• Jeff Culkin

Boiler Service Repairs Paradox

It is prevetative maintenance to get your boiler Serviced? Does it stop repairs?

How long should the boiler work after a service? Can, why would the boiler break down after a service?


After many years of observation, running a company that carrys out hundreds of boiler services a year. Combined with a basic understanding of maths. I thought I'd set out my understanding on how a boiler service affects boiler reliability, with a mind to all the averages and how that might appear to any given comsumer.


First lets note the bithday paradox wikipedia.org/wiki/Birthday_problem if over 23 people are in a room it's odds on two will have the same brthday. It will be human nature when those two discover this to think it remarkable, yet statistically it is unremarkable.

Therefore if all things were equal and boilers broke down or had an issue once a year and I were to carry out 23 boiler services, it would be odds on that one boiler will breakdown on the same day of service. 23 boilers service dates and 23 repair dates (23 × 22) / 2 = 253 pairs to consider, which is well over half the number of days in a year (182.5 or 183). If we extend that to matching breakdowns in a week, we can drop the figure to 8; (8 x 8) / 2 = 28 over half the weeks in a year. Therefore for every 8 boilers serviced 1 on average would have an issue in the same week, or in the week following the service.

This is of course all based on a breakdown of once a year, most boilers will break down less often, at some age of boiler once a year or greater will be tip over.


The service will have the affect of reducing the likelihood of breakdown in the whole year, but the service may increase the likelihod of a breakdown in the near time after the service, as poor and damged components may be disturbed. I'll cover this in more dept later.

So if your boiler does breakdown the day after a service. Do not stop getting it serviced. As a human your brain will make the correlation and it will be very hard to dismiss "everthing was fine until". The truth more likely is that everything was not fine but there was ignorance.


How do we know the boiler was not damaged by mal practice. This is possible, but any reputable Gas Safe company is not going to have enginners who are going to be damaging boilers, modern apprenticships take years and servicing is a routine practice. Entry to Gas Safe registration is through. Rouge operative do existing and good operatives can make an oversite, however should that be the case an immediate issue should manifest after the service.



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