Does a wireless TRV bring the boiler on?

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As part of a whole house smart heating system, if a wireless TRV calls for heat will it cause the boiler to come on?

That's the only benefit I can think off, but reading some of the systems it seems that the boiler would need to be activated by the main thermostat/controller first.
 
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It all depends on the wireless/smart TRV. Most of them that I'm aware of are connected in some way to a controller which in turn connects to the boiler via some means.

Rather a vague answer but yes the TRV would usually result in the boiler firing up (assuming the TRV was opening up/calling for heat)
 
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I've been having a look at a few, and the info is a bit vague, but none seem to state specifically that the TRV will bring the boiler on, but they do mention that the valves can be controlled wirelessly once the boiler is on.
 
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You might like to ask in Plumbing where there are a few Evohome installers.

That system certainly has a connection to the boiler, and I have always assumed that it is influenced by both time and temperature.
 
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I have the evo home, and if any TRV senses the temp below what its set to then it sends the information back to the controller which then sends a call for heat via a relay connected to the boiler. How the boiler gets the call for heat isn't that important but most/all the smart TRV's I've known/read up on will in someway get the boiler to fire up (rules depending)

woody, do you have any specific TRV's that you have been looking at that would like more info on how it integrates with boilers?
 
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woody, do you have any specific TRV's that you have been looking at that would like more info on how it integrates with boilers?

I have looked at smart heating controllers along the likes of Nest and Hive etc, but I don't see the advantage of these on their own, unless there are just one or two people in the home and they have irregular comings and goings.

But what would be useful, would be for individual radiators in some of the bedrooms to be able to call for heat as and when required, rather than waiting for the main thermostat downstairs to trip on. I can see this as being effectively like having several zones on the one system.

Now, I've not researched this extensively yet, but it does seem that the makers of these TRV's promote the "usefulness" of wireless setting and control from a smart phone, but say little or nothing about an individual TRV's ability to actually bring the boiler on.

So it's this function that I would be interested in, and it would make me consider a smart controller like say Nest, if TRV's could be connected to it to effectively perform the controlling function.
 
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Honeywell Evohome does exactly this, individual room control. Each TRV (or individual room thermostats) will work independently to maintain their set temps and all communicate with a central controller.

Other smart heating like nest are typically single zone with a single room thermostat HOWEVER with some of these you can add on additional smart TRV's like the energenie which communicate with the nest (although how this works hasn't been included in the reviews I have seen) so this can give you some kind of multi zone control.

EDIT: Unless the smart/wireless TRV states it controls the boiler, or integrates with something like Nest, Hive etc... I would assume it simple opens/closes that valve regardless of a call for heat or not at the boiler.
 
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I have fitted two MiHome eTRV's and not that impressed, it is not the eTRV at fault, it is down to house design. Nest will work with the MiHome eTRV with a follow command so works similar but not as good as the EvoHome. Well it's hard to say if the MiHome is not as good as new apps are being released all the time, it is an ITTT device.

The basic idea is a eTRV gradually alters the water flow so it is not digital i.e. on/off, but analogue slowly opening or closing the valve, with a condensate type boiler the flame height varies according to return water temperature so during the heart of Winter it will auto adjust output to suit the eTRV demand, the anti-cycle software of the boiler should in theory mean even as the weather warms up, it should still control the rooms at the set temperature.

However there are two problems, one is as summer arrives the boiler would still need to fire up every so often to find if there is a demand for heat, and two when the valve alters the set temperature if the boiler is off then nothing happens.

Taking number two first, I found the time switch can be used to over come this problem, I wanted the temperature to raise at 7 am so I set time switch to switch off boiler at 6 am and back on at 7 am this means the boiler is nearly always running when the temperature set point changes, that worked well.

To stop it firing up in summer you need a wall thermostat, set at a temperature above that of the eTRV, theory OK, room thermostat set to 20°C and eTRV set at 19°C and only on a warm day will the thermostat activate. However it would seem with the follow command with Nest the eTRV and Nest are set to same temperature, so it needs some very careful positioning of Nest to ensure the eTRV works before Nest.

At the moment I am a TRV short, so as yet not fitted Nest, just the two eTRV's down stairs, and the hall has a standard wall mounted thermostat, in theory the two rooms should be independent of hall temperature unless doors left open, so mum is in rest bite so her room set at 12°C and door shut, current temperature 18°C, garage temperature 13.2°C and outside 14°C and the room has been set to 12°C for three days. So in theory it should be no warmer than 14°C, so why is it at 18°C?

Radiator should be stone cold, however it feels neither hot or cold it is hand temperature, but the rails of the stair lift are cold to touch, so clearly even set to 12°C it is still getting some heat, every radiator in the house feels the same, just look warm, now the instructions do say about fitting a coin between the pin and activator if they don't turn off, so maybe it needs that fitting? Having fitted the coin the valve has opened and closed so don't really know if working correct as the radiator has warmed up due to re-fitting the valve. Current room temperature is shown as 21°C.

If and that is a big if, the reason the radiator was tepid is because it needed the extra spacer (1p) fitting then may be now it will work? However I had followed the instructions so it should not have needed a coin spacer. And they have not worked as expected, OK reason was the house has a bay window, and the morning sun hits that bay window and the living room temperature can easy hit 26°C even in the winter, but cloud cover and the room can get rather cool, the other room also has a problem due to wind direction, the room still has a chimney and compared with hall where the wall thermostat is it can get rather cold. The better control of the eTRV has improved the general temperature control of the room. The eTRV were fitted because I had control problems, not simply a whim, so it is understandable that the room is still not perfect.

Until today I blamed the room getting too warm on the heat retained in the fabric of the building. And to be frank that must be part to blame, as with the central heating off completely, (due to an error) in heart of winter, it was some 6 hours later that I realised the room was a little on the cold side, and also it does not matter if the target temperature is 19°C and actual is 17°C if the main thermostat has switched off the boiler it will never warm up.

The hall temperature is a real problem, the kitchen and wet room lead onto the hall, both have independent heating, so hall can get too hot for boiler to run. In my own house, up to now talking about mothers house, in my own house it was designed to be heated with a single central gas fire, it is an open plan and up stairs can get really hot, but the Myson radiator circulates the air, so as long as bedroom doors are kept closed it works well from a single central thermostat. Bedroom temperatures are limited with standard TRV's so it has worked A1 for years. No need or point in fitting eTRV's it simply does not need them. Also the boiler is old, so no option boiler will switch on and off, it does not vary flame height.

So really I need to look again tomorrow, and see if mothers bed room is cold at 12°C if so then the other room also needs a 1p spacer fitting. It must have been nearly fully closing the valve as radiator only tepid, but until mother was not in the house I had no need to set so low, so thought tepid was correct, only today when room unused for such a long time did I realise there was a small problem.
 
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An update, the eTRV with penny in now gets the radiator stone cold, seems the MiHome eTRV and Honeywell valve did not quite match, 2 mm spacer fitted as per instructions, without it the nut would go past the threads on the valve, seems I need to now do it with the other valve. First I want to try heating the room again and ensure the radiator will also turn on fully as well.

Further update the penny moved and jammed the valve closed, now removed again, you can get Valve pin extender spacers however not listed at Screwfix.
MIHO013-PES.jpg
I am going to try again without spacers as added an extra TRV to system, if still having problems will need to find a supplier.
 
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If you simply had wireless TRVs connected to some controller, all they are doing is saving you the effort of walking around the house turning the TRVs on/off! Clearly they can't magically turn the boiler on/off, unless you run your CH on at all times. (I don't know if with smart TRVs, doing that is efficient?)

So to get the CH to also come on/off as needed your smart system needs to replace your pre-existing controller unit, which I imagine most do. But is a bit more work to install. When I looked at EvoHome it seemed both options are available so if you just want smart TRVs working with your existing programmed thermostat/controller this is possible.
 
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OpenTRV does control the boiler - optionally. If you install it, they have a receiver that listens to the transmissions from the TRVs, and closes a relay to fire the boiler if any of the TRVs is calling for heat. What you don't get with OpenTRV is the remote controllability as it's not the market they were aiming for. It is all open though if you wanted to start hacking.
as Woody hints at, it's rather half doing a job badly if you still need other (inferior) controls (timer, room stat) to bodge the system to work.
 
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I would think any eTRV which has two way coms could be made to control the boiler? My eTRV's show on the web page target and current temperature and I can change the target, so the eTRV has the ability.

However some where there needs to be a hardware device which takes this info and uses it to switch boiler on and off, now MiHome will connect to Nest, but it seems from what I read there is only a one way connection at this time, Nest can tell MiHome what temperature to go to, but MiHome can't tell Nest it needs the boiler switched on.

However the interconnection is know as ITTT or If This Then That and it consists of Apps written to join devices, so in the future, or maybe even now, some one may have written an app to allow the eTRV to tell the Nest to turn on. Since I have MiHome I have access to MiHome apps
but as yet I don't have Nest so don't have access to Nest apps. So for all I know you may be able to have Nest follow MiHome rather than MiHome following Nest?
 
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Up date, as time has passed so the apps available have increased, plus I have been directed to some third party systems to control example here after fitting a standard TRV in the hall with the wall thermostat, the house seems to work well, a real hopscotch of a system as used what has been left over after failed attempts in the past, using two wall thermostats hall main one but also one in kitchen used over night to both stop the temperature over night going too low and give a boost in morning.

However it works now, so leaving well alone. It does annoy me to think I bought eTRV with wifi and as running now wifi not required, so could have used cheaper versions, but that's life.
 
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Given to understand that Nest's default premise isn't ideal for "one or two people with irregular comings and goings" as the idea is you just turn the knob up when you get home and down when you go out, eat learns your schedule and how hot you like the house, measures the delay between calling for heat and seeing heat and can then control things automatically so your house is as hot as you like it, on your schedule

If you don't have a schedule that kinda goes out the window. Nest is controllable remotely so you'd have to use that to control if tour life was irregular
 
D

Doggit

I think that Nest and Hive, are techie solutions to a problem that doesn't really exist, but they'll always try and make you think you need the latest gadget.

The eTrvs are linked to a controller, that connects to the boiler, and will replicate the room stat, and the time programs There is an inherrant assumption that the heat is required for the house, and you need different temperatures in different rooms, so in some cases, a room will call for heat, but in most, the heat is being removed because that room isn't being used. If someone wants the room very hot, then the controller will set the overall system to the highest temperature, and then reduce if for the other rooms in turn.

With Hive and Nest, the controller will link into the home router, but I'm not sure how the app accesses the router.
 

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