Home heating automation

deezell wrote: »

With gravity HW, it always heats when the boiler is on, and will heat to the temperature of the boiler output. A stat on the cylinder is no use unless put in a motorised valve the only other option is to lower the temperature of the boiler flow, using the boilers own jacket stat. Depending on your boiler model, this may be analogue or digital. If you set this to 55-60°, then your HW will never exceed this temperature, as the boiler will cut and limit its flow temperature, but the risk is your radiators will not be able to heat up as quick or maintain room temperature if the flow temp is limited. Your boiler will be a bit nore efficient though if it cylcles for longer but at a lesser temperature. You may have it set to operate at up to 70°, and when CH is on it might never reach this if the boiler output is close to CH demand, but when its heating HW only, its going to reach max temperature very quickly and overheat your cylinder.

So before installing Tado ext with TRVs would you recommend getting a motorised valve installed along with a cylinder stat?

DM1983

Repeating my post from plumbing forum because I got no response.

I had an old school heating setup in my old house, nothing zoned, no smart controls. I added salus smart controls and was able to split hot water and central heating into separate zones with motorised control valves.

Just into a new (old) house and back where I was, no zones. I bought a 3rd gen nest thermostat this time as I wanted to upgrade from the salus setup but from what I'm reading now, I can't just plug in the nest in the same way that I had the salus in my old house? Do I need another separate nest to control hot water only?

Basic ideal gas boiler.

maxamillius wrote: »

So before installing Tado ext with TRVs would you recommend getting a motorised valve installed along with a cylinder stat?

Yes, but in order to have CH independence from a call for HW, you will need either a full TRV set on all rads, or else a motorised valve on the HW circuit also, creating a proper 2 zone S plan.
If you just install a HW valve off a cylinder stat to cap HW temperature, this will work fine in your current system, with a single timer for the boiler for both events, the wall stat operating the pump gor CH and the cylinder star opening the valve for HW heatingw. If you install the tado and ext kit subsequently, you now have individual timers for HW and CH, and with only one motorised valve you don't have a way of calling the boiler only without a flow to CH, as the pump will now be tied to the boiler for a HW or CH call, whereas previously the pump only came on for a CH stat call. Its hard to explain this in words without reference to wiring, but you will need either two motorised valves, or an all TRV and single HW valve to avoid cross calling, ie, HW call only causing rads to heat.

DM1983 wrote: »

Repeating my post from plumbing forum because I got no response.

I had an old school heating setup in my old house, nothing zoned, no smart controls. I added salus smart controls and was able to split hot water and central heating into separate zones with motorised control valves.

Just into a new (old) house and back where I was, no zones. I bought a 3rd gen nest thermostat this time as I wanted to upgrade from the salus setup but from what I'm reading now, I can't just plug in the nest in the same way that I had the salus in my old house? Do I need another separate nest to control hot water only?

Basic ideal gas boiler.

The nest receiver box, known as the heatlink, has two volt free switched outputs, one each for timed HW and timed/temperature controlled CH. You'll need to have two motorised valves installed to create the physical plumbed zones in order for the Nest to control them, with an S plan wiring scheme from the valve relays to fire the Boiler.

deezell wrote: »

Yes, but in order to have CH independence from a call for HW, you will need either a full TRV set on all rads, or else a motorised valve on the HW circuit also, creating a proper 2 zone S plan.
If you just install a HW valve off a cylinder stat to cap HW temperature, this will work fine in your current system, with a single timer for the boiler for both events, the wall stat operating the pump gor CH and the cylinder star opening the valve for HW heatingw. If you install the tado and ext kit subsequently, you now have individual timers for HW and CH, and with only one motorised valve you don't have a way of calling the boiler only without a flow to CH, as the pump will now be tied to the boiler for a HW or CH call, whereas previously the pump only came on for a CH stat call. Its hard to explain this in words without reference to wiring, but you will need either two motorised valves, or an all TRV and single HW valve to avoid cross calling, ie, HW call only causing rads to heat.

Thanks Deezel, I think that makes sense, I’m going to draw it out in the morning and see how it all fits together. Ideally I would like to go fully TRV on the rads with Tado but I would definitely like a way of capping the temp in the cylinder also.

DM1983

Thanks for reply. That sounds promising. So one Nest thermostat and one heat link can control CH and HW separately once the motorised valves and plumbing is correctly installed?

deezell wrote: »

The nest receiver box, known as the heatlink, has two volt free switched outputs, one each for timed HW and timed/temperature controlled CH. You'll need to have two motorised valves installed to create the physical plumbed zones in order for the Nest to control them, with an S plan wiring scheme from the valve relays to fire the Boiler.

DM1983 wrote: »

Thanks for reply. That sounds promising. So one Nest thermostat and one heat link can control CH and HW separately once the motorised valves and plumbing is correctly installed?

Yup.

Can get the Wired Thermostat Tado for 100 quid, looks to be decent value?

JohnDeereIE wrote: »

Can get the Wired Thermostat Tado for 100 quid, looks to be decent value?

Is that just as an additional stat, or as a starter kit with the bridge.

deezell wrote: »

Is that just as an additional stat, or as a starter kit with the bridge.

Starter kit, some other deals......

Refurbished from Tado
https://www.tado.com/ie-en/certified-refurbished

JohnDeereIE wrote: »

Starter kit, some other deals......

Refurbished from Tado
https://www.tado.com/ie-en/certified-refurbished

That is good. I think that's what I paid for my Maplin B stock v.2, a good few years ago. Especiallly as it includes delivery, it's priced in €, and theres no Brexit induced VAT surprises.
UK is definitely going to take a hiding on it's online sales, deal or no deal, unless suppliers sign up to OSS and collect and remit VAT on behalf of the EU. Sovereignty my h**e. Post that link on the bargains thread.

deezell wrote: »

That is good. I think that's what I paid for my Maplin B stock v.2, a good few years ago. Especiallly as it includes delivery, it's priced in €, and theres no Brexit induced VAT surprises.
UK is definitely going to take a hiding on it's online sales, deal or no deal, unless suppliers sign up to OSS and collect and remit VAT on behalf of the EU. Sovereignty my h**e. Post that link on the bargains thread.

Wil do later when on laptop. Just wondering would it make sense to buy the Wireless kit with hot water controller as well now?
The refurb kit has same warranty so no huge risk IMO

JohnDeereIE wrote: »

Wil do later when on laptop. Just wondering would it make sense to buy the Wireless kit with hot water controller as well now?
The refurb kit has same warranty so no huge risk IMO

If you want to time your HW, or better still, experiment with the location of the (wireless) stat, then only €35.

deezell wrote: »

Yes, but in order to have CH independence from a call for HW, you will need either a full TRV set on all rads, or else a motorised valve on the HW circuit also, creating a proper 2 zone S plan.
If you just install a HW valve off a cylinder stat to cap HW temperature, this will work fine in your current system, with a single timer for the boiler for both events, the wall stat operating the pump gor CH and the cylinder star opening the valve for HW heatingw. If you install the tado and ext kit subsequently, you now have individual timers for HW and CH, and with only one motorised valve you don't have a way of calling the boiler only without a flow to CH, as the pump will now be tied to the boiler for a HW or CH call, whereas previously the pump only came on for a CH stat call. Its hard to explain this in words without reference to wiring, but you will need either two motorised valves, or an all TRV and single HW valve to avoid cross calling, ie, HW call only causing rads to heat.

Think I have the wiring sussed for Tado (Diagram attached)if I was to install a valve on HW with cylinder stat, where does that get wired to?

deezell wrote: »

If you want to time your HW, or better still, experiment with the location of the (wireless) stat, then only €35.

I was going to buy the wired kit for 100 and then the wireless for 135. From reading I can use the wireless as a add on the the existing wired kit and use the hot water controller for the water. Sell on any spare kit. Or am I just nuts :-)

maxamillius wrote: »

Think I have the wiring sussed for Tado (Diagram attached)if I was to install a valve on HW with cylinder stat, where does that get wired to?

Thats the ext kit wired in gravity mode, all requests for the boiler, HW timer or CH stats or TRVs, results in the HW relay closing and firing the boiler. HW is heated by gravity, no circulation pump. Any CH call will in addition turn on the circulation pump. This mode can be self configured or by Tado support.
HW will continue to heat during a CH event, it's temperature a function of the boiler set temperature and the working temperature of the heated flow, dependant on boiler output and the number of open TRV rads. In this congfiguration, a HW motorised valve could be inserted in cylinder flow and closed by a cylinder thermostat NC contact which would remove the SL frim the valve when cylinder temperature is exceeded. This would be a passive limit, like a mechanical TRV on a rad, the boiler would continue to fire to its own internal max, until the HW timed event ended. To have the boiler cease firing during a HW only event when the cylinder stat opens, but continue to fire while a CH event is live, requires additional relays, or a plumbed S plan non gravity system with two valves. If you're getting a HW valve installed at the hot flow tee, it's trivial work to get a second valve installed on the CH flow, and implement S plan, even if there are smart TRVs on all rads.

JohnDeereIE wrote: »

I was going to buy the wired kit for 100 and then the wireless for 135. From reading I can use the wireless as a add on the the existing wired kit and use the hot water controller for the water. Sell on any spare kit. Or am I just nuts :-)

Possibly

Why do you want two wall stats, do you intend installing motorised valves and two plumbed CH zones?

deezell wrote: »

Thats the ext kit wired in gravity mode, all requests for the boiler, HW timer or CH stats or TRVs, results in the HW relay closing and firing the boiler. HW is heated by gravity, no circulation pump. Any CH call will in addition turn on the circulation pump. This mode can be self configured or by Tado support.
HW will continue to heat during a CH event, it's temperature a function of the boiler set temperature and the working temperature of the heated flow, dependant on boiler output and the number of open TRV rads. In this congfiguration, a HW motorised valve could be inserted in cylinder flow and closed by a cylinder thermostat NC contact which would remove the SL frim the valve when cylinder temperature is exceeded. This would be a passive limit, like a mechanical TRV on a rad, the boiler would continue to fire to its own internal max, until the HW timed event ended. To have the boiler cease firing during a HW only event when the cylinder stat opens, but continue to fire while a CH event is live, requires additional relays, or a plumbed S plan non gravity system with two valves. If you're getting a HW valve installed at the hot flow tee, it's trivial work to get a second valve installed on the CH flow, and implement S plan, even if there are smart TRVs on all rads.

Cheers for that mate, think I’ll just fire ahead with the Tado and TRVs for the moment and forget the cylinder temperature. Looks like a good deal on the refurbished Tado extension kit

maxamillius wrote: »

Think I have the wiring sussed for Tado (Diagram attached)if I was to install a valve on HW with cylinder stat, where does that get wired to?

IF you want a limit motorised valve on the HW flow pipe, and you want to retain gravity mode ( HW heats for either CH ot HW events), you can do this by installing a valve with a two pole relay, which has NC connected to the pump SL, and NO connected to HW-ON SL, with COM to the boiler. This will ensure the boiler continues to fire for a CH event when the cylinder stat opens, but cuts when only an HW event is on and the cylinder reaches temperature. Some 2 port valves only have COM and NO relays, orange and grey wires. A 2 pole relay valve has a NC contact, usually a white wire. Now where did she hide tge Quality Sreet...

deezell wrote: »

Possibly
Why do you want two wall stats, do you intend installing motorised valves and two plumbed CH zones?

I read, maybe incorrectly if you have a room with a number of rads instead of installing multiple thermostats on the radiator to install a wireless wall stat

JohnDeereIE wrote: »

I read, maybe incorrectly if you have a room with a number of rads instead of installing multiple thermostats on the radiator to install a wireless wall stat

With mutiple rads, all with smart TRVs, you can put on a wall stat to act as the temperature measuring device on their behalf, all the trvs in that room or area become slaved to the stat, no longer using their own built in stat. You can equally do the same in a room with mutiple smart TRVs by slaving all.of them to a single one, which acts as the temperature measuring device for all.
Now you're suggesting to use a wall stat to control a group of rads without their own TRVs in a room/ area. This will work if the room/area is separated at the plumbing level by a motorised valve, becoming a zone to which the wall stat controls the flow of CH hot water. If all your radiators heat when the heating is on, having more than one wall stat won't seperate them into zones. You have to fit electric valves in the pipework, or smart TRVs, which are also controllable valves, on each rad. From your previous posts you state your heating system is one big zone, all on or all off, excluding mechanically turning individual rads off of course. Fitting smart TRVs can be an economical way of achieving zoning, if your rads already have the correct type of valve body on the rad, which the TRV head can control. Fitting a large plumbed in valve to the pipework to say, seperate upstairs from downstairs, requires a level of plumbimg skill, and that's only if the single zone can be separated at an early stage into the required piped sections. Many 2 story houses are plumbed in a loop inside the space above the ground floor ceilings, with pipes rising up to the bedroom rads, and down inside partition walls to the ground floor rads. Such a setup is impossible to split into up/down zones, and can only be separated by smart TRVs.

deezell wrote: »

With mutiple rads, all with smart TRVs, you can put on a wall stat to act as the temperature measuring device on their behalf, all the trvs in that room or area become slaved to the stat, no longer using their own built in stat. You can equally do the same in a room with mutiple smart TRVs by slaving all.of them to a single one, which acts as the temperature measuring device for all.
Now you're suggesting to use a wall stat to control a group of rads without their own TRVs in a room/ area. This will work if the room/area is separated at the plumbing level by a motorised valve, becoming a zone to which the wall stat controls the flow of CH hot water. If all your radiators heat when the heating is on, having more than one wall stat won't seperate them into zones. You have to fit electric valves in the pipework, or smart TRVs, which are also controllable valves, on each rad. From your previous posts you state your heating system is one big zone, all on or all off, excluding mechanically turning individual rads off of course. Fitting smart TRVs can be an economical way of achieving zoning, if your rads already have the correct type of valve body on the rad, which the TRV head can control. Fitting a large plumbed in valve to the pipework to say, seperate upstairs from downstairs, requires a level of plumbimg skill, and that's only if the single zone can be separated at an early stage into the required piped sections. Many 2 story houses are plumbed in a loop inside the space above the ground floor ceilings, with pipes rising up to the bedroom rads, and down inside partition walls to the ground floor rads. Such a setup is impossible to split into up/down zones, and can only be separated by smart TRVs.

I should really stop reading websites :-) My original plan was to buy the main thermostat which I have done, then put smart radiator thermostat onto all radiators and work from that. I was trying to get too clever and better off sticking to original plan.

So I’ve just pulled the trigger on the Tado wireless stat with extension kit..

Two questions...

1. Is the heating actually ever turned off? When I’m going to bed do i need to lower the stat right down so that the boiler doesn’t fire during the night?

2. My current wall stat is in the hall, coldest place in the house, now that i will have the wireless stat, is there anywhere better to place it?

I have not gone for the TRVs yet ill upgrade as time goes by,

maxamillius wrote: »

So I’ve just pulled the trigger on the Tado wireless stat with extension kit..

Two questions...

1. Is the heating actually ever turned off? When I’m going to bed do i need to lower the stat right down so that the boiler doesn’t fire during the night?

2. My current wall stat is in the hall, coldest place in the house, now that i will have the wireless stat, is there anywhere better to place it?

I have not gone for the TRVs yet ill upgrade as time goes by,

Not right down, maybe a cooler but not baltic temperature. Depends on how fast your rooms lose heat, but you might want to maintain 16 to 18 as your minimum. If the hall is the coolest room, set it lower, so it wont kick in unless it gets really cold there, by which time bedrooms would be a few degrees above the hall.
You could try the stat in the kitchen or living area, where you soend your most waking hours. Heres a typical schedule for a centrally placed stat in a bungalow.

And a typical winter 24hrs for the same stat.

deezell wrote: »

Not right down, maybe a cooler but not baltic temperature. Depends on how fast your rooms lose heat, but you might want to maintain 16 to 18 as your minimum. If the hall is the coolest room, set it lower, so it wont kick in unless it gets really cold there, by which time bedrooms would be a few degrees above the hall.
You could try the stat in the kitchen or living area, where you soend your most waking hours. Heres a typical schedule for a centrally placed stat in a bungalow.

And a typical winter 24hrs for the same stat.

So during the night does your boiler ever fire?

limnam

maxamillius wrote: »

So during the night does your boiler ever fire?

It'll fire at night if the stat goes below 17.5

limnam wrote: »

It'll fire at night if the stat goes below 17.5

Ye makes sense, I suppose I’m wondering what temp my house/hall actually gets too during the night, genuinely would have no clue and wouldn’t want the boiler to be firing

maxamillius wrote: »

Ye makes sense, I suppose I’m wondering what temp my house/hall actually gets too during the night, genuinely would have no clue and wouldn’t want the boiler to be firing

Even if it's freezing?

Clareman

maxamillius wrote: »

Ye makes sense, I suppose I’m wondering what temp my house/hall actually gets too during the night, genuinely would have no clue and wouldn’t want the boiler to be firing

But you won't be in the hall during the night so don't worry about it, if you have a single zone system then pick a room. Personally, I've the master bedroom picked, yes the 2 of us are in it at night so it's warm but it works well.