TRV Mode

I wonder whether anyone else would find this useful:

Problem: old leaky house that is unable to retain heat, potentially with mixed heating modes.

Second problem. How to make best use of a boiler firing when zone is not expecting it.

Solution: introduce 2 new modes for Smart TRVs - Passive and Passive Limited.

The idea would be that (for example on a cold night) the TRV would move to a passive mode. This would set the TRV to full open and in the case that another heating zone called for heat, then this TRV would benefit from the heat too. This is for bedrooms where there are several cold rooms but one that needs to stay at a steady temp (baby room) but the other kids rooms would benefit from the heat too.

In a passive (limited) mode, then the behaviour would be the same except that it would cap the temperature of the room. The trv would stay open until a specific temperature was reached and it would then close. This is essentially the same as a normal TRV.
Again this would be for bedrooms.

These passive behaviours would particularly benefit houses with mixed underfloor and radiator heating where the ufh needs to be on several hours before the radiators, but once the boiler is on, it may as well pump hot water to the radiators too, but the heating wouldn’t be on otherwise.
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  • I'd like this too, but not for the use cases you mention. As the TRVs are pretty noisy when opening/closing, I set my schedule to ensure my bedroom heating never goes on when we're likely to be in bed.

    But this results in a cold bedroom in the morning, and upon waking up I need to manually turn on the bedroom heating.

    With a "passive" mode, I could tell the bedroom to enter a "passive" on state when we go to bed, this would open the TRV, but the room wouldn't heat as all other zones would be off by this time. Then, at 5am when the other zones start calling for heat, as the bedroom valve would be open, it too would start heating and there wouldn't be any noise from the TRV!

  • @Rbbhghs Don't forget to vote for your idea by clicking the grey up arrow.

  • Nice use case also for the solution.
  • We have a similar situation. Old house (UK) with north facing rooms so they cool down faster but we don't need to explicitly have them at a set temperature all the time.

    But because they can cool down a lot they draw warmer air from the surrounding areas.

    I'd probably put them into "passive" mode when they are not being actively used so they benefit from active rooms.

    i'd also like them to follow a target or maximum temperature and close the valve to prevent over heating.

  • Yes please! I'm using two zones of one TRV each and a multi-room main zone from wall stat. All can call for heat, main zone always gets it and TRVs can shut down at temp. It'd be good for TRVs to preemptively open up a bit if temp is falling in their zone and another zone fires the boiler. Otherwise what can happen is main zone calls for heat, hits set point and shuts off then while system is still warm a TRV calls for heat (causing boiler to fire as system temp below boiler set temp) which reheat whole system and causes overshoot in main zone as well as wasting fuel.
  • jelockwood
    jelockwood ✭✭✭

    It took me a while to understand what was being requested but I now see the benefit.

    Since this does not involve any hardware changes a software enhancement like this even if it is somewhat counter intuitive is worthwhile.

    If the TRVs were quiet enough it would be less important. 💤

  • if you contact tado, they can stop the TRV from calling for heat, it will the act as you described 'Passive Limited' mode, you can set a max temp on the TVR via HomeKit or the Tado app, but it will NOT call for heat, But it is like this all the time, I have had my hall TRV like this for well over a year.

    I asked tado to allow users to do this within a schedule and he agreed it would be a great addition, and said they would look into adding it, But this was well over year ago, and still nothing..

  • Tado engineers were not able to made a chilld lock for valves in 4 years...let alone this relative complex feature...sorry, but support were teasing you, as usual.

  • Can Tado please enable an Open option on the radiator valves whereby they remain in the open position and is not controlled by any other device such as the wall smart thermostat?

  • This is also useful in multi-floor setups like mine. Right now I have four different TRVs in second floor (2x bedrooms, 1x office, 1x hallway) which open up and call independently for heat from the boiler. During the night I'd like to still be able to have either one of the bedrooms call for heat, but all four radiators up (so that the temperature at the floor is more even). Others have suggested marking a TRV as "INDEPENDENT", but evidently this doesn't work (during the morning I want the Office TRV to be able to call for heat).

    Ideally this "Open" option will be an additional parameter to temperature, which one can control through smart schedule as well.

  • This is a great idea in principal, and I can see how it can be useful in some scenarios, although each open valve adds to the thermal load on the heating system and correspondingly makes the boiler work harder - no such thing as a free lunch.

    To extend the idea a little, but significantly increase the complexity of the algorithm, the real wins come from "scavenging" heat at the end of a normal heating cycle, or to keep the boiler active when programs have short gaps between them. Pre-emptive opening of a valve in a room that is due to heat soon, whilst shutting down the boiler and just running the pump on to move the hot but now un-needed water through to cold or cooling radiators that will demand heat soon. I think this would effectively be the same as the action to OPEN without actively demanding heat, should be actively used by the system to maximise the use of available energy.

    This could be called "miser mode", and it's more advanced features like this that will ultimately boost the Eco credentials of the product.

    This would require more direct control of the boiler and pump demand mechanism on the boiler, since most boilers control pump behaviour. Interestingly, independent control of the pump and the boiler are also key to good temperature management if you don't have TRVs installed and are relying on a more traditional thermostat control only for room temperature management.

  • Please don't make things too complicated. Tado system does not have a close control of the boiler. It acts as a thermostat retuning the ambiant and target temperature of the room that call for heat.

    By using the planning and the boiler advanced settings I can stop the pump while the rooms temp are above target temp.

    For cold rooms that does not need accurate temp control I disabled the heat calling feature.

  • mperedim
    edited February 19

    There are quite a few requests that are analogous to adding a TRV mode (basically allow moving the radiator valve without asking for heat). In no particular order:

    • An ‘On’ function for the Smart Radiator Thermostats
    • Preventing radiator valves from getting stuck
    • Smart Radiator summer / maintenance / bleeding mode (leaving the radiator open)
    • Pretty much all the use cases listed here
    • Pretty sure there were similar asks in the "Big ideas archive"

    Bunch of people have mentioned that you can set a TRV as "independent" but that can't address all use cases, especially if one considers that one cannot make the TRV zone membership part of a smart schedule.

    Ideally "call for heat" and "TRV position (open/closed)" should be too orthogonal things. This will for sure add some complexity (maybe it can be an advanced setting hidden by default?) but it is a very useful feature.

  • Passive mode is a great idea! I would like some rooms heated if the the heating is on anyway but only at certain time of the day. Other times I would like the TRV to be able to call for heat
  • Bob20
    edited May 25
    Yes, this would be a great feature and it should also create savings.
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