Home heating automation

s7ryf3925pivug

deezell wrote: »

Smart predictive control, infinitely variable time and temperature schedules, geo-location, Smart TRV integration, Open window sensing, OpenTherm connectivity for OT equipped boilers, daily graphical reports, Home and Away mode, HW control, Manual mode with choice of termination method. Echo, Home, google Assistant, Apple Homekit, Smartthings, IFTTT integration.

Different models have some or all of these features, Drayton wiser, Tado and Netatmo have integrated TRV capability, but with third party control (Echo, etc), it's possible to operate different systems with a stored list of commands to the different devices, so say a NEST owner via an Alexa call could turn on Tado TRVs, and instruct the main Nest stat to fire the boiler in order to supply the Heat. Similar has been done by posters here and elsewhere, often using IFTTT and the now obsolete Stringify.
If you have two distinct heating zones and HW, separated by motorised valves, (I suspect you may have a standard EPG style zone controller and are attracted to the plug in Ember as a result?), then the Draton Wiser is currently the best value out there for it's KIT 3 two thermostat plus HW control system.

Getting a new central heating system altogether. The engineer said he could install ember when I said smart controls.

Some of this sounds great. Smart TRVs didn't occur to me. Already find the equivalent functionality offered by a dyson smart fan heater useful.

deezell

Penny Huge Clock wrote: »

Getting a new central heating system altogether. The engineer said he could install ember when I said smart controls.

Some of this sounds great. Smart TRVs didn't occur to me. Already find the equivalent functionality offered by a dyson smart fan heater useful.

Go for for it. Some plumbers run a mile for smart systems, but as this is an "Engineer", then he should have the smarts to be able to connect something better than Ember. Sometimes they call in a sparks for this, but in the end it is the same wiring than a conventional manual system, or less as the stats can be wireless.
The Drayton Nest and and other Smart stats can connect wirelessly back to their controller, so a single controller or combined controllers (depending on brand) are used to call the boiler and open the zone valves, same as the ember or manual controllers. Make sure to get TRV valve bodies on your rads if not already there, you'll need these to put smart TRV heads (or even manual heads) on. The real trick with smart TRV equipped systems is that a smart TRV, when it opens to heat a room, will call the boiler to supply the necessary heated water through the associated controller. manual TRVs just limit a room temperature, but can't initiate a heating call by themselves.
If you only get TRV valve bodies on the rads, with or without manual TRV 'knobs', you can easily install the Smart TRVs later yourself. Drayton smart TRVs are currently only £39.99 on Amazon, So you could squirrel away a half dozen of these for £240, about €280, pop them on at your leisure and add them to the original Drayton Wiser Kit 2 or 3 app. I doubt if you'd get much change from a grand if you asked for the installation of six smart TRVs in addition to your existing upgrade quote, so this way will save you a buck, but I could be wrong.

s7ryf3925pivug

deezell wrote: »

Go for for it. Some plumbers run a mile for smart systems, but as this is an "Engineer", then he should have the smarts to be able to connect something better than Ember. Sometimes they call in a sparks for this, but in the end it is the same wiring than a conventional manual system, or less as the stats can be wireless.
The Drayton Nest and and other Smart stats can connect wirelessly back to their controller, so a single controller or combined controllers (depending on brand) are used to call the boiler and open the zone valves, same as the ember or manual controllers. Make sure to get TRV valve bodies on your rads if not already there, you'll need these to put smart TRV heads (or even manual heads) on. The real trick with smart TRV equipped systems is that a smart TRV, when it opens to heat a room, will call the boiler to supply the necessary heated water through the associated controller. manual TRVs just limit a room temperature, but can't initiate a heating call by themselves.
If you only get TRV valve bodies on the rads, with or without manual TRV 'knobs', you can easily install the Smart TRVs later yourself. Drayton smart TRVs are currently only £39.99 on Amazon, So you could squirrel away a half dozen of these for £240, about €280, pop them on at your leisure and add them to the original Drayton Wiser Kit 2 or 3 app. I doubt if you'd get much change from a grand if you asked for the installation of six smart TRVs in addition to your existing upgrade quote, so this way will save you a buck, but I could be wrong.

He suggested the Bosch SmartControl. It looks good to me; has the main features we're interested in. Is it considered a good choice?

https://www.worcester-bosch.co.uk/products/boiler-controls/bosch-easycontrol.

Been impressed with his knowledge and pricing tbh. Also need TRVs on at least half the radiators to avail of grant.

deezell

Penny Huge Clock wrote: »

He suggested the Bosch SmartControl. It looks good to me; has the main features we're interested in. Is it considered a good choice?

https://www.worcester-bosch.co.uk/products/boiler-controls/bosch-easycontrol.

Been impressed with his knowledge and pricing tbh. Also need TRVs on at least half the radiators to avail of grant.

I came across this before, just refreshed my memory with a speed read of the installation etc. Aside from the programming, scheduling and geo-locations features (Away mode), which would be broadly similar, there are a number of issues which must be decided at the outset to make this optimal

1. Are you installing a new Bosch boiler with bosch EMS Bus connection?
If using any other make you will need an adapter (~€50) to connect via SL (switched live) or OT (OpenTherm)

2 Will you be taking HW direct from the boiler, or do you have/will you still have a HW cylinder?
The Stat has no facility to control a HW valve on a zoned system with a cylinder, just direct HW from a Bosch or an OT compatible boiler with the mentioned adaptor.
3. Did you desire general zones aside from TRV'd individual rooms? have you already got this?
The stat is a single wired room stat, giving you only one general zone, which on its own is not grant compliant. It does not seem to accommodate an additional wall stat for say, upstairs. Without the adaptor it can't switch zone valves, though the matching Bosch Boiler may have an output for this.4.

4. This is the most concerning bit

Quote from their FAQs, "Currently the system has been designed with the assumption that Smart TRV’s are installed on every radiator, if there is no Smart TRV installed in the same zone as the EasyControl then heating will not be triggered. If you are experiencing this issue, then you must install or move a Smart TRV into the same zone as the EasyControl."
This implies that as soon as you connect a single TRV, only TRVs will call the boiler, the stat itself will not call the boiler based on the temperature of its location. It now just acts as a controller. You must install at least one TRV in that location, and a number of others to get a resemblance to zones. If your system is/is about to be plumbed single zone, Then all non smart TRV radiator will heat for any call from a TRV. This is also true for other brands, but the main stat will still call the boiler for the zone in general, while TRV stats are free to close and open according to their own demands. It means you must really equip most all radiators with TRVs, as you have no distinct plumbed zones
In short, this system provides either a single zoned heating control via the stat, or a zoned system via TRVs, and HW control is only available with direct HW boilers. If you're happy with this, then it's your choice. It can be costly to separate you home int plumbed zones if not already done, TRVs are a reasonable solution to zoning, while with other brands a main stat can still be used for general control of the non TRVd stats and areas, but not apparently with the Bosch. It will be cost effective as there is no additional plumbing required other than the installaion of the system, TRV valve bodies if not on the rads already, and Bosch or OT boiler to get direct HW.

s7ryf3925pivug

deezell wrote: »

I came across this before, just refreshed my memory with a speed read of the installation etc. Aside from the programming, scheduling and geo-locations features (Away mode), which would be broadly similar, there are a number of issues which must be decided at the outset to make this optimal

1. Are you installing a new Bosch boiler with bosch EMS Bus connection?
If using any other make you will need an adapter (~€50) to connect via SL (switched live) or OT (OpenTherm)

2 Will you be taking HW direct from the boiler, or do you have/will you still have a HW cylinder?
The Stat has no facility to control a HW valve on a zoned system with a cylinder, just direct HW from a Bosch or an OT compatible boiler with the mentioned adaptor.
3. Did you desire general zones aside from TRV'd individual rooms? have you already got this?
The stat is a single wired room stat, giving you only one general zone, which on its own is not grant compliant. It does not seem to accommodate an additional wall stat for say, upstairs. Without the adaptor it can't switch zone valves, though the matching Bosch Boiler may have an output for this.4.

4. This is the most concerning bit

Quote from their FAQs, "Currently the system has been designed with the assumption that Smart TRV’s are installed on every radiator, if there is no Smart TRV installed in the same zone as the EasyControl then heating will not be triggered. If you are experiencing this issue, then you must install or move a Smart TRV into the same zone as the EasyControl."
This implies that as soon as you connect a single TRV, only TRVs will call the boiler, the stat itself will not call the boiler based on the temperature of its location. It now just acts as a controller. You must install at least one TRV in that location, and a number of others to get a resemblance to zones. If your system is/is about to be plumbed single zone, Then all non smart TRV radiator will heat for any call from a TRV. This is also true for other brands, but the main stat will still call the boiler for the zone in general, while TRV stats are free to close and open according to their own demands. It means you must really equip most all radiators with TRVs, as you have no distinct plumbed zones
In short, this system provides either a single zoned heating control via the stat, or a zoned system via TRVs, and HW control is only available with direct HW boilers. If you're happy with this, then it's your choice. It can be costly to separate you home int plumbed zones if not already done, TRVs are a reasonable solution to zoning, while with other brands a main stat can still be used for general control of the non TRVd stats and areas, but not apparently with the Bosch. It will be cost effective as there is no additional plumbing required other than the installaion of the system, TRV valve bodies if not on the rads already, and Bosch or OT boiler to get direct HW.

Thanks that's a great reply.

Yes to 1 and 2 - getting a new Bosch combi boiler.

3. Currently only have HW and CH zoning. I think he mentioned implementing zoning to comply with grant requirement.

4. We'd be getting a TRV in the same room as the thermostat. We were not planning every room because as I understand it boxing off radiator and curtains hanging on the TRVs interfere with their thermostats. We might think a but more about what we do in this regard.

deezell

Penny Huge Clock wrote: »

Thanks that's a great reply.

Yes to 1 and 2 - getting a new Bosch combi boiler.

3. Currently only have HW and CH zoning. I think he mentioned implementing zoning to comply with grant requirement.

4. We'd be getting a TRV in the same room as the thermostat. We were not planning every room because as I understand it boxing off radiator and curtains hanging on the TRVs interfere with their thermostats. We might think a but more about what we do in this regard.

With Tado you can assign a wall stat as the measuring device for a TRV or a group of them in a zone. This eliminates the rad box/ curtain issue. You can also calibrate Tado TRVs with an offset to compensate for under/over reporting of room temperature.

Ethereal Cereal

Hey

My current heating setup is a standard boiler in the utility room that I control by going out to the utility room and turning the switch on the boiler on or off

Can I use the tado (or similar) Smart Radiator Thermostat without any boiler wiring or upgrade? Like can I set the specific radiator to a certain temp, and when the room reaches that temp, it will just turn off the heat? I would install a couple of these smart Rad thermostats around the house.


https://www.tado.com/ie/products/smart-radiator-starter-kit

thanks in advance!

garo

deezell wrote: »

A quick look at the installation guide for this boiler and the plus shows identical wiring diagrams, with an OT terminal, ( page 31), typical S or Y plan layout, and significantly, suggested interconnection to an Evohome, (page 33), which shows as I predicted, the valves connected via both BDR91 relays, but also the OT terminal on the boiler connected to the OT receiver bridge. In this arrangement, as I previously stated, the valves' own relays are not used to send SL to the boiler, for either HW or CH, as this is done by the OT connection. Study pages 31-33.
https://idealboilers.com/uploads/documents/Logic_System_Installation_Servicing.pdf
Just make certain this is the boiler you are getting.

Sorry for the late reply. I got two other quotes, one from an SEAI approved installer and the other from my plumber and his electrician. The Electric Ireland deal seems to be the cheapest for the setup I want.

Back on the OpenTgerm question I found this quote from someone on the automatedhome U.K. Forum which seems to be the way forward. The system is set up HE priority with OT only controlling the firing when CH calls for heat. The HW firing is not modulated by OT and seems to be at the highest temp always.

I live in a 5 bed/19 radiator house which is divided into 12 zones. All the radiators have HR92s fitted to them. The boiler (an ATag is24) is protected by an automatic bypass valve. HW temperature control is via the Evohome HW kit connected in series with the unvented stat in the HW cylinder and controlled by a single BDR91. CH is via the Evohome controller connected to the boiler via an Opentherm Bridge. The system is configured for HW priority. The boiler parameters are set to a maximum temperature profile of 70C (TMax Set).

deezell

Ethereal Cereal wrote: »

Hey

My current heating setup is a standard boiler in the utility room that I control by going out to the utility room and turning the switch on the boiler on or off

Can I use the tado (or similar) Smart Radiator Thermostat without any boiler wiring or upgrade? Like can I set the specific radiator to a certain temp, and when the room reaches that temp, it will just turn off the heat? I would install a couple of these smart Rad thermostats around the house.


https://www.tado.com/ie/products/smart-radiator-starter-kit

thanks in advance!

Tado requires at least one Tado thermostat to act as the relay switch for the boiler. The TRVs communicate with it, and it calls the boiler. It will of course call the boiler in its own right according to its temperature settings, Unless you designate one of the TRVs as the measuring device for the stat, in which case it becomes just a relay.

Ethereal Cereal

deezell wrote: »

Tado requires at least one Tado thermostat to act as the relay switch for the boiler. The TRVs communicate with it, and it calls the boiler. It will of course call the boiler in its own right according to its temperature settings, Unless you designate one of the TRVs as the measuring device for the stat, in which case it becomes just a relay.

Thanks, I would probably need to set a TRV as a measuring device then. My boiler is in the utility room, where its much more colder than than in the house.

deezell

garo wrote: »

Sorry for the late reply. I got two other quotes, one from an SEAI approved installer and the other from my plumber and his electrician. The Electric Ireland deal seems to be the cheapest for the setup I want.

Back on the OpenTgerm question I found this quote from someone on the automatedhome U.K. Forum which seems to be the way forward. The system is set up HE priority with OT only controlling the firing when CH calls for heat. The HW firing is not modulated by OT and seems to be at the highest temp always.

HW is not modulated by OT, but the boiler is still called by the OT cable connection, it would be unlikely that the boiler could be called via it's SL terminals if it is under control by OT. The difference is that unlike a SL call, with an OT call the boiler knows it is require for HW, CH, or both. For CH it midulates, and uses lower temperatures for efficiency. For HW it heats to beyond the temperature setting of the wireless stat, so heat transfer can take place. HW priority means it will cease CH until HW is satisfied, then return to modulated CH.

deezell

Also in relation to this installation,

......The boiler (an ATag is24) is protected by an automatic bypass valve. HW temperature control is via the Evohome HW kit connected in series with the unvented stat in the HW cylinder and controlled by a single BDR91. CH is via the Evohome controller connected to the boiler via an Opentherm Bridge. The system is configured for HW priority. The boiler parameters are set to a maximum temperature profile of 70C (TMax Set).

It is not immediately clear if the BDR91 relay is used to open the HW valve (s plan) or a diverter valve (y plan), but as it is wired HW priority, either is achievable. While the BDR91 will open the HW valve, priority or otherwise, it's more than likely the boiler call itself is achieved via the Evohome OT connection to the boiler. Furthermore, this boiler in itself has HW priority signalling available to control a diverter valve, acting in response to a directly connected cylinder stat sensor to the boiler. In this instance the boilers own electronics reads the sensor, and opens the diverter valve in HW priority mode at the higher unmodulated temperature. This control should be available to the Evohome via OT, but I can only speculate as to why it was necessary to drive the HW relay via an Evohome BDR91, unless the system is an S plan with individual HW and CH relays. It's moot, as you are using a boiler different to the ATag is24.

deezell

Ethereal Cereal wrote: »

Thanks, I would probably need to set a TRV as a measuring device then. My boiler is in the utility room, where its much more colder than than in the house.

If you can run a pair of wires to a central location of the house, hall or living room, you can have the main stat as the general controller of temperature, and have the 2 TRVs as independent zones, closing off when not required while the main stat will continue to act on behalf of the remaining non TRV rads. Main stat is accurate to 0.1°, whereas TRVs are set in 1° steps.

garo

deezell wrote: »

Also in relation to this installation,

It is not immediately clear if the BDR91 relay is used to open the HW valve (s plan) or a diverter valve (y plan), but as it is wired HW priority, either is achievable. While the BDR91 will open the HW valve, priority or otherwise, it's more than likely the boiler call itself is achieved via the Evohome OT connection to the boiler. Furthermore, this boiler in itself has HW priority signalling available to control a diverter valve, acting in response to a directly connected cylinder stat sensor to the boiler. In this instance the boilers own electronics reads the sensor, and opens the diverter valve in HW priority mode at the higher unmodulated temperature. This control should be available to the Evohome via OT, but I can only speculate as to why it was necessary to drive the HW relay via an Evohome BDR91, unless the system is an S plan with individual HW and CH relays. It's moot, as you are using a boiler different to the ATag is24.

Thanks. So I called up EI to get more details on what they intend to do in my house. There are not planning an S or Y plan layout as we traditionally understand but in effect it is close to the S plan without requiring any pipe work. Basically they are installing a motorised valve on the HW pipe and letting the Smart TRVs control the CH. So CH is essentially always open regardless of what calls for heat. But when the HW sensor calls for heat and none of the Smart TRVs are open they don't get any circulating heat. There will be some convection loss onto the pipes leading to the rads but assume that is not major.
When cylinder is at required temp and a rad needs heat, the boiler fires and the valve to the cylinder is closed so only CH is on.
Unfortunately EI are not doing OpenTherm so I will have to do it afterwards. I assume in this setup it would be possible?

john_doe.

Hi

Have added a sonoff temperature sensor to tank to measure hot water temp.

We have in the summer, solar to heat the hot water. On cloudy days I often use the oil burner to heat the hot water also.

There is however an immersion control on tank and a manual switch I have never used.

I was wondering do systems like Tado allow u to heat water from different sources such as immersion and oil burner.

I.e let's say in summer I wanted to use either the oil burner or the immersion to heat the water, how does this work?

deezell

john_doe. wrote: »

Hi

Have added a sonoff temperature sensor to tank to measure hot water temp.

We have in the summer, solar to heat the hot water. On cloudy days I often use the oil burner to heat the hot water also.

There is however an immersion control on tank and a manual switch I have never used.

I was wondering do systems like Tado allow u to heat water from different sources such as immersion and oil burner.

I.e let's say in summer I wanted to use either the oil burner or the immersion to heat the water, how does this work?

Tado at most can control timing of HW in a cylinder, with temperature controlled by a manual stat, or in your case a Sonoff.
When you have Solar heating you will have to decide at what point oil or immersion heating is brought into play. Normally you will revert HW control back to either source when it is obvious that solar will not contribute, such as after darkness. What you are trying to avoid on the one hand is insufficient HW before the timed oil/immersion cuts in. Conversely, if you allow these to heat the cylinder early in the day, you may end up with excess solar heated water which has to be released to avoid overheating of the cylinder. The position of the thermostat on the tank can be used to create a layer of sufficientlu heated water on the top of the tank, with the solar being used to pre heat the water from the bottom up, which may prevent the solar from heating the water sufficiently hot for normal requirements but will at least have preheated most of the water in the cylinder so that the oil/ immersion can bring it up to working temperature. On a bright sunny day the solar will be capable of heating the entire cylinder to working temperature, so it's a question if how long you wish to give the solar exclusive heating of the cylinder before you use the oil/immersion to bring the top of the cylinder up to heat
This conundrum can be minimised by the use of a special cylinder known as a fenestrated coil. In this cylinder the extremely hot solar fluid is not fed directly in the base coil of the cylinder, where it will cool quickly as it tries to heat the entire cylinder because of convection, which is the normal scenario. Instead the fluid is directed into an enclosed heat exchanger internal or external to the cylinder body. The fluid is in contact with only a small amount of the cylinder water, and this heats rapidly and up to working temperature, whence it moves by convection to the top of the cylinder and sits over the cooler water. This allows solar to provide working temperature water quickly even on dull days, and reduce the incidence of timed oil/immersion use.
Finally, how you decide to heat, oil or immersion, is not something you can specifically automate, other than to have the different sources on timers. You can have another sonoff to direct the thermostat call for heat to either the oil boiler, or to a mains operated high current relay to supply the immersion. The Sonoff itself is not ideal for providing the high current used by an immersion element. You need to work through the logic of your HW requirements, and draw up an IF THEN list of steps for what you wish to hapoen depending on time of day, temperature of the working HW, temperature of the solar fluid, and whether you want to supplement heating by oil or immersion. Plenty of potential for confùsion, and possibly unexpected results if stat settings result in a heating call which then prevents other heat sources from ever being invoked.

john_doe.

deezell wrote: »

Tado at most can control timing of HW in a cylinder, with temperature controlled by a manual stat, or in your case a Sonoff.
When you have Solar heating you will have to decide at what point oil or immersion heating is brought into play. Normally you will revert HW control back to either source when it is obvious that solar will not contribute, such as after darkness. What you are trying to avoid on the one hand is insufficient HW before the timed oil/immersion cuts in. Conversely, if you allow these to heat the cylinder early in the day, you may end up with excess solar heated water which has to be released to avoid overheating of the cylinder. The position of the thermostat on the tank can be used to create a layer of sufficientlu heated water on the top of the tank, with the solar being used to pre heat the water from the bottom up, which may prevent the solar from heating the water sufficiently hot for normal requirements but will at least have preheated most of the water in the cylinder so that the oil/ immersion can bring it up to working temperature. On a bright sunny day the solar will be capable of heating the entire cylinder to working temperature, so it's a question if how long you wish to give the solar exclusive heating of the cylinder before you use the oil/immersion to bring the top of the cylinder up to heat
This conundrum can be minimised by the use of a special cylinder known as a fenestrated coil. In this cylinder the extremely hot solar fluid is not fed directly in the base coil of the cylinder, where it will cool quickly as it tries to heat the entire cylinder because of convection, which is the normal scenario. Instead the fluid is directed into an enclosed heat exchanger internal or external to the cylinder body. The fluid is in contact with only a small amount of the cylinder water, and this heats rapidly and up to working temperature, whence it moves by convection to the top of the cylinder and sits over the cooler water. This allows solar to provide working temperature water quickly even on dull days, and reduce the incidence of timed oil/immersion use.
Finally, how you decide to heat, oil or immersion, is not something you can specifically automate, other than to have the different sources on timers. You can have another sonoff to direct the thermostat call for heat to either the oil boiler, or to a mains operated high current relay to supply the immersion. The Sonoff itself is not ideal for providing the high current used by an immersion element. You need to work through the logic of your HW requirements, and draw up an IF THEN list of steps for what you wish to hapoen depending on time of day, temperature of the working HW, temperature of the solar fluid, and whether you want to supplement heating by oil or immersion. Plenty of potential for confùsion, and possibly unexpected results if stat settings result in a heating call which then prevents other heat sources from ever being invoked.

Thanks for the detailed response.
Let's say i wasn't trying to automate it, more remote control.

Currently I manually switch the oil boiler on for half an hour to provide hot water , if solar wasnt effective.

The Tado effectively so just adds a timer to fire the boiler albeit a smart timer and has nothing to do with the immersion . I think the ember drives to temperature but maybe not

Let's say I added Tado, this would give me timer control to fire the boiler on when I wanted based on schedule.

To control the immersion I could add another sonoff with contactor as you mentioned or one of those fused spur wifi sockets. That itself would be completely separate.

What I'm thinking is how I use system to date , if I see hot water is low temp or I need it for morning I set it to come on in morning for half an hour via oil - the Tado would prob allow me to do this from my phone instead of the manual analog clock I have to date I guess ?

If I decided to use the immersion to top up hot water I'd use the sonoff or the wifi socket.

Your post gives me a lot to think about however.

Using the immersion vs the oil I'd imagine is a complicated comparison depending on night rate , heat loss I'd imagine . I've been using oil to date to heat hot water in summer but after getting the sonoff I started to wonder should I be using the immersion instead and would it work out cheaper

deezell

One simple question. Why are you not using the relay in the sonoff which measures your HW temperature yo call the boiler for HW? You can set up a schedule on the sonoff app, have it come on and off in response to different times and temperature thresholds to suit the availability of solar at different times if the day. This is the whole purpose if a stat on the cylinder, to automate HW heating

john_doe.

deezell wrote: »

One simple question. Why are you not using the relay in the sonoff which measures your HW temperature yo call the boiler for HW? You can set up a schedule on the sonoff app, have it come on and off in response to different times and temperature thresholds to suit the availability of solar at different times if the day. This is the whole purpose if a stat on the cylinder, to automate HW heating

I did think along that line but not fully convinced on sonoff, maybe with a contactor or relay I'd use them. They slightly give a concern on electrical safety and network security.
I scaled the use of the sonoff back to just a temp measurement device, maybe the price just seems too good to be true on the sonoff 😀

I am looking at Drayton/Tado for the heating as well so I thought they could handle the boiler schedule for hot water as well.

The immersion had me perplexed though.
Not sure is it more efficient than using the boiler if I need hot water in summer or am I better off with using oil for that.

deezell

Electricity roughly twice the price per kWh for water heating. Sonoff perfectly safe for signalling a boiler/ pump/valves to commence heating, current requirement for this minimal. Immersion elements require currents at the outer limit of sonoff relays, so for safety it's best to use the Sonoff to trigger a standard installed mains din rail relay in an enclosure and power the immersion from this.

john_doe.

deezell wrote: »

Electricity roughly twice the price per kWh for water heating. Sonoff perfectly safe for signalling a boiler/ pump/valves to commence heating, current requirement for this minimal. Immersion elements require currents at the outer limit of sonoff relays, so for safety it's best to use the Sonoff to trigger a standard installed mains din rail relay in an enclosure and power the immersion from this.

Thanks

I might start by logging the temperature behavior from the boiler/solar, has anyone here passed the sonoff temps to SQL or other .
Looking at page below looks interesting.

https://discourse.nodered.org/t/managing-a-boiler-with-nodered-and-sonoff/1712

deezell

john_doe. wrote: »

Thanks

I might start by logging the temperature behavior from the boiler/solar, has anyone here passed the sonoff temps to SQL or other .
Looking at page below looks interesting.

https://discourse.nodered.org/t/managing-a-boiler-with-nodered-and-sonoff/1712

Serious anorak stuff. I think you should just use your sonoff thermostat's relay contacts to call the boiler and set up a daily HW schedule. There's little to be gained in savings by programming your HW temperature up and down. If your cylinder is deep insulated, losses are low, and the difference between keeping water at 45° and 60° will produce trivial savings, unless you are in the inefficient habit of washing hands/crockery under a flowing tap. If your cylinder is a bare copper type with a ubiquitous lagging jacket hanging off it, then the path to savings is to replace the cylinder. There's very little insulation u value in an SQL database.

s7ryf3925pivug

deezell wrote: »

With Tado you can assign a wall stat as the measuring device for a TRV or a group of them in a zone. This eliminates the rad box/ curtain issue. You can also calibrate Tado TRVs with an offset to compensate for under/over reporting of room temperature.

Actually, is there any need for the smart controller, or can I just use the Bosch smart TRVs with Philip's hue and alexa. I'll have a combi boiler so would turning on the radiator activate the central heating by itself? Or alternatively could I leave the central heating on but with all the trvs off, so it would not actually be heating but in a standby state?

I know there are extra features with the controller like tracking usage patterns and gas consumption, but they would not be worth the extra cost if we can set the individual room temperatures remotely.

We have 8 rads. Will be extending and adding a few more in a year.

edit: amazon q&a for the smart trvs indicates that they need the smart controller to function.

john_doe.

deezell wrote: »

Serious anorak stuff. I think you should just use your sonoff thermostat's relay contacts to call the boiler and set up a daily HW schedule. There's little to be gained in savings by programming your HW temperature up and down. If your cylinder is deep insulated, losses are low, and the difference between keeping water at 45° and 60° will produce trivial savings, unless you are in the inefficient habit of washing hands/crockery under a flowing tap. If your cylinder is a bare copper type with a ubiquitous lagging jacket hanging off it, then the path to savings is to replace the cylinder. There's very little insulation u value in an SQL database.

thanks, the sonoff that measures the temp of the tank is one location of the house, the analogue switch that fires the oil is in the opposite end. Cabling it is bit of pain.
I was looking at a way to link the two sonoffs together , i.e the TH16 just measures the temp of the water and passes the temp to an MQTT broker , when the temp is below 38 degress , it turns on the second sonoff and fires the boiler for an hour or untill it hits 60 degrees.

Not sure can sonoffs be grouped that way without flashing them.
From playing around with one i have you cant set them based on both time and temperature anyway, its one or the other.
Really i just wanted to get started with some stuff and was looking at this as a bit of a test case.

on a seperate note , there are 4 temp measure areas on hot water tank ,one is used by the stat, and 2 are used by solar. the other is free but is at bottom of the tank.

whats the logic with solar having two probes - is it to measure the differential in the tank. Also for the TH16 im guessing the best place to measure is near to top of the tank?

john_doe.

deezell wrote: »

Serious anorak stuff. I think you should just use your sonoff thermostat's relay contacts to call the boiler and set up a daily HW schedule. There's little to be gained in savings by programming your HW temperature up and down. If your cylinder is deep insulated, losses are low, and the difference between keeping water at 45° and 60° will produce trivial savings, unless you are in the inefficient habit of washing hands/crockery under a flowing tap. If your cylinder is a bare copper type with a ubiquitous lagging jacket hanging off it, then the path to savings is to replace the cylinder. There's very little insulation u value in an SQL database.

thanks, the sonoff that measures the temp of the tank is one location of the house, the analogue switch that fires the oil is in the opposite end. Cabling it is bit of pain.
I was looking at a way to link the two sonoffs together , i.e the TH16 just measures the temp of the water and passes the temp to an MQTT broker , when the temp is below 38 degress , it turns on the second sonoff and fires the boiler for an hour or untill it hits 60 degrees.

Not sure can sonoffs be grouped that way without flashing them.
From playing around with one i have you cant set them based on both time and temperature anyway, its one or the other.
Really i just wanted to get started with some stuff and was looking at this as a bit of a test case.

on a seperate note , there are 4 temp measure areas on hot water tank ,one is used by the stat, and 2 are used by solar. the other is free but is at bottom of the tank.

whats the logic with solar having two probes - is it to measure the differential in the tank. Also for the TH16 im guessing the best place to measure is near to top of the tank?

deezell

Solar controllers measures the difference in cylinder water (at the solar coil), and solar panel fluid, and pumps the fluid if there is a difference of more than 5°. The water at the top of the tank may be hotter than the solar fluid but heating the bottom layer of water reduces the amount of heat required from oil or gas to bring it up to temperature. In very sunny weather there is the chance that the top of the tank will heat way beyond required temperature. While a mixer valve will prevent scalding when using the hot water, the solar controller needs a means to stop heating the cylinder after a set point. To this end a third stat is required, a limit stat on the cylinder, which can be used to stop the solar fluid pump circulation through the cylinder, and also to open a valve to waste some of the overheated water.

garo

Thought I would post an update. Had the Evohome installed last week. Loving the fine-grained control. Do I need it? No. But do I want it. Heck yeah.

Also interesting to note that this is the first time my HW is being heated independently of CH and it is amazing to note how quickly a 117l cylinder gets used up. Must have been heating a lot of water but never noticed.

deezell

garo wrote: »

Thought I would post an update. Had the Evohome installed last week. Loving the fine-grained control. Do I need it? No. But do I want it. Heck yeah.

Also interesting to note that this is the first time my HW is being heated independently of CH and it is amazing to note how quickly a 117l cylinder gets used up. Must have been heating a lot of water but never noticed.

That's a small enough cylinder. A couple of showers would use 150l, say about half that from the hot, so you'd be down to the lukewarm water in the bottom third of the cylinder very quickly. The only way to save on hot water is cold showers or BO! Just set the timer on at all times during the day.

garo

Yes that is similar to what I have done. Set the hot water to come on for intervals ranging from 10 mins to an hour 3 times a day. It is temperature controlled so boiler would turn off when cylinder reaches required temp. Seems to be working fine. I replaced my old lagging insulated copper cylinder with a factory insulated one last year so am loathe to change now but in retrospect should have gone for a larger one. It required at a bit of carpentry work in the hot press so I passed at the time. Now regretting it especially since I am getting a solar PV system and would use a hot water diverter to capture the excess.
As an aside the boiler wasn't changed as the installer - surprisingly said the old boiler was good enough and a bit of tuning got the efficiency up from 68% to 84%. Unexpected bonus and a thorough gentleman. PM me if anyone wants his name. He does gas/plumbing/electrical wiring around heating systems.
So I have the old boiler still and the OpenTherm becomes irrelevant.

deezell

Unless you want to install a second small tank and use it as a pre heat store. Solar PV would not generate a huge amount of heated water compared to the same panel area of solar water heating panels, ten PV panels would produce about 2.5 kW in optimal conditions, which is a moderate kettle element. This could be connected to your cylinder immersion, or to a parallel or series additional tank.