added an electric immersion heater perhaps knowing the boiler might spend more time faulted than working. ]
But I went to one Istor and the nupty installer had never connected up the immersion element.