I am considering installing Vera at home primarily to control the heating. I’d like to create a zoned heating system using the StellaZ thermostats along with the Secure SSR303 to switch the boiler on/off. In addition I’d like to use the SRT321 thermostats to report the room temperature and to get some “physical” control of the system, i.e. to boost a certain room outside the schedule built in to Vera.
Can anyone advise if all these items will work together? My main concern from researching online is that if one of the thermostats reports heat is satisfied, it would switch off the boiler even if all the other area’s require heat.
I’m not sure but are you on a forced hot water system that has a boiler keeping hot water available all the time?
Thusly, you are controlling the temperature in different zones thermostatically with valves that distribute water to those zones. Further, you are looking to add “thermostat” control to rooms within one of these existing zones?
There are many boiler control systems.
Depending on the number of zones the strategy may be different.
For large number of zones … the boiler maintains a preset temp … that may be varied by time (day/night) and outside temp.
Then zones operate independently.
For small number of zones … the zone thermostats often connect to a boiler controller. If any zone calls for heat … the boiler is engaged.
In this case the boiler is usually set to a preset off temp. Some folks add the additional control to actually control the boiler temp based on outside temp and time (day/night settings).
The system is running from a combi boiler so both heat and hot water are on demand and its currently controller with a standard boiler interlock with a simple timer with integrated temp sensor. There are no zones on the system but there are some manual TRV’s on 4 existing radiators which are the ones I am looking at replacing with electronic versions.
Ideally I would put a thermostat in each of the 4 “zones” which I would create using the StellaZ TRV’. The thermostats would call for heat when below the setpoint and switch on the boiler using the SSR303 and off when satisfied. The problem that I can see may happen is that if zone 1 is satisfied for heat, it will switch off the boiler even if the other 3 zones still require heat.
Just needed to check if the Vera can work around this by monitoring all 4 zones at once and only switching off the boiler if all 4 zones are satisfied?
So, the radiators in the cold rooms are turned off when the main thermostat is satisfied, I get it.
If you can find Z-Wave valves to replace the TRV’s you could use PLEG to control the separate zones. You would simply need a temperature sensor in each zone. You could replace the main thermostat and turn it on/off when any of the zones call for heat.
example:
Start with setting the thermostat for a slightly uncomfortable, too-warm temperature (call it 26C).
Set each of the zones to your really comfortable temperature (e.g. 22C)
Use PLEG to open the corresponding valve when that zone’s temperature is below the desired temperature by say 2 degrees.
Use PLEG to trigger when any one reaches its set point, close that valve.
Use PLEG to set the thermostat to a cool temperature (e.g. 15C) when all of the valves are closed. This will then turn off the boiler.
Use PLEG to set the thermostat back to 26C if any of the other zones call for heat. That will turn the boiler back on.
Wondering if anyone has found a conclusive answer to dannyd’s orignal problem?
I currently have 5 Stellz z running along side a Horstmann boiler control and thermostat. At the moment i have to manually set the stella’s using scenes and set the thermostat to bring the boiler on or off.
It seems that setting things up for a single stella z to trigger the boiler on or off when it requires heat or not would not be a massive problem, the problem is dealing with multiple stella-z working from the same boiler, as has been said before one stella-z may trigger the boiler to switch off while several others still require heat.
Is there a way that all stellz-z statuses can be taken in to account when the boiler is about to switch off based on the command of only one? The idea being if it sees a stella-z that is still requires heat/ is on the boiler wont shut off? Also is there a variable in the stella-z advanced setting that shows its on/off status?
I really think the stella-z is a brilliant TRV, however when its battery powered its as good as useless, i have mine all attached to 3v dc power supplies and it makes the things actually useable and a worth while addition to any heating system. (I am happy to share how I done this if anyone wants to know btw) Adding that last bit of functionality would really just top everything off!
Any help on the above would be greatly appreciated!
I’m going to reiterate the statement about using PLEG. You basically want to replicate the “all quiet” scenario, replacing motion sensors with thermostats. It shuts off the boiler when all thermostats are in the “comfortable” zone?
Hi, I use two PLEGs (probably could be combined into one, but I’m a simple man) - One sets temperature setpoints depending on time of day, status (in/out/holiday etc). The other (see below)compares the currentsetpoint with the actual temperature for every TRV device (I have 20) and then fires the boiler heating circuit, or shuts it down.
Simple but works a treat (except the laggy Stellas…see other post).
Schedules
Name On Type On Time On Days Random On Delay Off After Type Off Time Off Days Random Off Delay
s1 Weekly 00:00:00 1,2,3,4,5,6,7 None Weekly 06:00:00 1,2,3,4,5,6,7 None
Device Properties
Name Device Name Device Variable
p1 Heating Living Room Front SetpointTarget
p10 Heating_DR CurrentTemperature
p11 Heating Family room back SetpointTarget
p12 Heating Family room back CurrentTemperature
p13 Heating Family Room left SetpointTarget
p14 Heating_hall SetpointTarget
p15 Heating_hall CurrentTemperature
p16 Heating Kai’s Bedroom SetpointTarget
p17 Heating Kai’s Bedroom CurrentTemperature
p18 Heating Keaton’s bedroom SetpointTarget
p19 Heating Keaton’s bedroom CurrentTemperature
p2 Heating Living Room Front CurrentTemperature
p20 Heating_MBed1 SetpointTarget
p21 Heating_MBed1 CurrentTemperature
p22 Heating_MBed2 SetpointTarget
p23 Heating_MBed2 CurrentTemperature
p24 Heating_Office SetpointTarget
p25 Heating_Office CurrentTemperature
p26 Heating_Bed5 SetpointTarget
p27 Heating_Bed5 CurrentTemperature
p28 Heating Family Room left CurrentTemperature
p3 Heating Living Room Back SetpointTarget
p4 Heating Living Room Back CurrentTemperature
p5 Heating_Bathroom SetpointTarget
p6 Heating_Bathroom CurrentTemperature
p7 Heating_Boys_Ensuite SetpointTarget
p8 Heating_Boys_Ensuite CurrentTemperature
p9 Heating_DR SetpointTarget
Conditions
Name Repeat Expression
heaton Yes (p1 > p2) OR (p3 > p4)OR (p5 > p6) OR (p7 > p8)OR (p9 > p10) OR (p11 > p12) OR (p14 > p15)OR (p16 > p17) OR (p18 > p19)OR (p20 > p21) OR (p22 > p23)OR (p24 > p25) OR (p26 > p27) OR (P13 > P28)
heatoff Yes (p1 <= p2) AND (p3 <= p4) AND (p5 <= p6) AND (p7 <= p8) AND (p9 <= p10) AND (p11 <= p12) AND (p13 <= p28) AND (p14 <= p15) AND (p16 <= p17) AND (p18 <= p19) AND (p20 <= p21) AND (p22 <= p23) AND (p24 <= p25) AND (p26 <= p27)
My brain does not work well with coding but I’m going to have another crack at using PLEG, it looks like the reward will be worth spending the time getting my head around it!