Home heating automation

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When you have a smart TRV valve in the same location as it's zone controller stat, you put them in the same 'room', and they use the same schedule. Importantly, set the 'measuring device' of the TRV as the stat. This turns the TRV into a simple motorised valve controlled by the stat. If the stat, as zone controller, is called by another TRV to fire the boiler, it will close it's relay to do so but will not wirelessly open the colocatedTRV which it controls while its own internal sensor is at target temperature. In this instance the stat is just acting as a boiler relay for the other TRVs that are using it as zone controller.

Thanks Deezell !!

You already know enough to avoid being bulls****ed. If you consider your seperate HW first, how is it currently heated, is it only while all the rads are on? Is the cylinder upstairs. Can you trace a seperate flow and return from the boiler to the cylinder. Can you trace a seperate flow and return for upstairs in general. Seperating these plumbed zones is key to a zoned system. Even if you can clearly identify a seperate circuit to upstairs, the cylinder may be tapped off it at an arbitrary point, making it impossible to close flow to all the upstairs rads using a single zone valve.

Is the entire system 20 yo or just the boiler. It would be surprising to have an installation from the 2000s that didn't at least supply the cylinder on its own circuit, either by gravity convection, or by a zone valve on the CH. This was often as simple as running the boiler with the circulation pump off. Hot flow and return ceased to the rads, but went by gravity convection to the cylinder. Is the old boiler gas or oil? Gas is generally pumped for all flows, whereas a ground floor installed oil boiler indoors would likely have a gravity split for HW, then a recognisable further split for up and down CH. This is the only configuration that is easily plumbed into zones by the insertion of motorised valves.

If the flow and return are randomly tapped for CH and HW, as in many houses the flow/return is piped in a loop in the 1st floor ceiling, with ground floor rooms fed from pipes going down in the partition walls, and 1st floor rooms from risers, (the cylinder could be anywhere in this mix), then your only economical recourse to zones is to install Smart TRVs. This will give you multiple CH zones, but also independent HW as with all TRVs closed the cylinder alone can be heated.

So first job is to try and get an accurate idea of your existing plumbing. Splitting to zones and isolation of the HW circuit may be infeasible or prohibitively expensive. If concrete floors need to be dug to find branches, I'd call a halt straight away. The advantage of TRVs is that you can get your new boiler, get each rad fitted with a €20 trv valve body, with or without mechanical trv head, install your Tado for the general single zone, and in stages remove the mechanical TRV heads if fitted and replace with smart TRVs onto the valve bodies.

If you manage at a minimum to isolate the HW heating, you'll have a grant enabled system, and even a partial implementation of TRVs will be sufficient to increase efficiency by capping and closing lesser used rooms, but leaving general purpose areas such as the hall and bathroom open for any CH timed event.

Somewhere on this thread last year a poster gave a real costing for supply and fit of a TRV valve head per rad based on a full house set, but not including the smart heads or their configuration. I think it may have been in the region of €70-80 per rad, but you'd have to trawl back unless the poster reads this and obliges. I'll have a root myself to see.

Any thoughts or suggestions for the following set up, post refurb?

- New combi condensing boiler - Weissman Vitodens 111

- 5 zones ufh, downstairs

- 6 rads upstairs

I liked Nest before doing refurb. Like being able to turn on heating before getting home, and turning on water too (had traditional boiler and hot cylinder).

I'm not convinced I need too much now by way of automation....rhe house is being deep retrofitted so can maybe cope with relying on stats for ufh, and manual intervention for rads when needed.

But I'm probably missing something....what would people recommend with this set up?

What do you currently have by way of control. Wall stats? Any stat upstairs? Zone timers or controllers? With deep retrofit and ground floor UFH, you won't have any great advantage in tweaking ground floor settings, unless you're away for long periods, as the response time is relatively slow, Upstairs might produce some savings by a general smart schedule, or individual TRVs, but if the rooms are high spec insulated, it will be hardly noticeable as low loss to the outside and heat transfer rising from the ground floor and between open doors upstairs tends to even out the temperature spread. The most savings with smart thermostats occurs in poorly or even modestly insulated homes, where you can selectively turn down or off little used rooms, and focus your heat where its required at given times.

You could try manually simulating a scheduled system by turning ufh stats up and down at different times of the day, see if it creates better comfort where required, or unacceptable cold spots. If they're not already on a timer, turn down at night and on again early in the morning. You don't need the kitchen at 20° at 3:00am, so there are some saving to be had by allowing steady cooling during the small hours, and restoration before everyone gets up. As I said, cold draughty houses produce the best smart thermostat results.

Nice little DIY project, zero cost.

I have a 3 zone heating system. My programmer is an EPH R37 HW which has no wifi function so cant use the ember app with it.

Is it simply a job of replacing the programmer itself with an EPH R37 RF with a gateway and I'll be able to use the app?

Thanks in advance

Thanks for the reply, doing the install today. I notice I have a black wire on the old Mechanical timer, is this to the thermostat out in the boiler? Do I remove that black wire from the equation, to attach it to slot 1 on the hive backplate? I attach some pics so any help with the wiring is appreciated.

Apologies, I can't figure out how to rotate media when attached.

Thanks again for your help, advise and understanding is invaluable. I installed it and all the lights look good, just no spark from the boiler. I will reseat the Black switched live again as its the only wire as per your instruction that fires the boiler.

100% on the money, was a neutral. What you don't see in the pic and what I only noticed now when I went back, is that it was 4 core cable used, hence the Earth/Neutral. Thanks for your help with this, know a bit about somethings, but clueless when it comes to wiring. All fired up and working as expected, had to pop it into Gravity fed mode as I had a cold tank in the attic and the hot water cylinder in the hotpress, seemed its only the Rads being pumped.

Yes, Gravity Fed mode on the Hive Receiver - I did this as I read (below) in the setup that it matched my system, or so I thought. The receiver when on, has the CH and HW buttons lit - HW and Rads get hot. It all seems to be working, but based on previous wiring, might just be luck! (House was plumbed and sparked by apprentices back in the boom of 2003!)

I don't think my system pumps the HW to the cylinder in the hotpress, have the cold tank in the attic, the pump only seems to push to the rads, maybe my understanding is wrong. Should I revert back to normal mode on the Hive receiver?

Just the single zone yes, no stats anywhere, only temp control seems to be on the Boiler Outside (just above the Firebird sticker in the pics above). No other switches, pump is outside on the boiler/burner but no idea what or where it pushes to, Rads/HW/Both?. I have the Hive in Gravity mode currently and seems to be working. I just switched it back to Non Gravity and works also. Does it now matter which mode the Hive Receiver is in?

No, it makes no difference per se as you only have one relay connected, the CH ON, but if you set it off using a HW only schedule, nothing will happen as the CH relay is the only one connected. You can test if gravity HW only is possible by disconnecting the circulation pump power, and firing the boiler on it's own, but if the hot flow pipe drops below the boiler on the way from the shed, then no convection flow will occur to the HW cylinder. If the HW has a distinct seperate tee off of pipes from the boiler flow and return to the CH , you can get motorised valves plumbed in at that point to enable seperate zones for CH and HW.

Screwfix have Honeywell Evohome. Compare prices to Amazon and see, but Amazon UK will only adjust the VAT to Irish, no duty unless the order is over €150. You could buy individually to avoid duty, which is 2% I think as Evo are European made. Screwfix can obviously bring in directly from the EU, so should be competitive with amazon UK, and easier for returns.

CPC Ireland who are Irish Honeywell distributors only seem to have a few basic stats on their site.