Wired thermostat & Radiator valves
And I set up a nice schedule with thermostat(living room) and radiator valve ( bedroom-I know this one doesn’t make sense, the valve is not even installed) however during the night all the radiators were on. (Even though the living room was 1,5 degrees hotter than the current setting, and bedroom was 0,2) any idea what the problem might be? Otherwise Tado is not helping me save much at the moment.
Answers
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At 0.2 C over setpoint quite possible the bedroom unmounted SRV is calling for heat, they do that to ensure some overshoot and prevent boiler frequent switch on.
All radiators will switch on if you are on a single zone whenever either of them are calling for heat. The downstairs is hotter because the SRV is controlling the heat.
suggest you put manual TRVS or Tado TRVS (SRTs) on your remaining radiators.
Yes afraid you need a TRV body to mount a smart radiator valve on, it’s completely different technology to a manual radiator balancing or isolation valve.
You are not the first to make these assumptions.
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So one radiator valve can overrule main thermostat setting and can call the heat ( which in my case to whole apartment)
In that case, if I’m gonna mount the valves, I have to do it to all? Otherwise if one calls heat, the ones without Tado valves will heat up as well?1 -
@Sonert if you change the TRV configuration to independent then they cannot request heat from the boiler. They will simply limit the maximum temperature in the room. If all TRVs are independent then the main thermostat is effectively the master control.
Tado thermostats (like other smart thermostats) use TPI algorithms to maintain the room temperature. They effectively calculate how many minutes in the hour the heat source needs to be on to maintain a set temperature in the room. This may mean when the thermostat switches on/off does not coincide with the temperature going above/below the set temperature. This is more efficient than dumb thermostats which blindly switch on and off. Also, remember it will take time for Tado to learn the characteristics of your heating system.
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@Sonert I think a lot of people either buy for all rads or decide which rooms they want total control over. Total control means you control place the SRV in non independent and either accept the other rads will heat or you can add manual TRVS to cap those also. Running independent for me is a waste of functionality, if you system is not well a balanced like most then the room sits below your setpoint and the expensive Tado just acts as a rather expensive manual TRV. Either way sounds like you need to add a few more manual TRV bodies to your rads if you want the most from the Tado TRVS.
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@Hunter I actually find independent SRTs to improve system efficiency. There is no functional loss for me.
I have nine rads, with eight Tado SRTs. The smart wired thermostat is in the hall, with the bypass radiator. I don't particularly want it to demand heat - I.e. I don't want the boiler to fire up just because the hall is a tiny bit colder than set temp. It also has enormous thermal inertia - very slow to warm, very slow to cool - so a really bad option for regulating heat to the rest of the house. It is set to 18C (as a backstop) day and night. It could as easily be set to frost protection.
The lounge is the only room connected to the zone controller and the only room (ignoring the hall) that can fire the boiler. Typically, when the lounge is needing heat and turns the boiler on there will be several other rooms also ready for some heat, with SRTs open and able to take water. With several rads in operation at once the 9 kW output (range rated maximum) from my boiler can be spread amongst them, where the heat can be dispersed to the house rather than getting "stuck" trying to escape from a single radiator into a single room. This keeps return temperature low and efficiency high. It also prevents the boiler short cycling.
In contrast, consider the same system with every room connected to the zone controller and able to fire the boiler. Let's say the box room is a bit chilly and fires up the boiler. No other rads need heating at the time and my boiler is trying to force 9 kW out of a tiny single panel rad. Flow temp hits limit and the boiler shuts off, with a five minute pump overrun and a possible anti-cycling lockout for a few more minutes. The rest of the house is cooling.
Now another room cools too far and fires the boiler. Maybe it is also the only room to need heat at this time. Repeat the previous cycle. Maybe two or three rooms need heat. Not so bad, but still not ideal.
Furthermore, do I really want the boiler to fire up for a single room, especially the box room or second (unused) bedroom - in the middle of the day? No. Those rooms can wait until there is more serious work to be done.
IMHO firing up the boiler on the whim of individual rooms is a bad idea. It is not efficient (for a combi at least). I did actually set all my rooms as connected a few days ago. Gas consumption rocketed that day. It was a disaster.
I'm now back to one room controlling things. Yes, other rooms may drop below set temp a bit, but I'm trying to heat the whole house, not individual rooms one by one. The only rooms I really care about are the lounge (20C) during the day and the master bedroom (18C) overnight. Other adjacent rooms have corresponding temperatures set, not so much because I want them at those temps, but in order to share the heating load and not leave cold walls, cold spots and temperature gradients within the home.
This is along the lines of heat pump strategy - heat the HOUSE - and let the rooms all help each other to keep warm. Micro-zoning individual rooms is not recommended (see Heat Geek on YouTube), and in my opinion neither is micro-heating them. I may not be an expert, but my heating bills are kept very well in check, without sacrificing comfort. Just the opposite in fact.
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@eezytiger could you not have a achieved all the above with a few Tados and the rest manual TRVS, most of the time your Tados are not doing anything?
I have only 1 SRV that is not paired with an external temperature sensor, it’s independent because it seems to call for heat a lot and not operate in the same way as the paired SRVs, that coupled with the variable temperature offset makes them an expensive nightmare. It sits on independent registering the wrong temperature keeping the room kinda in the region of the requirement.
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Manual valves are imprecise and cannot be altered to suit a schedule. Plus, they don't feed back temperatures in each room to a single app.
I had manual valves prior to Tado. They were old (33 years old) and not one of them had any thermostatic control remaining. They had become wheelhead valves in the shape of TRVs. Presumably the Thermostatic pin control had somehow seized, leaving only manual guesswork as to how far open the valve was. My options were to replace them all with new manual TRVs or to go "smart". As a technofile I decided to go smart.
Also, when I bought a complete Tado system I did not know what I know now. But, even with the experience I've gained, I would not wish to swap out my Tado SRTs for manual valves. However, I'm much smarter than Tado, so I've manipulated the system to maximise operational performance.
So the Tado SRTs are all doing something useful. They are controlling temps with relatively high precision and accuracy, to a schedule, and reporting the temps and heating needs back to me.
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@eezytiger I have SRVs to solve an issue of variable demands throughout the day, having struggled with hive TRVS, TADO SRVs have met my requirements. That said I am also a believer in something that many heat engineers say and that is you should only really need a single thermo stat in a well balanced heating system that has been designed correctly with heat calculations. I live in a new build initially I could not get a room up to temp despite balance adjustments, a larger rad (probably a mistake)was added and the thermostat moved. That room is missing some insulation it heats up from solar gain and drops in temp quickly. The rad now has high thermal inertia. The other main room is super insulated but gets little Solar gain. So it’s a bit of a heat balancing headache. That’s why zoning was the way to go for me.
my view however remains that the vast majority of people are buying huge amounts of SRVs at massive cost and should not really need them and some may never even use them. Maybe I should buy some Tado shares if when they float.
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@Hunter When I say "micro-zoning" I mean setting unique and distinct temperatures for each room. For example, I used to turn some rooms off entirely, such as spare bedrooms or the rarely used dining room, keeping doors closed and letting them go cold. Or maybe I'd set a lower temperature for these rooms, such as 16C.
But this leaves cold walls and doors adjacent to rooms you are trying to heat fully, almost as though you've added a further "external" wall. So rather than fiddle about with unique temperatures for individual rooms I simply set the whole house to 18C for all rooms, 24x7, and just have a small bump up to 20C downstairs (all rooms) and in the bathroom during the day.
By putting the lounge in charge of the boiler I can make sure that I reach my 20C target for comfort during the day. The kitchen and dining room are simply included so that they can contribute to the lounge rather than leach heat away. The bathroom is a tricky one. I'd be happy with 18C, along with the rest of upstairs, so I only give it a bump to satisfy wifey. I mean, why heat it all day long when it is only used for a few minutes. But it can't force the boiler on. It just takes left over scraps when the lounge is heating anyway. It is more than sufficient.
Also, the system I have in place means that heating and cooling cycles are synchronised throughout the house. All rooms warm together, all rooms cool together. It's a coordinated effort. Much better than individual rooms shooting off at random. But fine and responsive thermostatic control by Tado SRTs means that no heat is wasted on rooms that don't need it. It's all very harmonious.
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@eezytiger I understand, it’s early days for me with this Tado, I won’t reach your state of harmony as I can’t justify converting upstairs so my system will always be a hybrid of hive and Tado. Currently my set up allows me to regulate a general room by room temp if required but really I only create a microzone by a few degrees in the evening. With my house being build recently my bills are lower than the norm and I am mainly chasing efficiencies which won’t be recognised. My house will not drop below 17-18 at night in deepest winter without heating but hey it’s interesting. Now I need to get this min burn time extended. I saw a post where others had also got there’s increased even beyond 10…..can’t help but agree that Tado doesn’t seem sympathetic or have fully considered boiler design.
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@Hunter I think a minimum burn time of ten minutes is enough. That's what I now have.
But my boiler can run continuously for much longer if the need is there. For example, mine ran non-stop this morning for 35 minutes from 07:00 in the attempt to raise downstairs (and the bathroom) by 2C. It only stopped then because the flow temp reached the set the 50C maximum (+2C overshoot) and the boiler made the decision, not Tado. I have seen it run for forty minutes straight in the past.
The problem with extending minimum burn beyond ten minutes is when the milder weather returns and a ten minute burn would be excessive. So be careful what you wish for.
The extended minimum is beneficial to me (for now) because I have limited my boiler to 9 kW output. If I let it operate at full power (24 kW) then, sure, it would modulate down when needed, but it would put out way more heat in ten minutes than it does now. In fact, if I did open the taps on the boiler to show the full output, a 3-4 minute burn might be sufficient. 3 minutes at 24 kW is not so different from 10 minutes at 9 kW. Similar energy output, but just at a different rate of delivery.
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@eezytiger I have a vailliant system boiler 18kw. It’s has turn down to 5kw so I tend not to go out on max flow temperature during any of these low delta from set control scenarios. In the morning I am sure the boiler will fire and run for very long periods as long as the return temp remains sufficiently low and the turndown is respected. Also during these longer periods as long as TADO keeps demand, the pump will still run and the boiler will reignite when the flow temp drops due to heat dissipating either due to temp drop in the rads or end of anti cycle time. As I am sure you know boilers take time to spin up and then reach temp, if they can’t get adequate rise in temp on the return due to low flow they will not rise in flow temp and stay at about 20 C delta. So sometimes with the short demands flow temps will be lower than set point and flow into the rad is low. Increasing run time will allow the flow temp to increase as the return temp climbs and more cumulative heat into the rad and hopefully close my gap with running further cycles.
If the run time to over extended I expect that I will see overshoot unless the controller takes the system out of wave 1 to compensate.
I will have to wait for the 2 day tado response cycle to see if they will change.
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@eezytiger thanks for your explanation (12.30h), this was the missing link in my comprehension of how Tado works !
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| IMHO firing up the boiler on the whim of individual rooms is a bad idea. It is not efficient (for a combi at least). I did actually set all my rooms as connected a few days ago. Gas consumption rocketed that day. It was a disaster.
This is why I want full control over the system, so the individual rooms can dynamically be batched... But I'll just have to settle for doing this by hand, it seems.
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