On Thursday, April 9, 2020 at 2:48:02 PM UTC+1, John wrote:
On Thursday, 9 April 2020 12:47:23 UTC+1, Dave Plowman (News) wrote:
In article ,
John wrote:
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.

Interesting. I chose a Veissmann some 12 years ago, based on reports here
and elsewhere. Not regretted the choice. Was impressed with the build
quality on the one repair it's needed in this time. Things like the PCB
including fuses on all the outputs. Even although they're soldered in, and
not something the average repair man would fix.

Spares are pricey, but availability and delivery very good.

Only real complaint is the user interface. Setting up things like the
weather compensation. Which I'd hoped would be addressed on later models
by doing it all via your phone or PC, rather than fiddly multi function
buttons on the programmer. But I think par for the course at that time.

Shame if they've dropped back in the pecking order. I did a self install,
and the human on the other end of the help line couldn't have been more
helpful. He was obviously an engineer, rather than just a phone advisor,
who had to look everything up.

Viessmann have flagged recently. The quality of the older models you can testify to. Pricey spare parts is not an issue with reliable boilers, as you rarely use them. The best by design is Intergas. The quality is high as well. The bi-thermal heat exchanger is flat being as big the casing, located at the back of the casing with all components at the front, being easy to get at the few component in the thing. The intergas is a two man lift it is so well made. The boiler was introduced in 1996 in Holland in response to a call for a simple, reliable, low maintenance, combi for the Dutch social housing market.

They listened to the servicemen to what they wanted as they were starting uncompromised from a clean sheet, they were not designing a boiler to be an assembled "kit" of of third party parts as most are. The Intergas Rapid is still basically the same 1996 boiler, which was "way ahead" of others at the time with weather compensation and Opentherm as standard and not overpriced either; Opentherm protocol is used extensively in Holland. They first came into the UK rebadged by a small UK company called Atmos - who also rebadged other makes. Sales were by reputation, then Intergas established themselves in the UK as manufacturing and UK demand increased. They have introduced a number of new models since, however the same heat exchanger design is used.

I believe Vaillant wanted to buy out Intergas to get their hands on the heat exchanger. They did talk about making the heat exchanger under licence. The Americans/Japanese beat them to it buying the company, which will still operate independently in Holland. Vaillant are still buying French Gianoni heat exchangers. Whether the heat exchanger will also be made elsewhere to meet Intergas' demand is yet to be seen.

Others makers have chunky heat exchangers, either square or round, the round French Gianoni is common in Vaillants, Baxi and others. These types are not a good fit inside the casing, leaving wasted space around them. Subsequently, when manufacturers make combis (the biggest market) they have to squeeze in a plate heat exchanger, 3-way valve, pump and all the other pipework and sensors. This makes servicing difficult in that common fail components have to be removed to get at those behind - a big job to replace a small cheap component. Look at this on the Intergas design, the heat exchanger is all the back, what you need to get at is on the front. The whole front of the heat exchanger lifts off by removing 10 bolts to clean:
https://www.youtube.com/watch?v=0nHjm19Oi6I

The boiler for advanced electronics is Navien. They even coat the pcb with a plastic coating in case water gets on it.

I think it's the ATAG A325ECX combi that has integrated flue heat recovery in for DHW, which increases the DHW flowrate, and efficiency of course.

Am I the only long-standing member here who is reminded of our late(?)
lamented(??) International Man of Mystery, aka. Doctor Drivel?

(John is not necessarily expected to understand this)