Experiences with brine heat pump

have a Novelan, runs at 50 degrees and the disinfection program runs once a month. According to the manufacturer, it is only necessary every 3 months

I have it completely off because I have chosen the water storage size so that the water changes as often with showering and consumption that nothing can multiply on a large scale. I think the frequency of disinfection should also be based on how large the storage is compared to the consumption.

It is not the amount of water running through the boiler that matters but the temperature. Legionella bacteria only die at 68 degrees because proteins coagulate at that temperature.

You are on the wrong path. Legionella need time to multiply; you always get a few through the regular tap water into the storage tank. If the water exchange rate is high enough, the concentration of Legionella remains at a harmless level. Only if the storage tank is too large does the concentration become too high, because the multiplication then proceeds faster than the water is replaced.

hmm... then I apparently failed in my studies and have been doing everything wrong in my profession for 25 years...

With your method, you might keep the legionella at a constant concentration of about 75%, but you have a very high risk that they could break out. You can minimize the risk 100% if you kill the entire strain, which you can only do from 68 degrees.

A rather unfair argument to equate a personal mistake with complete failure in studies and career, that is not a factual discussion. I do not find any real arguments or factual information about Legionella in single-family homes in your post apart from the arbitrary percentages (where do your 75 and 100 percent come from?).

By the way, it is not my method, but common practice and without "maybe." You continuously get new Legionella through tap water. You can only keep them away permanently if you keep the water temperature above 68°C, which is uneconomical with heat pumps (and the storage losses are high). Otherwise, there is no 100% prevention. Heating at regular intervals is also nothing more than a minimization because you never kill 100% (just google the studies), and at the first draw, you get new ones through fresh water. The deciding factor is thus the concentration. If the water exchange rate is high enough, that is completely sufficient. If the entire water is exchanged every 2 days, what should a weekly heating bring? You heat water with a Legionella concentration that is basically at tap water level and shortly afterward it is exchanged anyway. Incidentally, when heating the storage tank, long-unused pipes etc. are not heated, so circulation lines and rarely used showers (you get infected particularly quickly here through the water droplets in the air) are actually the major risk of infection!

The comparison with hospitals is also wrong, this is about single-family homes and the infrastructure, pipe lengths, etc., as well as the requirements in hospitals (where there are weakened persons), are probably quite different.