Hot water monitoring & Tado hot water tank thermostat

Sounds like a fault that needs troubleshooting.

I wouldn’t expect them to be helpful. It needs troubleshooting on site.

@Jurian thanks for responding, and I think your second explanation about market size for certain features is helpful in some respects for context (not just applicable to this thread too).

I would phrase this in a slightly different way, which may be something that can be considered by Tado:

The TH10 device I mention above is a plug-in external temperature probe and a device capable of reading the temperature probe and switching a live feed. The cost of the whole kit is around £18, you can buy the probe on it's own for £3-£4, and the device is £15 or so without the probe. Clearly, the component parts (A2D chips and supporting physical seocket) required to read the probe (which seems to be a generic part with a jack plug connection) are a few $$$ or less from a production cost perspective.

Would it not then perhaps make sense for Tado to include the temperature reading function (hardware and software) and a jack plug on the receiver so that the end-user could choose to plug in a temperature probe and read their tank temperature and display it in the app ? From there it's a short step to making the hot water schedule capable of using that temperature too, allowing scheduling that either maintains water at a preferred temperature, or simply shuts off demand once the temperature is reached (modern well-insulated hot water stores lose temperature much more slowly than rooms do unless water is being drawn down).

Even for markets outside the UK, a lot of Smart tech such as Tado is as much about comfort and convenience as it is about saving money or the planet generally. Knowing that there is plenty of hot water or no hot water before you jump into the shower is a real positive, especially if you live in a house with several others. Being able to specifically heat the water and run a maintenance program for it at peak usage times (like morning or evening showering) is a convenience that may have a smaller market than regions with shared domestic heating services where the heat is "free" or "all you can eat" rather than the UK model, but even in that situation, being confident of the situation before getting an accidental cold shower has merit.

For the UK market, there is a secondary health and safety consideration that may add value to the feature. Defending domestic hot water systems from legionnaires bacteria requires water stores to be able to heat to more than 50^ reliably, which is at the limits of "scalding" for most people. Being able to check tank temperature is routinely exceeding that level is a secondary but real benefit.

I'll find a little time over the weekend to respond fully, thanks @Jurian

One other thing to add on the general topic of Hot Water:

When you turn on the HW demand (manually or by a schedule), you are verly likely to make a massive impact to the CH performance. This is for a couple of reasons:

1. Your flow and return heating water circuit is probably all on 22mm copper (or plastic), but each radiator drop will be 15mm or 10mm and flow through each radiator is restricted (balanced) by the lockshield valve, regardless of how open the TRV/SRV actually is. Your HW heating water circuit through the hot tank heating coil is probably 22mm all the way from the boiler, through the solenoid, heating coil and back to the boiler with nothing to choke or resist the flow. When you turn on the HW heating (open the HW solenoid) then almost all the boiler feed water will prefer to run through your HW tank coil, not through your more resistive radiator circuits. This means that the radiators almost immediately start to cool and will continue to do so as long as you're heating the water tank.
2. Your hot water tank is an energy store. The bigger it is, the more energy is needed to heat it through 1^C. When the tank is cool or cold, the boiler feed water may enter the coil at 70^C but the tank will suck that heat out and the exit from the tank coil can be massively lower in temperature on the return side, meaning the boiler needs to burn a lot of gas to reheat the circulating water feed whilst the tank heats up.

Basically, this means that the better insulated your hot tank, and the pipework around it and running to/from the boiler (to all of your radiators too) then the better, from an economy and a heating performance perspective. It also means that the way you programme your water heating can make a significant difference to your comfort generally, and to your perception of the performance of the system.

I have two water stores, 120L and 150L, so around 275L all told. The smaller tank feeds the kitchen and downstairs shower/bathroom. We don't use the shower much, but obviously during the day, we use the bathroom regularly and we run the kitchen sink. I reheat this tank for short periods through the day, to maintain a tank temperature of between 60^C and 65^C. Maintaining a higher temperature means that the boiler isn't doing too much work, and I am only needing to raise a comparatively small tank volume a few degrees in each cycle. 15 minute dips in the ability of the CH to maintain isn't too onerous or noticeable most days.

The 150L tank feeds the utility room, the house and en-suite bathrooms, which also have showers. As a family we mostly shower in the morning when we get up or in the evening after work. The tank is heated to full temperature (around 65^C) in the small hours when a prolonged period of hard heating isn't impacting the house comfort (typically between 0300hrs and 0500hrs). The tank gets well used when we get up and cools significantly first thing in the morning, but I reheat it in bursts of 10 minutes after 0900hrs after the heating has reached proper temperature and has started maintaining the room comfort. This moves the tank temperature back to usable by early evening and I don't care if it gets heavily used because overnight it'll get it heated again.

Since both tanks are new and well insulated, they don't lose temperature too quickly, so the intermittent heating doesn't really cost much more than a single burst, but my comfort levels overall are much better. Using two separate smaller tanks allows me to manage the HW demands of the house more efficiently.

I hope this helps others to understand the impact of HW heating and one method of mitigating some of the impact and reducing the costs.

Hi all,

I have noticed a similar issue with my installation and during my search, I found this topic that I think it's related to the problem.

I have an S-Plan installation, tado controller for hot water and also controlling 2 zones. My boiler has entered in safe mode twice already because of the hot water feature. I have the hot water scheduled to come up twice a day for 1.5 hours. On both times the boiler entered in safe mode was when the hot water schedule was ON.

So, in my case, my water tank has one of those temp sensors that you put the temperature you want for the water and if the tank reaches that temperature it shuts the valve. And I think this is the issue that I faced on these 2 occasions, the hot water kicked in on the schedule, during that schedule the water reached the temperature and the sensor shut down the hot water valve, but Tado never knows about that so the boiler continues to run, since during that time no other valves opened the boiler detects that and that's why boiler stopped working and showing flashing lights (safe mode).

Is this the normal behaviour, or am I missing something here?

I do have a thermostat displaying my hot water temperature, right next to my Tado controller. We have water solar panel controller. It would be great if the wire used to sense the water temperate of the boiler in the solar panel controller could also be used and read by the Tado controller, unfortunately the solar panel controller does not have an app.. its to old!

I am in agreement with XKRMonkey and Ben_UK, it would be great to control the temperature of the hot water tank. It does seem very inefficient heating the hot water to the stat temperature if you only want to wash your hands. May be my heating system is not your average, with a solar panel and wood burning stove supplying heat to the heat store, but I know many more people with this type of heating than AC. If I know that I’m going it get the hot water heated from the solar panel during the day, I don’t want the boiler coming on, and the same goes for at night with the wood burner. So being able to set the lowest temperature of the heat store before the boiler comes on is a big saving.

As said the easy work around is to use a Sonoff TH16, and it is probably cheaper, but this means you need two apps and it does make the Tado not quite as smart. My Tado app is telling me I have saved 100% with Tado this month, but sadly my smart meter does lie!

May be it just costs too much to add this, but could the AC controller be modified to perform this function.

I fail to see why this is so complex.

The tank thermostat is only the same as the wall thermostat in its operation, with radio connectivity to the tado controller. Simply put strapping a wall thermostat to the tank would probably work (but not advised)

The electronics would be identical with the exception of requiring a thermal probe to the side of the tank.

I am sure there will be disagreement, please tell me why this would not work.