Best to get him out asap, given S*d's Law will cause the unit to pack up over Christmas. Hopefully it'll be something that can be easily / quickly repaired replaced on a like-for-like basis.

Pumps these days - at least in the better boiler makes, should be more than capable of lasting the average lifetime of the boiler, which for small footprint ones like combis / wall-mounted system boilers is around 15 years.

Worcester-Bosch boilers are decent quality (top three with Vaillant and Viessmann last time I checked), so the pump should be. I presume that your unit is not under warranty? You may have been unlucky on that score as increasingly the top brands now offer minimum 5 year warranties, and 7 & 10 year ones if fitted by one of their 'expert' fitters, which essentially is just a plumber who's done an extra course or two to justify a higher fitting charge.

My Vaillant, fitted in 2019, came with a 10 year warranty - which covers everything (parts and labour - manufacturer repair - not my plumber) aside from the wall controller (only 1 year I think) and heat exchangers (2 years). Quite handy as the unit ages. I must admit than mine wasn't as reliable as I'd hoped - 3 callouts (FOC) in the first 3 years, though none this year.

I might go for a Worcester-Bosch next time, or Viessmann if there was a decent plumber who knows them (parts and local plumbers who know the units more difficult to come by than other makes).

Checked warranty here: www.worcester-bosch.co.uk/guarantee-check

Covered until Aug 2029 :)

Although the list of what's not covered is longer than the list of what's covered. Not unreasonably it doesn't cover failures caused by:

• Failure to install to manufactures [their typo] instructions or relevant standards
• Contaminated system water
• Contaminated or insufficient fuel
• Non Bosch controls or ancillary products
• System (non boiler) related issues
• Lack of annual maintenance
• Incorrectly specified equipment

So would have to be a bit careful to find all the service records before calling them out.

Boiler man here now, and the answer is... condensate pump, as suggested by Heidfirst. Man says 4 or 5 times a day is fine.

He's going to look into the 276 flow sensor fault.

4-5x a day - fine, for a more powerful boiler configured to run in condensing mode a lot. More than that, no, in my view. The float sensors can fail, sometimes by the reservoir getting clogged up with gunk, though far more of a problem on A/C systems with them, as it's ordinary water rather than slightly acidic.

Might be worth your plumber checking the reservoir and pump impeller and cleaning as necessary at the next service if the unit has become noisier and running more often than originally.

Local plumber gave me advise to which boiler to go for he says u want bosch worcester its a audi you want valliant its a Mercedes u want baxi a toyota

Not sure about that analogy. In my experience, Baxi were always a middle-of-the-road outfit, product quality-wise. They may have improved - do you have any reports (e.g. from Which? magazine, etc) to validate your plumber's claim? I also did here that Ideal had made some decent improvements. Many will often big up what they (mainly) are most familiar with in order to get more business.

In my view, Vaillant and Worcester Bosch were top of the tree for gas domestic boilers for a long while, with Vaillant being easier to use but not as good on the reliability front, plus more plumbers appear to be familiar with Worcester Bosch ones.

I think that in more recent times, Vaillant have regressed to some degree, though perhaps it depends upon which boiler you buy.

I think that Vaillant have been overtaken on the reliability front by Viessmann, though sourcing a plumber who is familiar with them ( install and maintain) locally is much more difficult than the other two, as their boilers aren't sold in that many numbers in the UK.

Many makes offer 7 and 10 year warranties, depending upon who installs the boiler. Whether a system should be power-flushed depends really on how old it is, the type and condition of the pipes, connections and radiators, as on older systems, doing so can easily open up holes or break open pipe connections previously held together by the build up of crud in the system over decades.

More so on systems with metal pipes than plastic ones (less joints and likely a newer system).

I had an IDEAl fitted during lockdown (there wasn't anything else available). It's supposed to have a ten year warranty, subject to servicing conditions, I guess like modern car main dealer stipulations. OK so far, but I'm getting servicing through IDEAL.