[rusk]

You are bounded by a minimum floor for the hot water. Below a certain point you can get legionnaires.

To me it seems like one of two things: external pressure between hot and cold is mismatched so a small change to one side overwhelms the weaker flow.

Alternatively it might just be a broken or poor quality mixer that isn’t providing the appropriate ‘nuance’ of control, and that may indeed be expressed as some sort of non-linear relationship.

[GuB-42]

> Below a certain point you can get legionnaires.

I know you mean legionnaires' disease, but the idea of a bunch of soldiers getting to your house because you turned your boiler too low made me chuckle. Good thing the US have the third amendment to protect against this.

[detourdog]

In this day and age I believe anything is possible.

[BlueTemplar]

"What have the Romans ever done for us ?

... hot water baths ..."

[detourdog]

The thermostat could still be set too high. I think you might be overstating the dangers of legionnaires.

It also a simple thing to check and would be the first step in my troubleshooting routine for this complaint.

Here is a link describing the dangers.

https://www.heatgeek.com/hot-water-temperature-scalding-and-...