Home heating automation

Newuser12345 wrote: »

I would like to fix the following issue during the summer when it is easier to get a heating contractor

We had a Horstmann Channelplus H37XL timer with three zones (Z1 Underfloor kitchen , Z2 Upstairs/Downstairs heat and Z3 Separate hot water).

The 3 zones were on a timer and we would hit boost on the 3 buttons if we wanted to turn on heat.

A few weeks ago- we had Nest installed to control Zone 2/3 and planned to leave Zone 1 managed by the timer.
The issue is that Zone 2/3 will not fire independently without Zone 1 being already on.
Nest turns orange but boiler wont fire without Zone 1 being started first

That was fine for the last few weeks as we simply left Zone 1 on but we dont want to have Zone 1 on during summer but would still like to heat water

As above not sure if it was always like this
My question is- do we need a plumber or electrician?

This could be tricky to sort. Do or did you have any existing wall stats on your current system?
Could you previously heat any of your zones completely independently of the others.
Would HW only heat when it's timer was on or would it also heat when any CH zone was on, in other words, once the boiler was running.
Can you identity three seperate motorised zone valves?
Has the installer given you control of HW with the Nest
The Horstman may have a gravity mode switch, in this instance, firing of the boiler is wired directly from the HW SL ( ON or Switched Live), and the other CH timer outputs are used to operate the zone valves. Otherwise, the three SLs would go to their respective zone valves and it is the combined outputs of their relays which provide the SL to the boiler. Have you set the Horstman zone 2 timer to always on? This would be normal when installing a smart stat as the stat (or its heatlink box on the case of Nest) is used to interrupt the SL from that timer zone and take over time and temperature control. Ifym you previously had 3 fully independent zones then the Nest installer has connected it up incorrectly. If you had zone dependency already, Z1 on to make Z2 operate, then you need your system assessed and changed

Newuser12345 wrote: »

Thank you for the reply I appreciate it
- we really dont know if it ever worked- we are in the house 5 years and generally let all 3 zones come on by the timer.
I got Nest to cut down on heating bills and it became apparent then.
It may have never worked

The boiler was replaced 4 months ago and we just continued using the timer

Zone 2 is always on now after install
I believe HW would only heat when boiler was on previously
We have control now of HW via Nest but boiler needs to running first


This is pic of downstairs setup
Second pic is what I believe are 2 Zone valves

https://imgur.com/a/8Bn93dH

Would you recommend an electrician or plumber?

Maybe ask the plumber to recommend a sparks with plumbing control experience. Two zone valves upstairs and boiler downstairs could imply gravity HW from the boiler, but equally the UFH might be pump actuated, with the zone valves for the CH and HW.
Looking at the pic it seems the Nest heatlink relay is wired into the timer, taking over the timing of CH and HW, but if the timer was originally set for gravity HW, then the HW ON terminal would be the one that fires the boiler for any zone timing event, while the other two heating timer terminals would only open the CH and UFH zone valves, but are not electrically wired to fire the boiler.
It's very difficult to assess from the photos only, but is the boiler a wall mounted gas boiler? Is that the bottom of it in the top of the first picture? Regardless, the first task is to establish if your original system was wired to operate 3 seperate zones, and that this was working. Take the cover off the old timer and see if it has a mode switch or jumper on it, ( see link below), an if so, get a picture of it. If it's gravity wired, the HW terminal is used to fire the boiler for any event.
I'm now thinking the Nest installer connected the heatlink CH terminal across Live and CH on, ( Z2), assuming this would open the CH valve and fire the boiler, but with a gravity mode controller the CH terminals only open the valves for CH, the HW terminal goes straight to fire the boiler for all 3 zone events. As the Z2 timer is no longer used for CH events, it will never fire the boiler though the Nest will open the CH valve. This fits your symptoms, as the UFH ( Z1) timing is still in use and still calls the boiler via the HW terminal, whereas the boiler is not called for CH events as its timing is now done by the Nest, and the old timer Z2 zone is probably set to off, so the old timer does not 'know' to fire the boiler via its HW terminal when the CH zone valve opens. You'll need an electrician to study the wiring, and determine if the old timer has a gravity mode jumper and if this has been set ti Gravity mode by removing the jumper,* according to the installation manual). Here's the installation manual for the old timer.
https://drive.google.com/file/d/1-88E6t8lCR02vCTOaksQkrfS-DrN4TBz/view?usp=drivesdk
Also, he should be able to determine if the boiler is indeed fired only from the timer HW terminal, and not by the relays on the zone valves, which I suspect are unused. This will take a bit of plumbing knowledge by the sparks, and will require a little rewiring to accommodate a gravity 3 zone timer with one zone delegated to the Nest. I'll knock up a diagram of how it should be done, probably be next week. Meantime, check if those zone valves are for UFH and CH, and that both are closed when HW only is called. They should have little indicator lamps on them when on.
EDIT; Just reread your original post, and you say zone 3, HW, also requires Z1 to be on for Z3 HW to heat, so this seems to confirm my suspicion, as the Nest installer will have also bypassed or interupted the Zone 3 timer in some way, meaning only Z1 is calling the boiler via the old Z3 terminal.

I'm getting a new combi boiler in the next few weeks. The installer has offered to install a Tado thermostat for 250€ extra. I'd prefer a Nest as I have full Google Home already, what do people think? Is it easier to just buy a Nest myself and get it installed or any reason to go for the Tado?

deezell wrote: »

If the €250 includes the stat and bridge it sounds good. If you already have a manual wall stat then installation is a trivial swap for a Tado. Putting the Nest in place of the old wall stat can be fiddly as you have to isolate the stat wires to connect them to the the Nest receiver ( heatlink) back at the boiler. You can connect the Nest wirelessy, but then you have to power it from an adaptor. Ask him to price a nest install. I'd guess an additional €150 or thereabouts, depending on the kit price, and the extra time to wall install.

Not quite sure what you mean by bridge for the Taxi? But I do already have a wall stat in there. You think 150 to install the Nest even if I supply it myself?

loyatemu wrote: »

any thoughts on why there are 2 live and 2 neutral tied together running into the backplate?

There is a separate wiring junction box in the same cupboard as the valves so I'd imagine the Drayton can be wired up in there, but it would be easier to have it go where the existing controller is (I bought it anyway, couldn't resist the £50 off).

got this installed at the weekend. I wasn't able to do a straight swap for my existing controller as the 2 heating zones were wired together at the junction box and a single wire ran from there to the old controller. Running an additional wire to separate them out wasn't practical.

Instead I put it where the old downstairs thermostat was (probably a better location for WiFi anyway) as there was already a 5-core cable running back to the junction box from there. So the mains supply for the Drayton comes via the old controller (which is set to "Manual On") and the old thermostats are fully disconnected.

The initial setup is finicky as you first connect your phone to a WiFi hotspot created by the Wiser Hub, but during the setup the Hub connects to your home WiFi and you lose contact with it unless you also reconnect to the home WiFi, something that isn't mentioned anywhere in the setup instructions.

Having got it setup though, I'm pretty happy with it, obviously not using the heating much at the moment but the system is well designed and easy to understand and I like the graph the tracks the room temperature against the program.

Think I am going to get a Drayton 2 zone + HW installed shortly. Anyone that has one of these find any shortcomings with it?
Also can they be worked manually should the WiFi fail or someone hasn't access to the app?

AFAIK it will work away without internet access. If there's no WiFi at all in the house I assume the app will no longer work but you can turn the heating and water on from the thermostats and the hub manually. So far pretty happy with system, heating came on this morning due to this crappy weather.

The app shows the relative temperature of your rooms, outside and the temp you have set in the app all on a graph which is useful to see. Whether it saves me any money, I have my doubts. If I had the individual radiator thermostats in each room it would be better but that would be a big job to get done as we don't have TRVs already.

You don't need the wall mount plate, the stand is just a base with a power supply connection, and the Nest connects wirelessly to the Heatlink box. You currently have the nest connected with a wired connection to the heatlink, these wires provide power to the Nest and also carry the digital signals between Nest and Heatlink.
With the wireless configuration, the Nest just needs power, and a little phone style supply was included in the kit. If you have this supply, pop off the Nest and power it with this. If your nest was originally wirelessy paired to the heatlink, it will connect, and you will be able to site the Nest anywhere. If not already paired you'll have to follow the installation steps for this.
The stand is just a stand. I don't think it comes with the power supply as you should have this. The base pictured is for wired connections only.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://nest.com/support/images/misc-assets/Nest-Thermostat-Installation-Guide-UK.pdf&ved=2ahUKEwi30_CbpZPjAhWVSxUIHQOeC8wQFjAAegQIAhAB&usg=AOvVaw0fz-LeJmoOgdPkUiCznvNG

I 'stand' corrected. It's way back since I installed this, a generation 2. I recalled an image of the stand with the power unit attached. I've dug up the documents, you do indeed have to clip the base into the stand. In fact, the plastic stand was supplied with the 2nd Gen Nest, it was no more than a piece of moulded plastic, a euros worth. I see now they're charging €40 for the same. Plenty of inexpensive alternatives, and some really nice stainless steel ones on eBay for half the price.
You'll just have to pop the base off the wall, but don't worry, no high voltages there, just take out the 2 wires, snip off the conductors and tape up.

https://images.app.goo.gl/HPKxWLjnShgi7Foc8

Ah I see, well in that case you should just add the wiring base to the stand, and just move the entire assembly around. If you have a table and mains plug nearby to the original wall location, that's all you'll need.
To move it the way you'd like will require getting an additional wiring baseplate (sometimes called motherboard). Very difficult to find, unless you find someone selling a stand complete with wiring base. Nest seemingly don't want to sell them as a part, but I've seen $100 being asked for US style ones (more wiring terminals, no heatlink used, direct wiring to boiler). I think it may be to prevent sales of stolen nest stats, I've seen some for sale on ***** sans the baseplate.

Having finally moved in to our newly renovated home, im starting to get to grips with the heating system installed. A Glow System 30 Boiler and a Joule 200L Cyclone Tank.
I managed to wrangle a Netatmo thermostat from our supplier Energia and I bought a second one on the very cheap so both zones are covered.
I wired the relay with the help from the electrician so that the relay replaces the wall mounted thermostats and the Netatmo thermostat can be moved between the Kitchen and living room. Thats all working great seemingly although it now too warm to go testing.

What can I do to make the HW thermostat "smart" and have a little more control over the Joule tank?
At the moment its controled via schedule set on a CTC EasyProg 3. What does the stat on the side of the tank actually do if the boiler comes on for an hour in the morning and evening?

deezell wrote: »

Netatmo smart stats do not have the option to control HW timing, Hive, Tado, Nest, Drayton might have been better choices.
Is your system a true three zone with independent zone valves for the two CH zones and the HW zone, or does HW heat if any of the two CH zones are called (HW gravity mode). The ezi prog 3 can he configured for gravity mode, wherby all calls for CH1/2 and HW open the HW relay, which alone controls the boiler, while calls for CH2 and CH2 power respective zone valves or zone pumps.
The thermostat fitted to the side of the HW cylinder would be used to interrupt the boiler when the required HW temperature is reached, if this happens during the HW timed schedule. If the HW has its own zone valve then HW can be heated independently of CH, and conversely CH calls will only heat radiators. If the HW is heated for any CH call ( gravity mode) then the HW tank thermostat can't be used to halt the boiler when HW reaches set temperature during a CH call, so the HW may heat hotter than required.
If you have a three zone valve system then it will work fine, limiting HW temperature during the scheduled time slots. If you want app control of the HW timing, you could add a cheap Sonoff relay to make HW calls instead of the eziprog. If you also want to control HW temperature by app, there is a SonOff relay with a temperature probe that can replace the presumably mechanical one on your HW cylinder. Virtually all the other HW control enabled smart stats only allow timing schedules for HW, temperature control, if at all, is done by the mechanical cylinder stat. I can't think why you would want a range of temperatures for your HW taps, generally 55 to 65 is the temperature set on the cylinder stat, and this won't be exceeded unless your cylinder is heating due to CH calls and the boiler water temperature is set much higher than your HW cylinder stat. Again this is not that likely, most boilers will be set to about 60-70 degrees for the water circulating through the rads and through the HW cylinder coil.

Mowers and heating systems, thanks for the advice deezell!!
Yup, I knew the Netatmo didnt do HW but I prefer the no recurring fees and the interface performs great IMO. Once you wire the relay to the thermostat that is.


Yes, the system is true three zone with three valves that operate each zone individually. The valve on the HW however, looks different to the other two that have a fancy LED so you know they are on or not.


Thats a good description of the thermostat on the side of the HW tank. Based on that, maybe I dont need anything smarter?? I mean, we only ran out of water once without knowing and I guess this is what Im trying to avoid. It only taked 30mins to heat it back up to temp so its hardly that bad.
I just thought it would be nice to have a similar graph output from the Netatmo but for the HW so that we could plan the HW heating a little better and set the thermostat temp a little lower too. Currently its at 45 degrees.

deezell wrote: »

I've said this many times before in this thread. If you have a modern fully enclosed insulated cylinder, (and you do, one of the best), then there is little advantage in trying to squeeze your HW heating times to the minimum. You'll save nothing as you'll have to burn gas to heat it up if it goes cold. The heat loss from this cylinder is tiny, so what are you saving by leaving it with the minimum of HW inside, as so little of this is lost anyway. Just put it on constant on the timer, or for longer and more frequent time intervals. Set the temperature as low as 45 if you wish, the thermostat will control the amount of times the boiler fires, not the schedule. If you want to get an idea of the efficiency of this cylinder, measure the temperature inside the cupboard or hot press where I assume it's located, if you have a little bulb thermometer of some sort. See how warm it is , then set the schedule for always on, and recheck the temperature a day or or so later. I'd be very surprised if there's more than a couple of degrees in the difference, if any.
Turning on and off HW heating is a legacy of The old uninsulated cylinder era. (Remember Des Bishop's comedy routine about LEAVING ON THE IMMERSION!!!)? With the new cylinders, what you don't use stays hot for days, so low are the losses, so there's little to be saved by trying to replicate heating on demand, which is what timing was all about. Best way to actually save on HW is to take cold showers, but I like the idea of set once and forget. No tinkering with timers, stats, boost buttons, that's sooo 80's darling!!

Excellent, thanks again for that explanation and it probably answers why I cant find anything smart to attach to the cylinder.
It and the boiler are located in the garage outside that is not yet sealed up at all. I need to get that done before winter.

I might add, if its in the garage, definitely don't turn it off for long periods during winter absence. Aside from frost protection, the general reliability of any system is increased by operating at a steady temperature. It's true for most devices from engines to electronics. Cool down and heat up create many stresses in objects constructed from different materials, causing component and structural failures at a higher rate than if left on. As an extreme example, Glass making furnaces once heated are never turned off, it's too costly to get them up and running again.