Hi d.o.n.
The best combi 600 28c costs me 950 with the vat and flue. A dedicated modulating radio programmable room thermostat is 70 plus vat. This particular combination is the best, the boiler burner is modulated directly according to room temperature, consequently the boiler quietly puffs away at low flame most of the time. A boiler which does this will last longer than one which comes on at full steam and goes out ad nauseum, and a boiler which modulates from room temperature wil condense more, and is quieter. The life of a boiler is closely related to the number of on off cycles. Also say you have a set temp of 20c and it is much colder, the boiler will initially come on hard but as temperature approaches 20 will modulate down in anticipation.This is partnered with an automatic variable head pump.Comfort, quietness and economy ensue. Because the receiving unit receives it's power from the boiler and the sender is battery powered no Part P qualification required (even though I have one) so cheaper to install.
If you do get a fitter to install a 600-28 c warn him not to use the template, every one I've had has the wrong distance for the flue from the mounting brackit it's one inch out. Fist time I found out once I was up the step ladder boiler in hand, I told them but they don't seem to have changed the templates, so just get your fitter to double check with measurements. The wiring for the radio stat is simple when you know how, there are only two wires but get your fitter to give me a call (http://www.pbarkerofscarborough.co.uk/index.htm) and I'll make it plane sailing for him. The thing is it's designed for the 500 range so the insrtuctions aren't explicit how to use it on the 600 range, it is the eassiest thing in the world once you know, but until you know it will trip you up.
The 50028c also works off the same stat boiler is about 100 less, doesn't have the variable head pump, slightly different hot water modus operandi but same overall performance, doesn't have as m,uch sound proofing and has a plastic cover. The 500 24c is another 40 less I think, I never offer anyone a 24 kw combi these days. To be honest I don't like copmbi's anyway and only fit them because people want them despite my advice so I couldn't bring myself to fit them a 24kw version, I don't even know whay they are offered, there is no reason in this day and age not to start at 28kw for the price of a 24kw.
The story is Nefit in Holland have been making these very reliable condensing boilers over 20 years, they have already the largest market share in Europe. When they saw that UK was coming into line with condensing boilers they wanted to get into the UK market which is the largest boiler market in Europe (see what size that will make them as a company). In their infinate wisdom realising Nefit doesn't roll off the English tongue they came up with the name Buderus, and to get a foothold in the UK market bought Boulter (or vice versa maybe a company man if reading this could correct me if I'm wrong about the direction of the takeover) who already market an excellent oil boiler in the UK.
A parallel bit of history is that Bosch were shopping for a boiler and wanted to buy Buderus but couldn't for some reason so they bought Worcester. However as soon as Buderus got established in the UK they said that's what we wanted all along, so bought it anyway and run it alongside sister company Worcester through a leg of their organisation called BBT. Some (not enough yet) of the Worcester engineers are trained in Buderus, when they come out they have Worcester on one side of their jersey Buderus on the other.
Why I like the boiler.,
Exemplary performance, thoughtful design (thinking of the service repair guy). Easy access to all components, easy change easy service). Read, can be kept going probably forever.
The part which writes off most boilers eventually is the heat exchanger. On these boilers undo four snap over clips and the outer housing splits in two, take out two retaining slides and pull off the specially treated (so it doesn't get clogged up with aluminium oxide) aluminium coil heat ex, about 5 minutes. New one is about 125. Same story for all parts.
There is much talk about heat exchangers at moment as manufactrurers find their feet in the condensing market. Buderus have done their r and d over 20 years with this same heat ex, they have a row of boilers back at base still going from inception with this heat ex. They also have a spray to coat the heat ex at the anual service which assists it in it's aluminium oxide rejection properties, but as it's branded Nefit they won't introduce it to the UK at the moment. I might see If I can get some from a dutch engineer.
If you aren't aware aluminium expands hundreds of times it's volume as it oxidises, small stones or grit are formed and in a badly designed heat exchanger the manufacturer doesn't make it easy for you to remove it, it clogs up the fins and your boiler will die of choaking and run very poorly until it's dead. The Buderus is the simplest heat ex to get at in the world is already designed to shed this oxide (into the condensate trap which must be cleaned anually) but even if not you can remove heat ex as described above, and even changing it alltogether is economical.
Make no mistake about it the future is grim for combi boiler longevity.
A big problem is that modern boilers can't cope with sludge, this is being blamed on the installer. Blame who you like sludge is a fact of heating systems, make your boilers better tolerate it. Hence avoid stainless steal heat exchangers which due to the poor transfer characteristics of thje material require maney more but much smaller passageways for suffcieint efficiency. There is already a bottle neck in a combi in the form of the plate dhw heat echanger, don't make it worse by adding a problematic main heat exchanger.
ht geng, if you r still with us. I take your point.
TA
