Just a quick silly TRV question

[jjscruff]

I had 2 x smart TRVs and recently took advantage of the schneider sale and bought 6 more

The only thing is now i have so many independent radiators, it seems like the boiler is constantly on because the chances are at least one of them is asking for heat
Is this definitely an efficient system? Is there anything i can do to change it so they aren't all initiating the boiler so frequently?

Thanks

[njknh]

It might have been better to install the iTRVs in one room at a time and only move onto the next room once you are happy with the schedule settings and temperature offsets for the first room.

Synchronising temperature transitions across multiple rooms and/or setting the temperatures lower is about all you can do to improve efficiency. As far as I am aware there is no way of stopping the iRTVs from calling for heat - this is why I still have old mechanical TRVs in the spare bedroom, office, utility room etc. where comfort is less of a priority.

There are some tricks you can play ... even if the iTRVs are in separate rooms you can temporarily change their location in the Wiser app so that it thinks they are in the same room, so that it averages their temperature readings (or uses the Room thermostat readings if the room has one of those).

Unfortunately there is always a tradeoff between comfort and cost! Also where rooms are not well insulated from each other it doesnt always make sense to have them in separate zones.

I've only been using Wiser for a few months, other more experienced members here may have more helpful insights!

[PhilHornby]

You probably need to consider, what it is you'd like to achieve? (For me, it was "Control", "Comfort" and "Consistent/predictable temperatures" - hey, I should work in Marketing 😄). 

With iTRVs on virtually every radiator, I have occasions where a hulking great Oil Boiler fires into life just to heat the downstairs loo. That's probably the least efficient use of a non-modulating boiler, but at least it's not cold in there anymore - which is what I wanted. I even went as far as telling the system it has a Gas Boiler - so that it operates it more frequently. If it shortens the boiler life, then so be it...

If you have a Gas boiler, doing the opposite and setting it to Oil will reduce the maximum no. of firings per hour. (In my case it was nonsense anyway; I've turned the flow temperature down (as an experiment) and so the boiler does zillions of ON/OFFs for each one that Wiser thinks it's done).

Does your boiler support Opentherm? I believe the Wiser implementation is a bit broken at the moment, but when working, it should do a better job of matching the boiler output to the load.

Some thoughts, if nothing else 🙂

[jjscruff]

thanks for your replies

Could you advise how i can "Synchronising temperature transitions across multiple rooms"
I thought you'd be able to group the TRVs into separate channels or something but i can't see how you do this.

Cheers

[njknh]

Generally you set up Wiser schedules for each room that has a radiator and/or room thermostat using the Wiser app. You can use the same schedule for multiple rooms by selecting the rooms you want a schedule to apply to under Schedule Details, but this is probably not terribly useful because you will probably want different temperatures at different times in different rooms. If you had two bedrooms which were not well insulated from each other you could pretend that these were actually one room with two radiators when setting up Wiser - the system would then take the average of the two TRV temperatures and always call for heat in the two rooms at the same time (This is probably not terribly useful, but I'm just pointing out the things you can do).

I set the temperature to 14C at night then in the mornings turn on the heat. Initially I called for heat upstairs 30mins before calling for heat downstairs, but concluded that this was not very energy efficient and it was better to call for heat at the same time upstairs as downstairs. When I refered to syncronising temperature transitions I was just suggesting you synchronise the timings of temperature changes in the schedules for different rooms if you are trying to optimise efficiency.

There is a tradeoff between comfort and efficiency which is most likely going to be different for different users. At one stage I put iTRVs on every radiator and found, like you, that there was always some room calling for heat and the boiler was running a lot. I have ended up reverting to mechanical TRVs in some rooms - I don't for example want the downstairs toilet calling for heat if the window has been left open so this room has a mechanical TRV which cant call for heat, but that choice may not suit everyone.

[jjscruff]

debating whether to return the other 3 TRVs i ordered that i have yet to unpack
In order to stop individual TRVs from calling for heat non stop could you in theory stagger the schedule by setting a temp for all radiators in the morning for an hour or so, then turn them all off for a couple hours then on again every two hours? then they're all calling for heat at the same time?
I say "all" but i don't mean every one, just the main ones

[david101]

I'm guessing that at the moment you have every TRV in its own "room" but if you think of each room being a zone then you can group multiple TRV's into a single zone i.e. have a room/zone called downstairs or zone1 for example and add all the TRV's installed on the downstairs radiators to it. Similarly have a room/zone called bedrooms or zone2 and allocate all the bedroom TRV's to it. 

[jjscruff]

yes, how do i do that on the app??

[david101]

Create a room and call it Zone1 (for example), create a schedule for Zone1, then reallocate all the downstairs TRV’s to Zone1.  If you have a room thermostat then allocate it to Zone1 as well but don’t allocate two room thermostats to the same zone. Do the same for upstairs except in this example call it Zone2.

[jjscruff]

thanks this is v useful i didn't realise you could do this

Only way it could be improved is if you could still use the TRVs independently on occasions

[jjscruff]

another quick question if 3 TRVs are grouped under one room, which one does the room use for the temperature?

[PhilHornby]

I've never tried with three, but with two it uses the average of the pair. One might expect it to continue this approach for any additional iTrvs...

[david101]

My understanding is the same as PhilHornby. Personally if I was using the Wiser system in this way I would allocate a room thermostat to each room/zone so that the temperature is measured more accurately. Making sure that the room thermostats are optimally placed.