Home heating automation

deezell · 15-07-2020 10:54am

Should have also said the MoesGo is a wired stat, no receiver, just divert the existing timer wiring to it.

Toots · 15-07-2020 11:04am

It's the potentially crappy app that's putting me off that, but I suppose with the price it might be worth trying. I think the likes of the Hive/Tado have good straightforward apps which would be important for my parents. I have some of those chinese smart plugs and while they work well, the app is not very user friendly.

I'll get the husband to have a look at what way the boiler is set up - I've just had a look under the stairs and the heating is running right now and only the little radiator symbol is showing on the display. They've never touched the mode button on it, it's how the installers set it up when they put it in about 2 years ago.

john_doe. · 15-07-2020 11:11am

"it makes no sense whatsoever, but I'm sure it will work for you"

the logic is basically a reproduction of what the Lex box is doing. The Lex box that is there currently needs to be replaced as it is faulty so it was either a case of buying another or the PLC.

. Me, I would just have installed the Wiser receiver ( it is the Wiser 3 channel receiver/hub?)

Yes its a 3 channel

I'd worry with full trv control that you haven't left some open rads (other than towel rails) to absorb stove heat.

there is also no smart TRV on Radiator 14.

your diagrams have multiple stove stat NO connections, but these all seem to be the same pair? It's not clear what anything does.

the stove stat connections are just logical and not physical i.e there is only one stove stat input but its referenced by the logic in a few places.
the Logo logic diagrams are a bit confusing the way they lay them out , i have added comments to the attached which hopefully clears it up?

ignore the manual switches if needed , they are only there for a backup if the drayton fails and i need to turn on the system by flipping them. There are two manual physical overrides. I2 (heating manual). I3(hot water manual). they would only be activated in situation where the drayton goes down- ive heard there have been couple of reported instances a year of this, so wanted to have a way of turning on system if drayton stopped working. I1 (automation on) is another manual switch , that is always switched on- it probably serves no purpose really and could be removed.

The bit about the boiler having no SL, I presume it's a basic mains controlled boiler, on or off, no permanent live for digital circuits or temperature displays or post purge or any of that modern pansy stuff. (I'm joking).

exactly

The only issue wirh this boiler might be the current requirement via the contacts of the lex box relay, as it's powering the entire boiler which has a decent inductive start up surge. Still, lex box or it's replacement should be up to it, just check the boiler mains rating and the relays rating thats firing the boiler.

Good point. Thanks

I think I've commented on all this before in this thread?

you have , thanks for that , but i put it on the long finger till now as couldnt get a plumber or electrician.

Again, I assume you have the Drayton Wiser controller, you mention of manual stats is at odds with the smart TRVs which require the wiser channel hub to fire the boiler. Perhaps you're not using the main stats at all? Keep at it and good luck.

Yes i have the Drayton, the manual timers will be removed. i also have the drayton smart room stats though in some rooms, they are little square boxes that allow you to get a better temperature reading than at the TRV. For example in kitchen i have two radiators , the drayton stat groups them together as a logic "kitchen" stat that makes the call.

https://wiser.draytoncontrols.co.uk/smart-room-thermostat

fitzparker · 15-07-2020 5:51pm

Would anyone know of the Netatamo controls heating and hot water separate?

Enerigia are offering it.

We don't use hot water (have power shower ) so would like it to control the heating only and not turn on the hot water.

Thanks

deezell · 15-07-2020 7:00pm

fitzparker wrote: »

Would anyone know of the Netatamo controls heating and hot water separate?

Enerigia are offering it.

We don't use hot water (have power shower ) so would like it to control the heating only and not turn on the hot water.

Thanks

Netatmo is a CH smart thermostat only. They have no HW timer function. If you have direct boiler HW system, or if you have a HW cylinder but don't heat it with your boiler, or if you don't require remote timing option of your HW, then Netatmo is fine. It can be a wired unit or wireless, so it can be directly wired in place of an existing mechanical thermostat. If you have no thermostat, just a boiler or zone timer, you can install the wireless Netatmo in the main zone area, with it's wireless receiver connected to the boiler, or zone valve if you have more than one zone.

fitzparker · 16-07-2020 10:50am

deezell wrote: »

Netatmo is a CH smart thermostat only. They have no HW timer function. If you have direct boiler HW system, or if you have a HW cylinder but don't heat it with your boiler, or if you don't require remote timing option of your HW, then Netatmo is fine. It can be a wired unit or wireless, so it can be directly wired in place of an existing mechanical thermostat. If you have no thermostat, just a boiler or zone timer, you can install the wireless Netatmo in the main zone area, with it's wireless receiver connected to the boiler, or zone valve if you have more than one zone.

Perfect, SOunds like it would work for us.

Im not sure what I have, just a controls has one button for CH and one for HW (we very rarely turn the HW one on) then just the one thermostat controlling the whole house at one temp ( not multi zone)

deezell · 16-07-2020 10:55am

fitzparker wrote: »

Perfect, SOunds like it would work for us.

Im not sure what I have, just a controls has one button for CH and one for HW (we very rarely turn the HW one on) then just the one thermostat controlling the whole house at one temp ( not multi zone)

A wired Netatmo or Tado is ideal for this. Just swap out the stat. Leave your controller with CH on all the time, the smart stat will fully control timing and temperature.

john_doe. · 19-07-2020 4:15pm

john_doe. wrote: »

"it makes no sense whatsoever, but I'm sure it will work for you"

the logic is basically a reproduction of what the Lex box is doing. The Lex box that is there currently needs to be replaced as it is faulty so it was either a case of buying another or the PLC.

. Me, I would just have installed the Wiser receiver ( it is the Wiser 3 channel receiver/hub?)

Yes its a 3 channel

I'd worry with full trv control that you haven't left some open rads (other than towel rails) to absorb stove heat.

there is also no smart TRV on Radiator 14.

your diagrams have multiple stove stat NO connections, but these all seem to be the same pair? It's not clear what anything does.

the stove stat connections are just logical and not physical i.e there is only one stove stat input but its referenced by the logic in a few places.
the Logo logic diagrams are a bit confusing the way they lay them out , i have added comments to the attached which hopefully clears it up?

ignore the manual switches if needed , they are only there for a backup if the drayton fails and i need to turn on the system by flipping them. There are two manual physical overrides. I2 (heating manual). I3(hot water manual). they would only be activated in situation where the drayton goes down- ive heard there have been couple of reported instances a year of this, so wanted to have a way of turning on system if drayton stopped working. I1 (automation on) is another manual switch , that is always switched on- it probably serves no purpose really and could be removed.

The bit about the boiler having no SL, I presume it's a basic mains controlled boiler, on or off, no permanent live for digital circuits or temperature displays or post purge or any of that modern pansy stuff. (I'm joking).

exactly

The only issue wirh this boiler might be the current requirement via the contacts of the lex box relay, as it's powering the entire boiler which has a decent inductive start up surge. Still, lex box or it's replacement should be up to it, just check the boiler mains rating and the relays rating thats firing the boiler.

Good point. Thanks

I think I've commented on all this before in this thread?

you have , thanks for that , but i put it on the long finger till now as couldnt get a plumber or electrician.

Again, I assume you have the Drayton Wiser controller, you mention of manual stats is at odds with the smart TRVs which require the wiser channel hub to fire the boiler. Perhaps you're not using the main stats at all? Keep at it and good luck.

Yes i have the Drayton, the manual timers will be removed. i also have the drayton smart room stats though in some rooms, they are little square boxes that allow you to get a better temperature reading than at the TRV. For example in kitchen i have two radiators , the drayton stat groups them together as a logic "kitchen" stat that makes the call.

https://wiser.draytoncontrols.co.uk/smart-room-thermostat

Traced the existing wires yesterday.
The PLC logic works (in simulation anyway)
Hopefully the logic makes sense from plumbing perspective.

garo · 19-07-2020 5:44pm

I have a question about pump overrun after the boiler shuts down. I have an old “dumb” boiler Ideal Classic FF18 - 15 years old 84% efficient but works well. I have an Evohome system to control CH and HW and a Grundfos pump. There is a zone valve for hot water and TRVs on every radiator. I don’t know if there is a bypass.

So the pump shuts down as soon as the boiler goes off - I assume they are wired together. This means that the boiler can often be quite hot for a while. I would like to have the pump overrun for a bit to take the latent heat out. Is there a way to do this while also making sure the pump is not running when the HW valve and all the TRVs are closed?

deezell · 19-07-2020 7:59pm

garo wrote: »

I have a question about pump overrun after the boiler shuts down. I have an old “dumb” boiler Ideal Classic FF18 - 15 years old 84% efficient but works well. I have an Evohome system to control CH and HW and a Grundfos pump. There is a zone valve for hot water and TRVs on every radiator. I don’t know if there is a bypass.

So the pump shuts down as soon as the boiler goes off - I assume they are wired together. This means that the boiler can often be quite hot for a while. I would like to have the pump overrun for a bit to take the latent heat out. Is there a way to do this while also making sure the pump is not running when the HW valve and all the TRVs are closed?

This will do the trick.
https://ie.rs-online.com/web/p/timer-relays/8966810/

garo · 20-07-2020 12:09am

Thanks. Apologies for the next question. How do I wire it? I found some vague instructions on automatedhome but also caution on not to use this if you don't have a bypass loop as the pump will be pushing against closed valves and that might damage the pump.

deezell · 20-07-2020 1:20am

garo wrote: »

Thanks. Apologies for the next question. How do I wire it? I found some vague instructions on automatedhome but also caution on not to use this if you don't have a bypass loop as the pump will be pushing against closed valves and that might damage the pump.

That is a minor issue, circulation pumps are inertia vane type, like a fan, it doesn't build up much pressure in static flow. When the flow is totally closed, all TRVs closed and HW valve closed, then there is no path alright. Your system probably could do with a bypass loop, or an open radiator to act as the same, such as a towel rail, especially one thats on a gravity path from the boiler with the pump off. This would give some relief to the residual hot water in the boiler jacket. If you have the boiler stat set to regulate the boiler to say 65°, when it cuts there's unlikely to be enough residual heat in the jacket baffles to boil it too 100°. A timer on the pump is only of use if there's an open path for pumped or gravity flow, so running the pump is not going to solve this problem which probably doesn't exist. Try turning down the general boiler flow temperature, no need to have it scalding, unless you have rooms that need the radiators 'hopping" to heat, but that would be a radiator size or room insulation problem. Your boiler will be more efficient if it's run a few degrees cooler, return water will be cooler and heat transfer higher.

There's a complicated wiring diagram for the relay on the site, but basically it's a mains triggered relay with a double pole single contact switch, which you would supply with permanent live in and connect the pump live to the relay live out, which is a mirror of the boiler live trigger plus an adjustable delay.

garo · 20-07-2020 5:32pm

Thanks. So I had the thermostat knob at a bit over 5 which is 77C according to this document. I have since turned it down to 3 which is 66C.
The document recommends a lower setting for the summer when only HW is needed anyway. Thanks for the prompt deezell. Hope this will resolve the issue and I won't need to worry about the pump overrun. Thanks for the wiring explanation as well. But I expect I won't need it now as the solution you suggest is much simpler.

garo · 21-07-2020 12:14am

So I dug into this a bit more and posting it here in case it helps someone else. The Evohome has a "Hot Water Overrun" feature that allows the hot water valve to stay open for a set time. So if you have a boiler that has a pump overrun or put in a delay timer on the pump AND you have a system where there is a valve to the HW, you can set the overrun timer on the evohome and it will leave the hot water valve open for that amount of time after the boiler has stopped firing. I checked today and it works. After the boiler stops, the hot water valve closes after the specified delay.

I may yet go for that delay timer switch deezell.

deezell · 21-07-2020 8:03am

garo wrote: »

So I dug into this a bit more and posting it here in case it helps someone else. The Evohome has a "Hot Water Overrun" feature that allows the hot water valve to stay open for a set time. So if you have a boiler that has a pump overrun or put in a delay timer on the pump AND you have a system where there is a valve to the HW, you can set the overrun timer on the evohome and it will leave the hot water valve open for that amount of time after the boiler has stopped firing. I checked today and it works. After the boiler stops, the hot water valve closes after the specified delay.

I may yet go for that delay timer switch deezell.

I had been reading a blog about Evohome to find more information about this. There were lots of references to percentage cycling and the like for CH, and complaints about residual cycling, where the Evohome would give the boiler one extra blast after its calling stat had reached set point. The basis of the complaints were that in these cases the room temperature would rise a further few degrees above setpoint, and posters found their system hysteresis too great, plus or minus 2-3°, which caused too hot/ too cold heating pattern. There was no solution offered in the blog, but it got me thinking that perhaps this was caused by a boiler overrun, but effective only if the rad TRVs / CH zone valve were shut and there was an open sink such as a towel rail or an open HW valve. If the posters had just an open rad system without smart TRVs and no CH zone valve of course the rads would heat in this instance. This problem may also have been to do with the Opentherm controlled boilers used by the posters.

Your boiler is a hard on/off job, but it has only a very small boiler surface as it is a gas boiler, with a small volume heat exchanger, so not a lot of residual heat in there to dissapate. The question now is how does the boiler fire for a HW only request from the evohome?
Is your HW demand to the boiler directly from the Evohome relay, the same one that calls the boiler for CH? Such a call would facilitate HW only if the system was full TRV, so that CH flow is cut while HW valve is opened. The evohome relay has a seperate HW On Switched Live terminal, this is what is connected to the HW valve to open it.
Normally, the HW valves's own aux relay is used to fire the boiler, ensuring the boiler doesn't fire for HW until the valve is opened, as a safety feature, and ensuring that a SL from a HW terminal doesn't cause the rads to heat by reverse opening a CH zone valve. (This would occur if the CH and HW SLs were just combined at the boiler.) This of course means that any call to the HW valve, including an overrun, would open the valve, close the relay and fire the boiler, so the overrun in this case would be pointless, nothing more than a short HW timing cycle.
So it depends on how your Evohome was wired. If the HW valve is passively opened by the evohome HW relay terminal , but the SL to the boiler is a common one for both CH and HW, then this overrun feature could be used to open the HW valve without boiler firing, leaving just the little matter of getting the circulation pump only to spin during this time.
If the above wiring scheme is true, and IF the HW zone valve has an unused boiler call relay, and IF this relay is a two pole relay with NO ( grey wire) and NC ( white wire) terminals, this relay could be used to control the SL source to the pump. By diverting the boiler SL to the pump via the valve NC terminal, and splitting the HW valve SL call ( brown wire) across to the NO terminal, then connecting the pump to the Common (orange wire) terminal, the pump will always circulate for a HW call or a CH/HW boiler call, but the boiler will only fire when the boiler call is on.
This solution will work if the HW valve is Not used to fire the boiler, and if it has an unused relay with the NC white wire terminal, many just have the grey and orange wires.
There's a bit to chew on there, so start examining how your Evohome boiler calls are made, for CH and HW.
Here's a typical 2 port valve wiring with NC terminal

images?q=tbn:ANd9GcTJnlfn3LmbqJ4pWfOvREUmxkxgM88YAWZ-nkrJqJJeuQ&s

images?q=tbn:ANd9GcTJnlfn3LmbqJ4pWfOvREUmxkxgM88YAWZ-nkrJqJJeuQ&s

garo · 21-07-2020 2:04pm

My setup is similar to Figure 4 on page 46 of this document with a major difference highlighted below.

I have a full TRV set up and 1 valve to control HW. Prior to the installation of the Evohome it was a single zone system.

The call for the boiler comes from the Evohome controller - same for CH and HW. I have a pair of BDR91 relays listening to the controller, one controlling the boiler firing + pump and the other the HW valve. This is because the HW valve is close to the HW cylinder and far from the boiler so it wasn't possible to wire the HW valve to the same relay that connects to the boiler. So the two relays both receive all the controller calls wirelessly but act slightly differently.

When a call comes for CH, only the boiler+pump relay fires. When it comes for HW both the boiler+pump relay and the HW valve relay activate with the latter switching off x minutes after the boiler relay switches off where x is the hot water overrun parameter.

When both HW and CH are called for simultaneously, it is possible that both the HW valve and some TRVs are open. In this case there is no prioritization and both share the boiler heat.

Hope that clarifies the setup. I understand that whether just adding a delay timer between the relay and the pump would work depends on what the HW relay does on a CH only firing. If after a CH only call, the HW valve does not open during the boiler overrun period then simply adding a delay before the pump won't work. The TRVs would have closed before the pump stops. OTOH, if the HW valve opens on boiler shutoff for the overrun period then adding a simple delay timer would work.

deezell · 21-07-2020 7:31pm

garo wrote: »

........OTOH, if the HW valve opens on boiler shutoff for the overrun period then adding a simple delay timer would work.

This is the key. If the above occurs then a timer on the pump is required, or else the HW SL from the relay to the HW valve can be used to supply the pump via the valves aux relay. This would require some wiring though, which you indicated was awkward with the distance between the boiler/pump and the HW valve.

garo · 22-07-2020 9:56am

Thanks. When my understanding of the situation is the same as yours, I know I am on the right track.

scurran19 · 22-07-2020 3:33pm

I'm looking for a little help so I can have an informed conversation with a plumber / electrician about getting a smart thermostat.
I have a Firebird-S 90-120 oil boiler heating both my radiators and hot water and the timer on the boiler has gone. Its a simple old style timer where you pull the pins out, something like this https://heatingpartswarehouse.co.uk/product/firebird-super-q-timeclock/

The problem is everything I read about smart thermostats has the thermostat on a wall in a room with a control panel. Mine is just a knob on the boiler. Hence I don't know if what I am thinking is even possible.

In an ideal world I would replace the timer and thermostat on the boiler with a smart thermostat with Alexa integration where I can set the schedule but I don't know if that's possible with my set up.

For further info there are just 2 zones in the house, upstairs and downstairs and I don't need to be able to control them individually at the moment. It would be nice to be able to heat the water independently of the radiators but I have a feeling that would be a change beyond what I am looking at here and isn't essential.

All help is appreciated!

Clareman · 22-07-2020 3:58pm

The thermostat in the room is really just to turn the heat on or off rather than control the amount of heat coming out of it, so if you have the heat set to 22 and the heat in the room is 21 the boiler will come on and when the thermostat hits 22 the boiler will turn off again. I've the Netamo on a Firebird burner and it's a great job, but I only have 1 zone and no separate water

championc · 22-07-2020 6:48pm

scurran19 wrote: »

I'm looking for a little help so I can have an informed conversation with a plumber / electrician about getting a smart thermostat.
I have a Firebird-S 90-120 oil boiler heating both my radiators and hot water and the timer on the boiler has gone. Its a simple old style timer where you pull the pins out, something like this https://heatingpartswarehouse.co.uk/product/firebird-super-q-timeclock/

The problem is everything I read about smart thermostats has the thermostat on a wall in a room with a control panel. Mine is just a knob on the boiler. Hence I don't know if what I am thinking is even possible.

In an ideal world I would replace the timer and thermostat on the boiler with a smart thermostat with Alexa integration where I can set the schedule but I don't know if that's possible with my set up.

For further info there are just 2 zones in the house, upstairs and downstairs and I don't need to be able to control them individually at the moment. It would be nice to be able to heat the water independently of the radiators but I have a feeling that would be a change beyond what I am looking at here and isn't essential.

All help is appreciated!

Think of any Smart Thermostat as an "external to the boiler" on/off switch. So anyone with a boiler with a similar level of (lack of) control can add a smart thermostat, which will then take the place of the original on/off switch (or be wired in parallel). Of course, you'll need to get wires run from the boiler to where you propose to locate the Smart Thermostat

deezell · 22-07-2020 7:01pm

Or just use a smart stat with wireless connectivity to a relay located at the boiler, which is pretty much all of them. Hive, Drayton Wiser, Nest, Honeywell are wireless by default. Tado is wired but with optional wireless ext Kit. Netatmo available wired or wireless. Other non smart or 'less" smart options are EPH ember, Climote, hub controller and other internet connectable cheap stats on Amazon, many of Chinese origin.

digiman · 22-07-2020 7:31pm

Are there any products out there that will digitally display and record the temperature of the water in your hot water tank?

deezell · 22-07-2020 10:59pm

digiman wrote: »

Are there any products out there that will digitally display and record the temperature of the water in your hot water tank?

This, up to 85°C.
https://www.amazon.co.uk/dp/B0773MX8BH/ref=cm_sw_r_cp_apa_i_LylgFb8X3HPZN

digiman · 23-07-2020 7:26am

deezell wrote: »

This, up to 85°C.
https://www.amazon.co.uk/dp/B0773MX8BH/ref=cm_sw_r_cp_apa_i_LylgFb8X3HPZN

How will this know the temperature of the water inside the tank though?

deezell · 23-07-2020 9:06am

digiman wrote: »

How will this know the temperature of the water inside the tank though?

By attaching the probe to the outside metal surface of 5he cylinder. If you have one if the more expensive double skinned insulated tanks, you'll need something different with a probe sensor to fit into the provided insert tube on the tank.
Look up the Sonoff switch/stat/thermostat device. You can read the temp on an app, and it can act as a stat as well, to fire the boiler. I'm not sure if the app can log or record on going temperature over time, (this is what you want?), but Sonoff can be picked up by all sorts of smart tech and apps, some of the readers here might have done this already.

Irish_peppa · 01-08-2020 10:48am

Has anyone here with a Nest Smart Thermostat know if you can actually get any decent information from it ie: You used your central heating last week for 5 hours . There seems to be no proper usage menu. I get a silly email at the end of each month talking about "leafs" and how many leafs i saved. My god would be better if you had this infomation:
December 2019 Central Heating Usage 60 Hours
December 2020 Central Heating Usage 45 Hours
its a fantastic device but there is no real data that you can use to manage your usage

deezell · 02-08-2020 8:11am

Yes, but referencing unquantified tree bits rather than Joules or Kilowatt hours is much more appealing to the Eco warrior brigade, who queue up to buy at the mere mention of these organic credentials. Maybe they should include a years supply of quinoa or chia with each stat.

chuck eastwood · 02-08-2020 8:16am

Someone hasn't had their coffee yet ðŸ˜…

deezell · 02-08-2020 12:56pm

No, I'm out of the non GM organic fairtrade no airmiles gender neutral non cancelled coffee, so I'll just have to drink the ozone layer destroying stuff. Ahhh!!!!, there goes another rain forest.

Home heating automation

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