I then wired the wires that used to go to the Nest to the NO (Normally Open) pins of RELAY1
This way, when the nest kicks is for downstairs, the boiler kicks in and openHAB knows through MQTT
I can also turn on the boiler via the temperatures sensors upstairs which turn on the radiator valve which in turn turn on the boiler.
Thanks @vzorglub I missed that you have Nest thermostat at home as well. There are quite expensive this days as I can see. I’m debating if I should rely on my own temperature sensors dotted around house (mostly DHT22/Sonoff) but i know that i could left house cold if my openHAB is down for any reason one day. I travel around country every few months so it could be disaster if that happens and I’m not around in the middle of winter ( = & )
Then I would add a DHT22 to the Electrodragon and a TASMOTA rule that if the temp iss below say 5c then kick the boiler ON for 1 Hour and send a message to all the other sonoffs to open their valves.
It is important in this case to have the mosquitto broker on ANOTHER machine than the openHAB server. My broker runs on PIzero. Does only that. Plugged into a powerbank good enough for 4 hours of continuous operation.
I may need to consider splitting my broker from OpenHAB I think it’s good idea. I use OpenHABian assuming it can we done ?
With regards to thermal actuators not sure which brand to choose yet:
Two wire
Four wire
230VAC or 24VDC
Any particular brand worth looking ? There is tons of them on the market at the moment.
MDAR
(Stuart Hanlon, UK importer of Velbus hardware)
85
Personally, my answers would be…
Two wire - only if you just need the valve opening
Four wire - Great if you want to use the “fully open” microswitch to confirm the valve opening, or “call for hear”
230VAC or 24VDC - Totally up to you, no advantage either way. Unless… you want a sub 50v system, which may mean different / simpler building codes to comply with.
Any particular brand worth looking - In 8 years, I’ve only heard of 1 microswitch failing in an Emetti WTA.
Is there an actuator based on 5V? Something what can run on battery?
I have already read through Any TRV suggestions? but nothing mentioned of there as well.
So far I find only DIY tutorials:
Not that I’m aware of. These types of actuators require constant power when “on”.
I very deliberately did not want anything battery powered.
There are products like the Shelly H&T, which are battery powered temp/humidity sensors, but they are hard-coded to only read & report once every 10 minutes. I wanted reporting more regularly than that - my bathroom sensors report every 30 seconds, and as well as being used for heating control, also are used to operate extractor fans based upon humidity changes - a sensor reporting every 10 minutes would not have been suitable for that, for me.
Hello Garry,
I don’t suppose you have an example of your sitemap, please?
I’d like to implement your code with my underfloor heating, I have a wet system upstairs and down that runs on analogue thermostats and needs updating to make it more efficient.
I believe the regular radiator valves are not just open or closed but operate on a continuum of how much they are open (when you turn them, the pin inside seems to move a bit more up or down) - or have I misunderstood how they work? These actuators, which seem to be the same as on my underfloor heating system, are only either fully open or fully closed. Is this a limitation? Are there any actuators where the degree of openness can be controlled?
As regards using humidity sensors in the bathroom to control the moisture exhaust fan, what has experience with them been like. What’s the best location to place them? Inside the shower? In the bathroom on the ceiling outside the shower cabin? Do you use a differential measurement (i.e. humidity in the bathroom as compared to humidity in the rest of the house) to decide when to shut off or just the absolute measurement in the bathroom? Any recommendations as to the experience you’ve had with various humidity sensors, exhaust fans and actuators used to control them?
No. They mechanically shut off at a temperature that you “enter” with the valve. The amount of water to flow is usually statically set/limited at installation time.
As soon as both are OH-controlled, you can easily adapt thresholds and fan activation times over time, so just do.
The typical twisty style thermostatic valve heads vary the flow through the one valve coarsly via the manual adjustment, and then finely based upon current temperature - usually a small bit of wax will expand or contract based on the current temperature. They’re designed really to allow some flow through the radiator all the time the heating is on, the more flow you allow, the more heat is pumped into the room.
As I’m just allowing the radiator to be on or off, I don’t really control the amount of heat the radiator outputs, just its duration. I can adjust the flow using the lockshield valve on the opposite side to have a minor influence - I could also look into “pulse width modulating” the actuator simulate a percentage of opening, but I’ve not had the need to yet.
With regards to the humidity sensor and extractor fans, as has been said, it’s all controllable via openHAB, so I can modify thresholds. I currently have it that if the humidity hits 100%, or the average over the last 5 minutes in the bathroom alone is over 75%, the fan will come on, and it will remain on for 10 minutes after either it is no longer 100% humidity, or until the average over the last 5 minutes is below 75%.
My Wemos D1 Mini & DHT22 have been just fine for the 7 months they’ve been installed, reporting temp/humidity every 30 seconds, and I’m using a Sonoff basic for the extractor fan, as I had one spare. If I were buying new, I’d buy a Shelly, because they don’t need opening, soldering and reflashing to support MQTT like the Sonoff does.
Hi Garry, Thanks for sharing your setup, you have inspired me to do something similar in our home.
I have copied across your items and rules to test on my system before installing actuators however I have noticed an issue with the rule "Check heating actuators every 5 minutes"I If a temp sensor is disconnected from the network openhab will give it a NULL value and the rule will fail due to this.
I cannot work out how to edit the rule so that it continues the rule and report this error (through notification of log info), unless I use the expire binding and set the disconnected temp sensor to report 999 after 10 mins of inactivity.
Setting to 999 ensures that the rule doesn’t break and also the heating isn’t turned on when it is not required.
Are you able to assist with the rule when a temp sensor is NULL?
Hey Garry,
Thanks for the reply. I am actually using the update code from post 75 however there is still a issue.
2020-06-23 14:00:05.231 [ERROR] [ntime.internal.engine.ExecuteRuleJob] - Error during the execution of rule ‘Check heating actuators every 5 minutes’: Could not cast UNDEF to java.lang.Number; line 26, column 25, length 15
…
FYI on another note and for anyone else who may struggle to get this working, I wasn’t able to get your rule working without changing the below
i.sendCommand(newState)
to
sendCommand(i.name, newState.toString)
= 
& 
)
