Hello,
i was wondering what can be controlled/ how in water boiler, if the boiler “is dumb” device, all i can do for a saving is to power it completely off when i know i will leave a house for lets say more then 2-3 days? Can i control power off/on via Qubino Flush 1D Relay?
I think i have that model
i was thinking to install Qubino before L wire so i can control power on/off.
any ideas are welcomed
thanks
can anyone advice here? thanks
i was thinking to remotely power on/off via that relay which can handle 2300W
Qubino ZMNHAD1 Flush 1 Relay Switch Z-Wave Module for Smart Home up to 2300 W
It looks to me that the heating element draws up to 2500W so that relay is not suitable
This Zwave one will do 16A (3680W @ 230V)
or this one:
or zigbee:
or wifi:
I’ve not bought their brand but used the shop for years. Look around, there’s probably others, they were just the 1st I found
Perhaps if you have access to thermostat wires, you could instead use a dry contact relay to control the on/off signal. Like the Qubino Universal Relay, or Fortrezz MIMO Lite.
Also, keep in mind that, if this is for drinking water, it isn’t recommended to lower the temperature below 120 degrees Fahrenheit due to the risk of Legionnaires Disease (Legionella bacteria).
@new_west_geek hm i wanted to power offf when i go for vacation etc like more then 3days out of house.
What do you mean by thermostat wires? could you elaborate a bit? thx
but as per your saying it seems i will need to get rid of all water which is there stuck for 2 weeks with no heating.
I guess the more appropriate term is “aquastat” when it’s used on a water heater. But it’s the same concept as a thermostat. It tells the heater when the temperature drops below a certain threshold (determined by a dial), then closes the contacts that activate the heating. In the diagram you showed, it says there’s an “EIKA v01 thermostat”. So, what I’m saying might be possible is to replace, or interface with that thermostat using a dry contact relay. If you can figure out which contact are being closed when the thermostat calls for heat, then those are the ones you would connect to using a relay.
Your initial idea of using a high voltage relay might be possible too, but if it were me I’d rather deal with the thermostat than switching the overall power of the heater.
I’m not an expert on Legionella and such. But I’m just relaying what I’ve read when looking into this myself. A water heater left with luke-warm water will encourage dangerous bacterial growth. And perhaps that’s why you don’t find a lot of products available off-the-shelf to automate water heaters. Done wrong, it can be a hazard.
got your point …
so basically these water heaters should never be powered off for a long time… well mine is with water already off 12 days ;-(
There probably is a safe way to handle turning it off for long periods. I’m sure lots of people do it. I’m just saying, do your research on that part of it.
If you do decide to go the direction of a smart relay, then google’ing “z-wave contactor” might help. That seems to be a term used for the higher voltage ones.
Good luck!
maybe i can cut it on that Thermostat circuit … dunno , with contractor seems not that easy as i thought.
other thing would be that issue with bacteria … that you mentioned.
@new_west_geek seems you were right,
so maybe it has to be somehow remotely controlled instead of turning off just lower tempreature to lets say 45 Deg, but no idea how to do that?
thanks
Right… so now I’ll come clean… I’ve actually done this with my water tank already. 
My solution won’t work exactly for your situation though. I have an indirect-fired hot water tank which is heated by a separate boiler.
To sense the temperature of my water tank, I’ve used a Fibaro z-Wave Smart Implant connected to a DS18B20 temperature sensor. There was enough room in the drywell of the aquastat to slide the sensor in alongside the tank’s existing sensor. So, in theory, I can switch back to using the water tank’s own aquastat in the future if I need to.
Then, instead of connecting the existing hot water tank’s aquastat to the boiler controls, I’ve used a z-wave dry contact relay (Fortrezz MIMO) connected to the dry contact inputs on the boiler.
Tying everything together is a Generic Thermostat entity in HomeAssistant, using the sensed temperature from the DS18B20 and the dry contact relay as the on/off switch.
I’ve only had it this way for a few months, and my goal is quite conservative. I set back the temperature just a few degrees overnight and then bring it back up in the morning (always keeping it above a safe temperature to avoid the potential bacterial issue).
uhm uhm cool.
well but still not clear how to apply on my case… as one more thing i have only 8h from 24h active power that can heat boiler.
i mean no clue how to control temperature in my case - maybe there is some device for that?
oh dear, i think they measure temp in that boiler with that thermostat
https://www.elny.cz/dz-drazice-okc-okce-termostat-kapilarovy-bojler/d-83415/
My approach is similar but different 
Instead of switching it off, I heat it with solar power from our PV system.
The setup is I use shellypro1 and a contactor to switch the heater from electricity instead of exporting to the grid.
with some simple automation in HA
To avoid the legionella issue I set my thermostat to 65°
Trigger
platform: state
entity_id:
- schedule.hlp_water_heater_time
- switch.shellypro1_switch_0
condition: numeric_state
entity_id: sensor.battery_state_of_capacity
above: 90 %
enabled: true
Action
type: turn_on
device_id:
entity_id: switch.shellypro1_switch_0
domain: switch
delay:
hours: 0
minutes: 45
seconds: 0
milliseconds: 0
type: turn_off
device_id:
entity_id: switch.shellypro1__switch_0
domain: switch