Home heating automation

christy c · 13-10-2020 11:02pm

How do know if you have a gravity fed system? Says on Amazon that Drayton does not work with it. House is 25 years old

deezell · 13-10-2020 11:17pm

christy c wrote: »

How do know if you have a gravity fed system? Says on Amazon that Drayton does not work with it. House is 25 years old

Not if there are no zone valves and just a pump. However, if the CH zones are on zone valves, and the HW is gravity, then you can bind the zone valve relay outputs to the HW output from the Drayton, the boiler will fire for any of the 2,/3 zones, and gravity heat the HW. You can have HW only if the CH zones are off, but not CH only. If you have 3 zone valves, your HW is not gravity anymore. I explained gravity mode of a 2 zone timer a few posts back, many non smart electronic 2 zone timers have a built in mode switch to change the two outputs from CH zone and HW zone to Boiler call and circulation pump. Drayton two zone box has no mode switch, in hardware or software. Tado ext kit has it in software by a support call Nest uses 2 pole volt free relays, so you can wire the logic yourself as I showed a few posts back. Any 2 zone timer with CH/HW on and off terminals, with an unwired common for each, can be wired thus.

deezell · 13-10-2020 11:20pm

I should add that you have a gravity HW system if the HW heats without the aid of the circulation pump which supplies the rads.

NewClareman · 13-10-2020 11:28pm

deezell wrote: »

Then Drayton Kit 3 is perfect. It's gone back up in price though from that deal earlier. Now £204.

Hi deezel, Im wondering if I could use 2 x the Drayton 2 kits instead. It would work out much cheaper, as the radiator valves are included. Ive given mote info in the thread I just posted. Is this possible?

graememk · 14-10-2020 12:42am

The Tado systems are on sale on amazon for prime day, as expected.

maxamillius · 14-10-2020 7:44am

deezell wrote: »

Here it is boiler fires for either HW or CH timed event, but pump only operates for CH.

Assume this is exactly how Tado works for gravity systems also?

deezell · 14-10-2020 7:54am

NewClareman wrote: »

Hi deezel, Im wondering if I could use 2 x the Drayton 2 kits instead. It would work out much cheaper, as the radiator valves are included. Ive given mote info in the thread I just posted. Is this possible?

No reason why not, as long as two receivers can be paired to the app, I'd imagine it should work. Its perfectly possible you might have multiple stat zones, more th a 2 stats, so you would need to add 2 kits. The 1 ch zone and the 1 CH+HW kits are £47 and £57, £104. Seems the best way. Those so called 24hr deals can wreck your head though, they appear and disappear in minutes sometimes.

deezell · 14-10-2020 8:14am

maxamillius wrote: »

Assume this is exactly how Tado works for gravity systems also?

Not as such. Tado ext kit has a mode switch for a single volt free 2 pole relay for CH only, or else two live wired outputs, CH and HW, and normally these are used to open their respective zone valves, going live for their independent timers.
For a gravity system, you want the HW terminal to go live for either HW or CH timed event, and this terminal is wired directly to fire the boiler. The CH terminal is wired only to the circulation pump, so either HW or CH will heat HW by gravity, but only CH will pump the running boiler to the rads. Tado support can set the ext. kit to operate this way, while you must set it to mode 2, 2 zone output. You can see from the diagram that in this mode, the zone relay commons are hard wired to live, so it's not possible to use that Nest wiring arrangement, but tado support can make it happen in software.
To that end, you can mimic the gravity mode effect on any 2 zone timer by including CH timing slots on the HW schedule, but that's just a bodge.

christy c · 14-10-2020 8:22am

deezell wrote: »

I should add that you have a gravity HW system if the HW heats without the aid of the circulation pump which supplies the rads.

Given that I can't heat HW on its own through my boiler, would that mean its not gravity fed?

Thanks for the info, you're a wealth of information

savemejebus · 14-10-2020 8:36am

deezell wrote: »

Then Drayton Kit 3 is perfect. It's gone back up in price though from that deal earlier. Now £204.

Keep an eye on this today. The £204 price is not sold by Amazon, if Amazon themselves get more stock in it should be at the discounted price till the end of the day. Also, the multiple zone kit with 1 stat and two smart TRVs is still available and discounted.

Caillte · 14-10-2020 8:44am

graememk wrote: »

The Tado systems are on sale on amazon for prime day, as expected.

Yup bought myself 8 more tado TRVs for £30 each to complete the whole house. Sweet!

captainshamroc · 14-10-2020 10:08am

christy c wrote: »

How do know if you have a gravity fed system? Says on Amazon that Drayton does not work with it. House is 25 years old

From Drayton tech support
If you have no motorised valves on the system it will be gravity, if you have it will be conventional pumped system.

I had a big discussion with their TS over this. I have a 35 year old house and a a single zone boiler they stopped making in the 90's. The hub basically just fires the on switch for the boiler so why would the Drayton hub not work in a gravity fed system. They would never admit that it would work fine but did admit that the reason that gravity fed were not supported was health & safety not technical.

From Drayton tech support
Gravity Fed systems do not comply with part L of the building Legislation. In other words, do not meet the up-to-date building regulation requirements.

i.e. they are not going to invest in testing something that won't go in a new house and if they haven't tested they are not going to say it works fine. I installed and it works fine.

christy c · 14-10-2020 10:20am

captainshamroc wrote: »

From Drayton tech support
If you have no motorised valves on the system it will be gravity, if you have it will be conventional pumped system.

I had a big discussion with their TS over this. I have a 35 year old house and a a single zone boiler they stopped making in the 90's. The hub basically just fires the on switch for the boiler so why would the Drayton hub not work in a gravity fed system. They would never admit that it would work fine but did admit that the reason that gravity fed were not supported was health & safety not technical.

From Drayton tech support
Gravity Fed systems do not comply with part L of the building Legislation. In other words, do not meet the up-to-date building regulation requirements.

i.e. they are not going to invest in testing something that won't go in a new house and if they haven't tested they are not going to say it works fine. I installed and it works fine.

Good to hear. Had pulled the trigger just before you posted!

dendof · 14-10-2020 2:18pm

Didn't want to clog the bargain thread so asking here if possible.
I currently have Nest installed. Looking to make the switch to Tado while it's Prime Day.
But I'm unsure should I get wired, or wireless version. I've attached my current setup and also wondering if I go for wired, is it a straight swap

deezell · 14-10-2020 7:34pm

dendof wrote: »

Didn't want to clog the bargain thread so asking here if possible.
I currently have Nest installed. Looking to make the switch to Tado while it's Prime Day.
But I'm unsure should I get wired, or wireless version. I've attached my current setup and also wondering if I go for wired, is it a straight swap

It's a straight swap if you go wireless, as currently that's what you have, Nest stat wireless to the heatlink relay, which sends wired SL for CH and HW. A Tado stat with an ext. kit relay will exactly replace this. You can't control HW with just a wired Tado stat.

deezell · 14-10-2020 7:41pm

christy c wrote: »

Good to hear. Had pulled the trigger just before you posted!

You're missing the point slightly. A gravity HW system assumes you might want to heat just HW. The system described above is just a CH system with HW as a consequence of heating the rads, hardly practical in the middle of summer. Any stat will turn a boiler on and off. A 2 zone gravity system gives independent HW by virtue of muting the circulation pump giving HW only when the boiler is fired, and the signal logic for this is not available on the two outputs of a wiser CH/HW controller.

christy c · 14-10-2020 7:59pm

deezell wrote: »

You're missing the point slightly. A gravity HW system assumes you might want to heat just HW. The system described above is just a CH system with HW as a consequence of heating the rads, hardly practical in the middle of summer. Any stat will turn a boiler on and off. A 2 zone gravity system gives independent HW by virtue of muting the circulation pump giving HW only when the boiler is fired, and the signal logic for this is not available on the two outputs of a wiser CH/HW controller.

In the system above, if all the TRVs are off would that would heat water? Although possibly not very efficiently?

The ability to turn on CH during the winter remotely, adjust room temperature, turn on single radiators is the appeal for me. If I cannot heat water on it's own during summer thats not a deal breaker by any means.

I have never used my boiler for HW only as it does not have the ability at the moment.

deezell · 14-10-2020 10:36pm

christy c wrote: »

In the system above, if all the TRVs are off would that would heat water? Although possibly not very efficiently?

The ability to turn on CH during the winter remotely, adjust room temperature, turn on single radiators is the appeal for me. If I cannot heat water on it's own during summer thats not a deal breaker by any means.

I have never used my boiler for HW only as it does not have the ability at the moment.

Then you never had a gravity HW heating option.That's ok though, as you are installing a full TRV system, and each one is effectively a zone valve. It matters not if your HW heats by gravity or by circulation pump, in your system calling the boiler using the HW output of the Drayton receiver will result in HW only heating, as all TRVs will be closed. In this instance the pump will send all the boiler water through the cylinder coil, so HW will heat up very quickly and efficiently. You will not be using gravity to heat your water. You only have one input to your existing system to fire the boiler, so simply linking the HW on terminal to the CH on terminal, the boiler will fire for either event but TRVs will only open when their schedule calls for an increase in temperature.

christy c · 14-10-2020 10:43pm

maxamillius wrote: »

I could be wrong but if the TRVs are closed, the circulation pump won’t run, boiler won’t fire and therefore you won’t be able to heat the hot water. You could only hear the hot water whilst you are heating the rest of the house.

As I have said, I am far from an expert on this, but would all TRVs closed not be the equivalent of turning off all radiators and turning on the boiler? How would the boiler/pump know?

maxamillius · 14-10-2020 10:47pm

During the summer I usually leave the stay down and use gravity to heat the water.

I suppose if you had TRVs in every room and these were off, the rooms wouldn’t heat and the water would thus removing the need for a Tado extension kit?

Maybe not the correct way to do it but you would still achieve the same result wouldn’t you?

Basically whenever the boiler is on for a ch timed event, the pump runs, if I have 6 rooms with TRVs and the temperature turned down on them, the rooms don’t heat but the water does.

Am I on the right track?

deezell · 14-10-2020 11:09pm

christy c wrote: »

As I have said, I am far from an expert on this, but would all TRVs closed not be the equivalent of turning off all radiators and turning on the boiler? How would the boiler/pump know?

The stat and reveiver/controller you are buying is the 2 zone device, HW and CH, it will have two live timed output terminals, HW On and CH On. The CH goes live whenever a TRV calls for heat, firing the boiler. The HW one goes live whenever a programmed timed HW event comes on. Simply connecting these two terminals together will ensure the boiler comes on for a HW event even if there are no TRV events, and all TRVs are closed.
If you buy the single zone kit then you just have a CH timer/stat, no seperate relay to close for the app HW timer, so no way to fire the boiler while all TRVs are closed.

christy c · 14-10-2020 11:14pm

deezell wrote: »

The stat and reveiver/controller you are buying is the 2 zone device, HW and CH, it will have two live timed output terminals, HW On and CH On. The CH goes live whenever a TRV calls for heat, firing the boiler. The HW one goes live whenever a programmed timed HW event comes on. Simply connecting these two terminals together will ensure the boiler comes on for a HW event even if there are no TRV events, and all TRVs are closed.
If you buy the single zone kit then you just have a CH timer/stat, no seperate relay to close for the app HW timer, so no way to fire the boiler while all TRVs are closed.

Ta, so stick with what i have? Have 46 mins to decide

deezell · 14-10-2020 11:14pm

maxamillius wrote: »

During the summer I usually leave the stay down and use gravity to heat the water.

I suppose if you had TRVs in every room and these were off, the rooms wouldn’t heat and the water would thus removing the need for a Tado extension kit?

Maybe not the correct way to do it but you would still achieve the same result wouldn’t you?

Basically whenever the boiler is on for a ch timed event, the pump runs, if I have 6 rooms with TRVs and the temperature turned down on them, the rooms don’t heat but the water does.

Am I on the right track?

Not really, if the TRVs are turned down they won't call the boiler, so HW can't heat unless at least one TRV is on. The Tado ext kit supplies a seperate relay terminal which responds to a HW timed schedule. No ext kit, no timer schedule, no way to fire the boiler in either pumped or gravity mode for HW only.

deezell · 14-10-2020 11:18pm

christy c wrote: »

Ta, so stick with what i have? Have 46 mins to decide

If you mean the stat with HW control option( 2 zone) plus all the extra TRVs, yes, go for it.

maxamillius · 15-10-2020 7:00am

deezell wrote: »

Not really, if the TRVs are turned down they won't call the boiler, so HW can't heat unless at least one TRV is on. The Tado ext kit supplies a seperate relay terminal which responds to a HW timed schedule. No ext kit, no timer schedule, no way to fire the boiler in either pumped or gravity mode for HW only.

Fair play to you for putting up with the ridiculous amount of questions, a wealth of knowledge you are!

maxamillius · 15-10-2020 7:02am

Again this might be a stupid question, if I had Tado with extension kit, let’s say I don’t have timed events setup for the hot water, if I decide at say 7 pm that evening I want to put on the boiler for hot water, do I need to login and setup a timer or is there a way of just turning it on, like a boost button maybe?

Also presumably if you were to install TRVs in every room, there is no need for the old wall stag in the hallway?

deezell · 15-10-2020 8:16am

maxamillius wrote: »

Again this might be a stupid question, if I had Tado with extension kit, let’s say I don’t have timed events setup for the hot water, if I decide at say 7 pm that evening I want to put on the boiler for hot water, do I need to login and setup a timer or is there a way of just turning it on, like a boost button maybe?

Also presumably if you were to install TRVs in every room, there is no need for the old wall stag in the hallway?

No need to log into the app on your phone, just open it and set the HW on. You can link it to Alexa, or Smart Things, or via Google voice, a whole host of ways, " Alexa, heat the water", this will boost for a set period, adjustable in the app. Takes a little setting up, but if you're into it you'll know the ropes. I just have CH on my tado, HW is still on the old system on a timer and stat. I never have to go near it, I just keep the cylinder hot as its well insulated. I can boost the CH by voice, OK Google, or Alexa, or by a programmed IFTTT button on my phone.

captainshamroc · 15-10-2020 12:41pm

deezell wrote: »

The stat and reveiver/controller you are buying is the 2 zone device, HW and CH, it will have two live timed output terminals, HW On and CH On. The CH goes live whenever a TRV calls for heat, firing the boiler. The HW one goes live whenever a programmed timed HW event comes on. Simply connecting these two terminals together will ensure the boiler comes on for a HW event even if there are no TRV events, and all TRVs are closed.
If you buy the single zone kit then you just have a CH timer/stat, no seperate relay to close for the app HW timer, so no way to fire the boiler while all TRVs are closed.

A wealth of knowledge as usual.
I had never even considered wiring the HW and CH together. I've plenty of HW in the winter but have to use the immersion in the summer. Could be a solution. I have 2 channel Drayton hub in the box somewhere that I was hanging on to incase I changed the plumbing when my old boiler finally dies.

Skidmcmarx · 15-10-2020 3:43pm

I posted this in the Plumbing & Heating forum but I thought it might be a good idea to ask here too. There seems to be a lot of good information being given.

I've moved into a new to me house recently which had a Climote installed.

We needed to replace the boiler almost immediately as the old one was on the way out. The boiler was installed successfully and is working away fine with the Climote that was there when we moved in.

Now that it's done, we want to move over to Nest.

The Climote is controlling three zones. Downstairs, Hotwater tank & Upstairs

Attached is the wiring of the climote.
We have a stat in the living room and a stat on the landing to be replaced by a nest each.

My question is, based on the wiring seen in the picture, can both nest heat links be places in the same place?

Any insight would be really appreciated.

maxamillius · 15-10-2020 6:28pm

I’ve drawn it all out now and understand how it’s meant to be wired and setup, my only remaining question is,

In my old setup I have a wall stat to switch on the pump for ch. if I was to put TRVs in all rooms, I don’t need the wall stat anymore correct?

In this case I would get the smart radiator kit with the extension, as opposed to the smart thermostat kit? Correct?

And finally is there a requirement to leave one radiator without trv?

Edit

If I decided to just get the smart stat kit, I think this comes with the extension as standard, the wireless stat goes in place of my wall stat and is used to fire Boiler and pump. if I decide to add TRVs at a later date, would I then get rid of the wall stat? Or leave it there in the hall and not put a TRV in the hall radiator?

Home heating automation

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