On Thursday, 9 April 2020 08:29:24 UTC+1, RJH wrote:
On 25 Mar 2020 at 16:23:05 GMT, ""Dave Plowman" News)"
wrote:

In article ,
David wrote:
It's difficult to buy a truly bad new car these days, just as it's
difficult to buy a truly bad boiler. Pretty much all cars and pretty
much all boilers are fine.

Be interesting to know the average lifespan and number of breakdowns etc.
Saving a few quid on purchase costs may be poor value if it need lots of
repairs and early replacement.

That's the sort of data Which should be able to get from its members.

They do a general survey - 9000 households, 200 engineers. Top 5 Worcester,
Vaillant, Viessmann, Potterton and Ideal. Bottom 3 - Headline, Ferroli and
Biasi (same for engineers and households).

Depends on the data and criteria they use - sometimes service call outs are taken into account, rather than just the quality of the appliance. The best quality boilers on the market, that all those in the heating industry (not plumbers) would agree on a Intergas, ATAG (both Dutch who invented the condensing boiler) and Navien. Navien are Koran who are the biggest boiler manufacturers in the world - been available in the UK for about 5-7 years. Viessmann are below them, who have recently dropped in quality. The rest lag way behind the top three with Worcester Bosch, Ideal, Baxi and Vaillant way overpriced for what they are.

Navien have advanced designs with even touch control user panels with also great touches like taking the outside temperature for weather compensation from satellites, so no wire to a sensor on the north side of a building. Their stainless double pass heat exchangers do not need cleaning. The latest Intergas and Navien boilers modulate way down low, to under 3kw. When on an Opentherm thermostat (really a sensor not an on-off stat), the burner modulates to the demands of the building. Only when the demand is below 3kW, or lower, will any burner cycling occur; by then the building will be up temperature anyhow with heating off.