Fibaro Heat Controller - boiler communication

[Guest Murakami78]

Hi to everyone 

I've seen this thermostatic radiator valve... i've read all the information in the fibaro site but I haven't seen nothing about the boiler comunication... How this system Will speak with the boiler. I imagine that when one or more valve ha open... another device should comunicate with the boiler to turn it on... or not? And when all' the valve are closed the boiler must be shoutdown.  

I'm wrong ?

 

Excuse me my bad English... I'm italian 

 

Luca.

[petergebruers 1,268]

Your boiler will control the temperature of the water in the boiler. If all valves are closed, no heat is used so the heater of your boiler does not turn on. If valves open, the water temperature in the boiler drops. If it reaches a certain threshold, your heater turns on. The electronics on your boiler control this without user intervention. Boilers have either a fixed temperature setting or use an outdoor probe, to determine the optimal water temperature. Plus some settings, or it might be "self learning"... I am assuming all your radiators have thermostatic control, but not necessarily Z-Wave. Summary: you do not need a room thermostat, and you do not need communication with your boiler, but all radiators should have some sort of TRV. Does this explanation help?

[Guest Murakami78]

Hi, thanks for the reply.... I live in Italy and my  boiler have a contact to start it. It have boh a temperature set and a contact to start the water radiator. If you don't colse the contact the boiler don't start... and on the contrary if you close the contact to start the boiler with all the radiator valve closed.... the boiler Will damage itself

Have I Made myself clear ?

[petergebruers 1,268]

Your boiler does not have a thermal control and/or limit? That would really surprise me. Please post a link to the technical documentation. I am not going to make any assumptions regarding your setup... certainly not if you tell me it does not have temperature control...

Edited October 16, 2017 by petergebruers

[Guest Murakami78]

Every boiler that I know, have a temperature control where you set the temperature that you want in the water present in the radiator circuit (for example 50ºC or converted in K is 323) an also have a contact that Will be connected to the thermostat.

The temperature that you want in the house must be setted in the thermostat.

When the thermostat read a temperature in the house that is lower than which one you have setted in itself... it Will close the boiler contact and the boiler Will start warming the water present in the radiator Circuit and in the same time the boiler start a water pump that make circulate the water present in the radiator Circuit. 

Ecc ecc...

[petergebruers 1,268]

Well, set your boiler to 50 degrees. Disconnect the room thermostat. Close the contacts permanently. Your boiler will make 50 °C hot water all the time, but that is not a problem, is it? Your pump might run all the time. Older pumps on older boilers certainly do, it will wear out sooner. Also, pressure should not be a problem, if your heating circuit was designed for thermostatic valves. If your boiler has a fairly recent pump, the pump will generate a constant pressure, adjusting to the opening and closing of the valves and that is more efficient.

 

Each TRV will set the temperature in its room. With Z-Wave, you can set a lower temperature at night. Or if you are on a holiday, set all rooms to 16 °C. Your boiler will still produce hot water for the radiator circuit, but because it is not used, it only has to compensate for the heat loss through the insulation of your boiler... You *might* save an extra % by turning of your boiler & pump completely. Some people have written scripts to control their boiler contact, based on temperature and the assumption that their script is able to determine when the boiler should be "on"... I think it is possible, but not easy... The boiler knows best... If the water is < 50 it heats up, if it is > 50 (with some hysteresis, and taking into account cycle times that optimize the efficiency of the burner!) it will stop heating... If you add a room thermostat, that thermostat will override your TRVs, it will not work well.

 

I'll link a few of my older posts regarding this issue (but please read the complete topic for context!), they might explain why I am so sure about why my solution works really well:

 

 

 

 

 

If it is still unclear after reading those topics, feel free to ask more questions. Also, if you do not agree, or have some information that I forgot to include, please tell me how I can improve my answer. We can all learn something! This question gets asked every year, in autumn... So it is the right time of year!

[Guest Murakami78]

I've read some of post that you have posted....

The solution to remove the thermostat and keep the boiler contact always closed I Think that isn't a good idea... at least with all boiler.

Because many and many hydraulic said to me that starting the boiler (closing the contact) with the radiator Circuit closed (all the thermostatic valve closed) Will damage the boiler itself. 

And for me there is some kind of logic... if the Circuit is closed and the water pump is off the boiler Will warm a static water... nobody take away the heat.

I don't know how work a modern boiler but I'm almost sure that doing this in my system Will damage the bolier

[morpheus75 77]

the way i have used these in the past is as follows:

 

i have a central thermostat to control the general temp in the hallway and downstairs rooms. On the first floor bedrooms i have used these valves when i was testing them.

the thermostat keeps ground floor at a desired set point which i set using schedules. As no one is upstairs during the day i dont want any heating on upstairs so i adjust the setpoint of the TRV upstairs to about 15 which is effectively off for me. so the heating is effectively on downstairs only.

after school time i change the setpoint back to around 21 to ensure that the heating does come on upstairs if the boiler is on, but the temperature measurement is still taken from the downstairs thermostat.

These fibaro stats have more funcionality than the Danfoss that i used, but you still need something to activate the boiler. i have installed a relay to override my thermostat when i am testing these valves and write scenes to monitor each room and then activate relay if needed to create a room by room heating system

[Momos 103]

@Murakami78 Yes you are correct in the statement that  if the boiler will warm a static water it might be damaged. 

BUT, there is a very simply solution for this which i am using for a long time. 

Like @petergebruers said : set your boiler on 50 degrees and disconnect the room thermostat and close the contact permanently.  Make the heating schedule for all TRV's.  Keep one radiator - in my case a towel rack in the bathroom - without TRV, with  a manual valve that you close almost to the minimum, just to ensure some water flow between boiler and radiator.  This way the boiler will function properly and all the heating will be done according to the schedule.  The pump will run continuously - might adjust its speed if it is a variable speed pump and its set as such in the boiler configuration.  The gas valve in the boiler will also adjust depending on how much heat the boiler has to put out to heat the circuit to 50 degrees. 

 

[petergebruers 1,268]

45 minutes ago, Murakami78 said:

I've read some of post that you have posted....

The solution to remove the thermostat and keep the boiler contact always closed I Think that isn't a good idea... at least with all boiler.

Because many and many hydraulic said to me that starting the boiler (closing the contact) with the radiator Circuit closed (all the thermostatic valve closed) Will damage the boiler itself. 

And for me there is some kind of logic... if the Circuit is closed and the water pump is off the boiler Will warm a static water... nobody take away the heat.

I don't know how work a modern boiler but I'm almost sure that doing this in my system Will damage the bolier

 

I can only try to explain, why it works. If you do not accept the explanation, there is nothing I can do.

 

If you do not think it is safe, then do not implement it! It is your house! I'd rather you have ignore my advise and err on the safe side!

 

I do not have a room thermostat. I use Danfoss TRV with and without Z-Wave like that since 2013. I have to admin it: I have an expensive Viessmann computer controlled system, it has lots of configuration options and lots of diagnostics. Please note it is an oil burner, and this has an interesting side effect! My boiler ALWAYS heats up to at least 40 °C. It *never* turns off. It does that, because condensation can be corrosive, and by keeping it at least 40 °C it avoids this corrosion problem. In the manual they say: NEVER turn of the computer, just let it do its job... You say you cannot turn on your system permanently, my systems says it is quite the opposite...

 

Please check with your installer if my solution is compatible with your setup... It will give you maximum comfort, maximum control in all rooms!

 

29 minutes ago, morpheus75 said:

the way i have used these in the past is as follows:

 

i have a central thermostat to control the general temp in the hallway and downstairs rooms. On the first floor bedrooms i have used these valves when i was testing them.

the thermostat keeps ground floor at a desired set point which i set using schedules. As no one is upstairs during the day i dont want any heating on upstairs so i adjust the setpoint of the TRV upstairs to about 15 which is effectively off for me. so the heating is effectively on downstairs only.

after school time i change the setpoint back to around 21 to ensure that the heating does come on upstairs if the boiler is on, but the temperature measurement is still taken from the downstairs thermostat.

These fibaro stats have more funcionality than the Danfoss that i used, but you still need something to activate the boiler. i have installed a relay to override my thermostat when i am testing these valves and write scenes to monitor each room and then activate relay if needed to create a room by room heating system

 

Thank you for sharing!

 

Same advise to you... Please check with your installer if my solution is compatible with your setup... It will give you maximum comfort, maximum control in all rooms!

You can remove the room thermostat, remove the extra relay and drop the Lua code... No need to think about when to override your thermostat and stuff like that.

 

1 minute ago, Momos said:

@Murakami78 Yes you are correct in the statement that  if the boiler will warm a static water it might be damaged. 

BUT, there is a very simply solution for this which i am using for a long time. 

Like @petergebruers said : set your boiler on 50 degrees and disconnect the room thermostat and close the contact permanently.  Make the heating schedule for all TRV's.  Keep one radiator - in my case a towel rack in the bathroom - without TRV, with  a manual valve that you close almost to the minimum, just to ensure some water flow between boiler and radiator.  This way the boiler will function properly and all the heating will be done according to the schedule.  The pump will run continuously - might adjust its speed if it is a variable speed pump and its set as such in the boiler configuration.  The gas valve in the boiler will also adjust depending on how much heat the boiler has to put out to heat the circuit to 50 degrees. 

 

 

Thank you Momos, ...

[Momos 103]

@petergebruers I got a Viessmann Vitodens 300 and all  the heating curves are set only according to the external sensor temperature.  Disconnected the central thermostat, a Vitotrol 300 a long time ago. All works smooth   Hardest part was to set the heating curves.. 2 months of trial/error to get optimum curves for my house lol

 

[petergebruers 1,268]

10 minutes ago, Momos said:

Hardest part was to set the heating curves.. 2 months of trial/error to get optimum curves for my house lol

Confirmed

 

I'd like to point out that this is only needed to optimize efficiency, so people should not be too scared by this. You can start by setting your boiler to a fixed temperature that is high enough...

I'm in Belgium and water temp determined by the computer is 42 °C right now. Boiler temperature: 69 °C. Huh? Yes, that is correct, I have a mixer valve, so the oil burner can run for a longer time and be more efficient, while the mixer valves keeps the water at a lower temperature. Normally that setup is for underfloor heating but as things go, the building project has been "indefinitely delayed". My Vitotronic 200 is from 2001. Zero issues. No, wait, the clock drifts a bit (no internet connection) 

 

An optimal solution depends on so many factors... Got extreme insulation and cheap electricity? Why not go all-electric... Cheap gas? Different boiler... Used for tap water too? Connected to a solar boiler? Endless possibilities... But you probably do not need/want a room thermostat with any of those solutions (but thermostats in every room, or what you suggested in your previous post, one room that acts as a bypass. Check with your installer).

[sirKitKat 24]

I suspect there are hydraulic by-passes in the market that bypass all radiators if the pressure gets to high (like when all TRV are closed) to keep the water circulating.

[petergebruers 1,268]

5 minutes ago, sirKitKat said:

I suspect there are hydraulic by-passes in the market that bypass all radiators if the pressure gets to high (like when all TRV are closed) to keep the water circulating.

 

Yes. If you already have (mechanical) TRV, your installation should already have one. I'd say it does not hurt to double check that... You will see something that connects the hot and cold pipes, close to the boiler. Newer systems have one inside the boiler cabinet.

[pikachu 0]

I am sorry to refresh such old topic, but I encountered the same problem with controlling the boiler ignition and heating up the water in it.

I know the approach to that task by setting hysteresis manually in the Home Assistant and determining the need of providing the heat by the boiler.

My home automation system is based on Home Assistant with Z-wave module that acts as server and I have 3 Fibaro Heat Controllers in each one of the 3 rooms, each one of heat controllers has connected external temperature sensor.

I spent past few days checking how to turn on the boiler effectively - to not wear out the pump inside it excessively and to make it energy eco enough. I have written myself few scripts and automations that allow doing this by basically manually setting up hysteresis and comparing it with target/actual temperature. The problem I encountered is the actual temperature that does not grow above set up temperature in Heat Controller - which means the hysteresis would not work as it should, so instead of adding 0.2 Celsius to the target temperature and comparing it with actual, I subtracted 0.2 from target temperature as the Up level of hysteresis, and subtracted even more for Down level of hysteresis (for example 0.6C. So bigger overview example actual temp: 21.0C, with hysteresis set: 20.8C-20.4C with actual set up). That made me research more and I discovered parameter bit that can be set up in Fibaro Heat Controllers with called "Heating Medium Demand Reports" (I use Z-wave JS UI). That allows Fibaro Heat Controller to set a flag called "Provide Heat" to '1' when it decides it wants hot water to flow inside the radiator and heat. It is set to '0' when it decides it doesn't want to heat anymore.

That would be great option to use instead of using manually set up hysteresis in outside system such as Home Assistant that I use. Problem is - we don't know hysteresis, we don't know the heating scheme that those Controllers follow. This is why right now I do more tests with Home Assistant verifying the graphs and tracking the bit Provide Heat.

That would make everything so easy to turn on/off the boiler, but I don't know much about that parameter bit as it appeared in Fibaro Heat Controller OS v4.7.

If anyone knows more about it, I would love to know your experience/opinions!

 

Thanks in advance.