A switch needs to be a switch

Posted on
Tue Jan 24, 2017 8:11 am
Shutter offline
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Location: London, UK

A switch needs to be a switch

In the greater scheme of things this is a general HA question, but specifically for me, now, it is somewhat Stella-Z related.

What I mean by a "switch needs to be just a switch" is how it should function as a switch independently of any smarts. Throughout my piecemeal HA install I've tried to maintain a home that can function even when Indigo, the server, the Z-Stick fail. Sure, things won't automate, but we could still turn on the light switch; the motion sensor not being able to report back to Indigo won't matter that it can't trigger a bunch of devices; my DSC alarm can still function irrespective of whether the plugin/Internet connection is working. Of course individual components can fail, but barring anything catastrophic, things still should work. And yes, I know the light switch can still fail if the Z-Wave relay/dimmer fails, but that will probably be just one light, and anybody with some electrical confidence could come in, rip it out, and wire it back up as just a dumb switch.

My desire for all this is partly for my own sanity, and also because "she who must be obeyed" doesn't care for all this. Yes, she likes when it works, and it very rarely doesn't, and I'm sure if it didn't she would miss some things that are now automated. But… well, see below.

So what's this go to do with a Stella-Z, I hear you ask? It's because the one flaw in my plan that is still giving me some anxiety is my heating. There's a button I can press to manually control the heating on the boiler receiver, but I would first have to exclude the receiver from the Z-Wave network, something that I can't expect her to do. And whilst the Stella-Zs on the radiators do not have manual control, it would be easy to remove them to then use the boiler to heat up the whole house when on, which in an emergency that is acceptable.

So what I'm wondering is what have others chosen to do? The way the Stella-Z plugin works means one can't manually control the boiler receiver because the plugin is monitoring the device and will counter act the manual command.

I can't be the only one who's thought this. Some sort of manual bypass control on the boiler? Ideas anyone?

Simon

Posted on
Tue Jan 24, 2017 12:47 pm
RogueProeliator offline
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Re: A switch needs to be a switch

So what I'm wondering is what have others chosen to do? The way the Stella-Z plugin works means one can't manually control the boiler receiver because the plugin is monitoring the device and will counter act the manual command.

I know nothing of the Stella-Z stuff, but based on this statement you CAN make a manual command? If you concern is an emergency and Indigo were down, the plugin wouldn't be running to "counter act the manual command", would it?

Posted on
Tue Jan 24, 2017 1:25 pm
autolog offline
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Re: A switch needs to be a switch

RogueProeliator wrote:
... If your concern is an emergency and Indigo were down, the plugin wouldn't be running to "counter act the manual command", would it?


Exactly :)

What Z-Wave boiler switch are you using?
If it is a Secure SSR303 (for example) this will go into fail-safe mode if Z-Wave communication is lost. You can then use the buttons to turn the boiler on and off. :)

Another alternative would be to wire a switch in parallel that could act as a manual override. :)

Posted on
Tue Jan 24, 2017 1:36 pm
Shutter offline
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Location: London, UK

Re: A switch needs to be a switch

Don't I feel dumb. :oops:

Now that I'm back home I've tested if the boiler relay allows manual control with the plugin disabled but it still included with the Z-Stick. And it sure does. So what I think I'll do is create an option on my control page to disable the plugin and allow manual control in case of an emergency.

Sometimes you just need to talk to the universe and the universe presents an answer. Thanks.

Posted on
Tue Jan 24, 2017 1:38 pm
Shutter offline
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Re: A switch needs to be a switch

Hi Jon,

Yes, it's the Secure SSR303. I got it into my head that I should wire in some hardwired override switch, but I don't really need to.

I think my next task is to create a "How to use the house" emergency handbook. :)

Posted on
Tue Jan 24, 2017 6:17 pm
jay (support) offline
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Re: A switch needs to be a switch

Shutter wrote:
Don't I feel dumb. :oops:

Now that I'm back home I've tested if the boiler relay allows manual control with the plugin disabled but it still included with the Z-Stick. And it sure does. So what I think I'll do is create an option on my control page to disable the plugin and allow manual control in case of an emergency.

Sometimes you just need to talk to the universe and the universe presents an answer. Thanks.


I'm confused - if Indigo isn't working, which is the scenario in which you need manual control, then by default the plugin isn't running either, so the manual control should work. Right?

Jay (Indigo Support)
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Posted on
Wed Jan 25, 2017 12:58 am
sgbirch offline
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Re: A switch needs to be a switch

Shutter wrote:
My desire for all this is partly for my own sanity, and also because "she who must be obeyed" doesn't care for all this. Yes, she likes when it works, and it very rarely doesn't, and I'm sure if it didn't she would miss some things that are now automated. But… well, see below.


OMG ... this sure sounds familiar. I am accused of unnatural obsession because of my interest in technology. The other men in the family who watch football obsessively and have no conversational ability other than football are considered normal.

I recently upgraded my system to include heating, which was a huge challenge. The house has three floors, each floor was originally zoned with its own thermostat, all controlled from a multiple channel programmer (timer). I chose Devolo TRVs instead of Stella because they have a temp setting at the device. Devolo sells a rebranded Danfoss with new firmware for reporting temperature back to Indigo.

Each floor has its own zone valve in the boiler room, originally activated by the thermostat/controller for that floor. When the zone valve is activated (to supply hot water to a zone) and fully open it signals the boiler to supply hot water.

Each of the floors looked like this:

controller --> thermostat --> water valve --> boiler

So, the boiler fires when the controller is on, the thermostat calls for heat, and the zone valve is open. Simple?

Finally, every radiator had an old fashioned TRV on it to regulate the temperature in each room.

The challenge was (is) huge.

1. How to automate so SO can control the system
2. How to isolate unused rooms
3. When to turn on the boiler for each floor

The first decision, like yours, was to put the system in parallel. This means I can shut off the entire z-wave system and still have heat. My approach was to put a zwave switch in parallel with each of the original floor thermostats. In addition, three zwave sensors detect when the original programmer (timer) activates. The family is used to pressing buttons on the programmer to turn on the heating.

The next step was to turn all thermostats to zero, disabling them. With that done, the only way to request hot water is via a command from Indigo to the switch wired in parallel with the disabled thermostat.

Effectively:

controller --> Z-Wave switch --> water valve --> boiler

I then wrote software for Indigo to monitor the temperatures reported by each TRV to determine when to light the boiler, ill probably replace this with the Stella plugin since it is better quality than my quick and dirty software. But I needed to experiment to solve a number of issues related to the multiple zone problem.

If (when) the Mac failed and Indigo goes offline, reverting to manual operation is no more exciting than turning up the old thermostats.

The final part of this revert to manual was a master on/off lightswitch wired to provide power to the zwave sensors and switches mentioned above. That one lightswitch cuts power to everything, effectively reverting back to a fully manual system. I don't expect the SO to use this switch, but it is simple enough in an emergency.

The Devolo TRV is quite happy to operate without a-wave commands and can have their temperature set manually. When used in this manner they are identical to the old manual TRVs.

So .. if the Mac crashes and Indigo fails, my SO can just turn up the house thermostats and she has heat. She doesn't even need to turn off the z-wave master switch (lightswitch).

Assuming the master switch was still turned on after Indigo goes down, it is possible that one of the zwave switches is left on, calling for heat. This isn't a disaster since the boiler has its own thermostat and will turn on and off as required.

The point is that the Indigo system must fail safe. In this case, fail safe means the SO can still heat the house.

Sometimes I wish I'd been born loving football instead of technology, life would be more harmonious.

Steve









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Posted on
Wed Jan 25, 2017 3:20 am
Shutter offline
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Re: A switch needs to be a switch

jay (support) wrote:
I'm confused - if Indigo isn't working, which is the scenario in which you need manual control, then by default the plugin isn't running either, so the manual control should work. Right?


Jay,

As I said, I feel dumb for asking. I was thinking that it being still tied to the Z-Stick might mean it didn't allow manual control, but that's a function of the plugin not it being included. Tested and it works.

Posted on
Wed Jan 25, 2017 3:31 am
Shutter offline
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Re: A switch needs to be a switch

Steve,

Your setup makes my head hurt. :wink:

I do sometimes say to myself why do I do this. It's not that it's generally not stable, more that it's a rather complex system of many parts. I do know that for the next house I'll be designing this from scratch and it would like different to what I have now.

Posted on
Wed Jan 25, 2017 10:16 am
jay (support) offline
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Re: A switch needs to be a switch

Shutter wrote:
As I said, I feel dumb for asking. I was thinking that it being still tied to the Z-Stick might mean it didn't allow manual control, but that's a function of the plugin not it being included. Tested and it works.


Ah, gotcha. Glad it's all working! I have to say, the heating controls over there in the EU are significantly more complex than here in the US... :?

Jay (Indigo Support)
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Posted on
Sun Jan 29, 2017 5:37 am
sgbirch offline
Posts: 93
Joined: Sep 11, 2013

Re: A switch needs to be a switch

Shutter wrote:
Steve,

Your setup makes my head hurt. :wink:

I do sometimes say to myself why do I do this. It's not that it's generally not stable, more that it's a rather complex system of many parts. I do know that for the next house I'll be designing this from scratch and it would like different to what I have now.


Yes, it makes my head hurt too :smile:.

There are all kinds of problems, the latest being the realisation that the TRVs start to shut when they get close to their setpoint temperature. That means the zone never stops calling for heat, resulting in a large fuel bill. I think I solved that by creating a virtual room in Indigo, all enabled rooms have their temperatures and set points averaged. The call for heat temperature is then computed as one degree lower than the average set point. The system then makes a single request for heat.

The zone valves are then opened, but only for the zones participating in the average. This seems to sync things better so zones don't call for heat at different times.

One thing I have found, the Devolo seems to be quite brilliant at holding the requested temp as long as hot water is provided. It is a Danfoss design, those guys clearly know how to build heating controls. Unlike me!

Regarding your system, you said your next house will be different. What would you change?


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Posted on
Sun Jan 29, 2017 6:50 am
Shutter offline
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Location: London, UK

Re: A switch needs to be a switch

sgbirch wrote:
Regarding your system, you said your next house will be different. What would you change?


Fewer battery devices and a heating system designed from scratch, with hardware zones instead of relying on smart TRVs. I'm also thinking that I would like a system that I don't have to maintain, even if it means paying an installer to fit and configure it all for more.

A system that I can modify, but that one where the lighting, heating, and security is hardwired and uses dedicated hardware/software. I would still like to have a system where I can modify the triggers and schedules as our usage changes. And ideally on that integrates with Indigo, because then it gives me the option to add devices, say Z-Wave or Homekit, for non-critical systems when I think they might be useful.

Does such a system exist? No idea. Seeing as I wont be doing this for a few years anyway I don't have to think about it too much. I like the idea of KNX, albeit a bit pricey. Maybe by the time I do all Indigo will support it. I'm just finding that I have to think about my current system too much. It all works just fine with very few issues, but I do have to constantly keep an eye on it. And I've just had to put together a 6 page document on how the house works in case of emergency the other half knows what to do, of if anything happens to me someone can come in and know where all the relays and dimmers are. :cry:

But I'm in no rush to change right now.

Posted on
Sun Jan 29, 2017 7:06 am
sgbirch offline
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Re: A switch needs to be a switch

Shutter wrote:
I'm just finding that I have to think about my current system too much. It all works just fine with very few issues, but I do have to constantly keep an eye on it.


It sounds like we are on the same page. My system works well enough but every so often a pin sticks under a TRV and the room doesn't heat up, or a sensor misses the transition of the controller output. Not often, but it is a long way from the reliability I'd like.

I feel that I'm fiddling with a bunch of gadgets rather than building a robust solution.

But it's better than it was before, rooms were always too cold or too hot and it burned heating oil like there was no tomorrow.

Steve



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Posted on
Sun Jan 29, 2017 7:45 am
Shutter offline
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Location: London, UK

Re: A switch needs to be a switch

This year I"m actually really happy with the way the heating has been going. Jon's Stella-Z plugin has been working really well, and I've found a nice balance of settings, which mean I never have to tweak them, other than start a schedule earlier if I'm home before it's due to start. It did help that we further insulated two rooms that we felt never got warm enough. I also replaced all the l valves that had sticking pins, and I make sure I don't let the Stella-Z batteries ever drop below 25% before replacing them.

Posted on
Mon Jan 30, 2017 2:19 am
sgbirch offline
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Re: A switch needs to be a switch

Shutter wrote:
This year I"m actually really happy with the way the heating has been going. Jon's Stella-Z plugin has been working really well, and I've found a nice balance of settings, which mean I never have to tweak them, other than start a schedule earlier if I'm home before it's due to start. It did help that we further insulated two rooms that we felt never got warm enough. I also replaced all the l valves that had sticking pins, and I make sure I don't let the Stella-Z batteries ever drop below 25% before replacing them.


I am finding there are fewer calls for heat if the average temperatures from all of the enabled TRVs is compared to the average of set points for the same set of rooms.

It seems to do a better job of synchronising the rooms so they all call for heat at about the same time rather than on demand. I was trying to find a way to stop the boiler running just because one TRV is calling for heat.

Have you experimented with this type of algorithm at all?


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