Efficient multiroom scheduling

Unkledunkle

I have smart thermostats on all my radiators (7), with schedules set for each room according to their use. Had the full set for a year. In terms of targeted comfort and (slightly clunky) access to reports and detailed charts, we love it, great. Before that I just had the central tado thermeostat. That saved me some money compared to my old dumbstat, and the multi-smart valves have definitely saved me more due to only needing to heat the rooms to 'warm' when we know they'll be in use, and the rest of the time they can be scheduled to a cooler level.

Definitely saved me money, I'm not unhappy.

The question is though:

Is the system smart enough to all work together to prevent, say, short gaps in heating?

I'm not so worried about short cycling - the boiler has its own built-in cut out for that, it's more that if say, the living room is nearly at temperature and is going to stop heating, but the upstairs bedroom thermostat is about to drop below its' threshold soon, does the tado system start the upstairs heat sooner so as to make use of the existing hot water in the system rather than needing to wait and reheat water in the system again in 15 mins time?

Assuming it isn't quite that smart yet, has anyone got any tips for how to set up scheduling or zones or something to reduce how often it happens when you have multiple radiators all with their own schedule/heat settings and heating/cooling different rooms at different rates?

All I can think of to do is to maybe zone off the common areas (kitchen, living room, hall) since they often have doors open between them anyway, and set the coldest spot sensor in that area (the hall) as the "master" for the zone, just set to a few degrees cooler than I'd want the other rooms to be.

I haven't done it yet because I'm lazy and don't want to do all that, see how it goes and have to do all the set up involved in rolling back, and I think, if I've understood the support articles properly, that if I did do that I wouldn't be able to use each radiator valve independently at all without affecting what the other radiators in that area were doing, right?

The dream is to use the Tado system as an interconnected "whole house" smart heating management system and individual room control.

Suggestions welcome :)

Unkledunkle

Well. This had been a rocky road.

Conclusion: I'm getting rid of my smart TRVs and putting dumb ones back on.

Turns out overlapping heat cycles was the least of my problems. Since no-one had any ideas for my post above I started looking back at my schedules manually to force them not to by adjusting timings instead.

But once I started looking at this and monitoring it closely it became obvious that the TRV pins do not always work (no audible noise, and no heat getting to the radiator at all for an hour or more) when calling for low heat.

Tado's only suggestion solution after a painful two weeks exchanging one written message a day because you can't call them has been that they'll hobble the system if I want so that the boiler never turns on for low heat calls.

Despite the number of threads I've found where someone has said Tado adjusted the range of motion on the valves, Tado had this to say to me (after 2 weeks of back and forth):

"We can do some tuning our end so that the Extension Kit won't call for heat unless there is a higher heat request. After the changes are made you have to test the system and check if it works as you like."

And

"We cannot influence the physical behaviour of the pin inside the Smart Radiator Thermostat. We can only modify some parameters of the algorithm the use so that they don't trigger the boiler when there is a low heat request."

...

Despite this thread:In what steps can the radiator valve regulate heat? And for the thermostat? - Page 2 — tado° Community (vanillacommunities.com)

And others which indicate they can in fact do this, and have adjusted firmware in the past to do this.

Plus I did some checking - the app makes it very laborious to do this - and turns out I was wrong: it hasn't saved me money. Tado as a central thermostat certainly did, but the smart TRVs have doubled my Kwh usage even with quite low temps on flow rate and each room thermostat - the house isn't heating higher than 19, ever, and generally I wanted it to sit at 18. Before i got the smart TRVs this actually worked pretty well.

Analogue TRVs are more reliable. Tado smart TRVs are best suited for ONLY rooms which are less well used and therefore only need burst heating.

Faith in Tado smart TRVs has completely collapsed now.

Unkledunkle

Update because it's not fair to leave this hanging since there was a change a week or so later, and I forgot all about it.

After more back and forth, it turned out they could in fact make some changes to get the smart TRVs to open more widely on lower heat requests. They put whatever this setting is to maximum.

This did not completely solve the problem, but it definitely lessened it for the next few weeks until the outside temps got cold enough that calling for low heat for any length of time became a pretty rare event anyway. We'll see how things go as it starts to warm up in the spring.

But a pretty maddening experience nonetheless. I have made some notes for myself for heating season build up/spring cool down around tweaking my room schedules to minimise any residual instances, so in case this helps anyone else with a multi room set up who has this kind of issue:

August:

Remove TRVs, change batteries, WD40 the valves and give them a wiggle. (I do this anyway)

Early heating/late heating season

I would characterise this as "Late sept>november, late feb>april"; or "warm enough outside that heat loss from my particular property is quite slow". In my case that's when outside temps range from ~8-16C.

Flow temp on boiler should already be very low from end of spring. Leave it there.

To limit how long a TRV can fail to open enough before it goes 'oops, call for moderate/high':

• During short scheduled heating periods (~2hrs) e.g. monday morning kitchen, run a 15 min slot at 2 degrees warmer than intended target for the remainder of the time. Good chance it'll hit warmer temp very fast, shut off and never need to call for heat again until you didn't want it anyway.
• During longer periods of heating, set 30 min intervals every 2 hours at 1 degree warmer than you want. The 2 hour blocks 1/2 degree colder than you want. Prior to the fix, I had to have those boost periods set to 15 mins at *hourly* intervals, which still used less gas than trusting the TRVs to maintain.

In my property, with the set up above, rooms set to 19 at max tend to quickly hit then keep rising a degree or so after the radiator valve shuts off, and during the 2 hr 'cooldown' periods. 17.5-18 period remains comfortable, and generally speaking we never need any room set higher than 18 to remain comfortable.

Mid heating season

"november>mid feb" or "cold enough outside that heat loss is noticeable almost as soon as the radiators cool". In my case that's the point at which the outside temps are not really cracking double digits ever.

~notch up the flow temp on boiler maybe 1/2 a notch (I have a frustrating 1-6 dial, each full notch is about 8-10C).

Less need to worry now as when rooms call for heat it tends to be quickly moderate or high anyway due to the rooms generally losing 1C per hour if heat's not getting put in.

Adjust the schedules as a result:

• 'Perceived comfort' level may have dropped simply because heat loss rate has accelerated rather than the heating struggling: set expectations 1 degree C higher, put a jumper on, see how you go.
• schedules don't need spike periods now, let the Tado maintain at a comfortable temperature.

In my property, with the set up above, rooms now tend to be set to 19-20 (north/south facing now makes a difference) when intended to be 'warm' with unoccupied set-backs at 15-17, and this works well. With the occasional hot water bottle or extra jumper in a cold snap, anyway.

Deep heating season

"Deepest December and January" or "If we're in, the heating's on. As well as jumpers. And possibly a hot water bottle too, especially if we've just come in."

Pretty sure at the moment that this is going to be as per the mid-heating season, but with the flow rate up another half a notch.

Hope that helps someone. Definitely considering alternative systems for this time next year though.

Unkledunkle

This thread is turning into something of a blog lol but if it helps anyone, great.

TL; DR

• If your boiler doesn't itself have weather compensation, then manually raise/lower the flow rate on your boiler as the seasons progress. You're looking to hit that sweet spot where there's no steam coming out your flue if the heating has been on for more than five mins or so.
• Early/late season: pick a flow rate that works for the warmest days and notch it up slightly on the colder ones.
• Mid seasons: flip that and set it for the coldest days and nudge it down on an unusually warm one.
• If your smart TRVs aren't reliable when it's warm outside, set your schedules to have short periods of slight over-heating, with periods in between slightly cooler than you'd want.

V long, read if you want :p

Putting aside this weeks little snow-based hiccup - this is how I've settled out on seasonal flow rates/schedules for my house, in order to compensate for the smart TRVs being unreliable (better than they were once Tado made their tweaks to the pin range of movement for low heat, but still not actually reliable) if it's mild or warm outside.

Target room temps:

• Comfort temperature. For me this means aiming to maintain 19-20C, assuming sensible clothing layers and judicious use of hot water bottles. The goal is not t shirts indoors in December, its comfortable temperatures that the boiler can hit/maintain whilst still condensing.
• Set backs/sleeping temperature is 16-17.5.

Note that two of our radiators simply aren't large enough - in the depths of winter getting higher than 19C can be impossible in those rooms so we don't bother trying: but we only know this thanks to Tado room graphs, so that is a definite win for Tado (always good to recognise the actual wins since I spend so much time moaning).

(My) Boiler flow rate settings based on season: 

• May-August heating off. Jumpers exist :p  
• Late Sept & early April: 2 (53C flow, 10C+ outside temps). 
• Oct, March: 2 (53C flow, 8-10C+ outside temp) 
• Nov, Feb 2.5 (55C flow, 2-8C outside temp)
• Dec-Jan 3.5 (61-65C, -2-6C outside temp)
• Extreme cold spells (sustained -3C and below temps): 5 is probably enough but will not be fully condensing as my radiators just can't deliver the heat fast enough. 

NB - manually turn up by 0.5 for a cold day or by 1 for a cold spell - e.g. right now in our snowy March week I'm back up to 3.

Room schedule changes by season: 

- late April- early Sept heating is off, call for heat on room by room basis using TRVs, if needed. 

- late Sept-Nov, March-early April: short (1/2 hour) comfort periods with set backs inbetween. I.e. a "spike" heating schedule to prevent Tado TRVs calling for low heat but not actually opening), . 

- Nov-Feb: just maintain "comfort" temps during our entire occupied periods with no need for spike heating <- TRVs basically reliable enough at this point to, well, rely on. Setbacks overnight/unoccupied. 

Again, hope that helps someone out there tying themselves in knots trying to work out what to do with their own system if it's lacking actual weather compensation or you have a lot of TRVs and you find some of them have your boiler firing for hours to no effect even after you've checked / addressed any sticky radiator valves.

hapklaar

Thank you for sharing your experiences in this thread. You unfortunately didn't get any reply in here, but the info is much appreciated!

Glasofruix

Very detailed info, thanks. I've also tried using smart TRVs as independant thermostats, but i've noticed quickly that it was more beneficial to leave almost every single one in "dumb" mode and just allow a couple of them to be able to actually call for heat. The overall temperature is stable across the rooms (10 rooms 8 smart TRVs) and since i use modulation the flow temp is not an issue.