In an effort to minimize the usage of my 10-liter boiler and monitor hot water consumption, I plan to achieve this by monitoring the temperature of the pipe connected to the boiler. When the hot tap is opened, the temperature increases, enabling the activation of power based on this change. Additionally, I am aware that occasional activation of power is necessary to prevent legionella. Is there an esphome component available for this purpose?
I have an ESP8266 monitoring the cold water in and hot water out temperatures on my boiler using Dallas temperature sensors pressed against the pipes. As you can see below, this does a very good job of indicating when hot water is used.
My boiler supplies both baseboard heating and domestic hot water. I’m not sure what you have for a boiler. Do you think it can respond quickly enough when the tap is turned on to then start heating the water? As you say, it should always be kept hot enough to prevent bacterial growth.
That’s not quite correct. You want to avoid temperature sweat spots for legionella growth for an extended period. Depending on your local code that often means to heat up to a certain temperature (e.g. 65°C) every x days, while x often can be something between 3 and 7 days for example. Some regulations also want that not only the hot water tank is “flushed” with hot water at temperature x but also all pipes and faucets for example.
Holding your water tank temp always at a certain (high) level is nothing but purely for comfort. Specially heating water and night which is hardly used just to cool down over the next hours to be re-heated again can be easily considered wasting of energy/ressources (and money).
Do you have a link for the sensor?
I used the “waterproof” version of the Dallas DS18b20 temperature sensors:
There’s a good discussion here:
I just bought them off Amazon.
Note that some say you need to get the “official” or “original” Dallas version. Apparently these no-name versions are prone to early failure. For the record, none of mine (I have 5) have failed - so far. But they’re also in places which are easy to replace if they ever do. I probably would have bought the more expensive ones if they were for an inaccessible place or a critical system.
Your water is not getting hot enough to prevent Legionella bacteria from growing. You need to hit 140°F at least once a week.
EDIT: units.
to vaporize it xD
Little less is normally sufficient.
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Ha. Sorry that should have been °F
I figured you meant 140F (60C.) Mine is set between 160 and 180 F. It’s direct domestic hot water, no tank, just a heat exchanger. Any water which sits in the coils heats up to the internal temperature of the boiler pretty quickly. And any water which just passes through is chlorinated to begin with, and doesn’t have time to incubate bugs. Still, something everyone needs to consider.
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Do you mean that you only turn on the boiler when you need it or that you turn it on continuously? I think the first thing you point out.
Default is typically the second way. Plug in your boiler set the “high”/" max" temperature and forget. The internal thermostat then works to heat the water up toax (for example 65°C) and then will wait for a threshold (for example 50°C) till it heats again to 65°C.
This often is a waste of energy as - for example at night - the boiler might heat the water 2 or 3 times for nothing (just to cool down again).
The way I do it is to only heat the water when I need it.
One of the ideas I had was to check when hot water is used, so then you know approximately when hot water will be used. You can also turn on the boiler when hot water is used, so that you can ‘top up’ it.
For your case with a tiny 10 liter boiler that would make sense! For me with a 100L one not so much because I have plenty of storage (and it takes good amount of time heating).
Yeah, If you have a 100l boiler. It will take longer to heat up.
Just thinking, in case you have only a 10 liter storage do you really mind how hot the water is when opening the hot water tap? Maybe it’s enough to know that it is open/water is running. You might work that out with a simple hall sensor or something like that.
Expecting a water flow of e.g. 4 liters/minute your hot water tank probably “empties” quite quickly of hot water (or it heats up really much to “save” when mixing down).