Getting a smart heating (Tado): Dynamic Valves? How important is the type of TRV?

[louis_b]

Hi,

I'm getting a Tado smart heating system (have a gas combi boiler). I don't have TRVs currently, so I need to get a plumber to replace my old valves and get TRVs everywhere. So I might as well get good ones, and it doesn't really matter whether one costs €15 or €25.

I found the Danfoss Dynamic Valves, RA-DV (link), which seem to be the latest technology. I think they have the standard Danfoss RA coupling, so mechanically they should fit (Tado comes with an adapter)? But does Tado work with this kind of Dynamic Valves? I am going to ask their support too, but I wanted to get community input too.

The house has an old combi gas boiler, where the pressure can fluctuate quite a bit. I am not a plumber, but I am thinking those dynamic valves could make a difference? Otherwise, Tado's valve calibration would go off, if the pressure changes?

Alternatively, I'm thinking of getting Drayton TRVs, RT212, RT313 or RT414 (link). The 212 and 313 are the cheapest with a "low cost wax sensor" whereas the 414 has an "accurate liquid-filled sensor". They also have the TRV4, with an even better sensor / energy efficiency. But I am wondering, are those differences actually in the valve, or are they in the "plastic head" that you screw on? Because as you know, for Tado, only the valve matters, because the Tado unit gets screwed on, and you "throw away" the "head unit" (sorry if I am using wrong terminology). Are the actual valves the same, so I can get the 212, or do I get anything by buying the more expensive 414/TRV4?

Thanks a lot for any help and input!

 

[Ben-gee]

In a standard trv the wax/liquid sensor is in the head - this operates on a pin in the valve body.

So no point spending more on a fancy head if you’re going to bin it!

 

[louis_b]

In a standard trv the wax/liquid sensor is in the head - this operates on a pin in the valve body.

Ok I see, that's good to know, thank you!

Which leaves the question of the dynamic valves (like the Danfoss RA-DV): That functionality is actually in the valve, not in the head. Would that work with / be beneficial to a smart heating system like Tado?

Also a slightly unrelated question: Can you buy just the TRV valves, without the head? A plumber told me they always come with the head, and if you install Tado, you'd just throw away (or sell on ebay) the heads. That seems quite silly to me and I have a hard time believing that you can't buy the valves without the heads? I checked Screwfix and googled a bit but all shops indeed seem to sell them only with the heads. But surely a plumber can get just the valves?

 

[Dan1990]

The Tado supplied adapters are plastic and have a reputation for popping off. Have not used them myself but I can see that they’re not very robust. If you purchase a TRV with an M30 x 1.5 mm thread you won’t need to use an adapter.

There are lots of complaints from users (including myself) that the vertically mounted TRVs do not work very well because they are affected by the temperature of the radiator. Tado’s solution was to produce a wall mounted temperature sensor that actually costs more than the TRV. Users with horizontal TRVs don’t appear to have the problem, so some people are rotating the TRV body as a solution. As you don’t have any TRVs already then probably wise to start with a horizontal mount.

Tado have an online list of compatible valves.

https://tado-hc-downloads.s3-eu-wes...ator_Thermostat-Compatibility_Guide-EN-V1.pdf

 

[king of pipes]

Ok I see, that's good to know, thank you!

Which leaves the question of the dynamic valves (like the Danfoss RA-DV): That functionality is actually in the valve, not in the head. Would that work with / be beneficial to a smart heating system like Tado?

Also a slightly unrelated question: Can you buy just the TRV valves, without the head? A plumber told me they always come with the head, and if you install Tado, you'd just throw away (or sell on ebay) the heads. That seems quite silly to me and I have a hard time believing that you can't buy the valves without the heads? I checked Screwfix and googled a bit but all shops indeed seem to sell them only with the heads. But surely a plumber can get just the valves?

You can get them if you know where to look

 

[louis_b]

The Tado supplied adapters are plastic and have a reputation for popping off

That's good to know, thank you. Might be an argument for the Drayton RT212 then. Any point then to go for the RT313 or RT414, or is the valve exactly the same, and only the head is different?

vertically mounted TRVs do not work very well because they are affected by the temperature of the radiator.

Good to know as well, thanks. My valves are at the bottom of the radiator so I think horizontally mounted will look more ugly / take more space, but it may be a good idea to still do it horizontally.
(PS: The wall temperature sensors were on sale recently for around £43, which I thought was okay-ish.)

Tado have an online list of compatible valves.

Yes I know, I mentioned and linked that list in my original post. As I said, the Danfoss RA-DV are not on that list, but according to Danfoss they have their standard RA connection (which are on the RAS-C2 too, which are supported by Tado - with adapter though). I am a bit suspicious though because on pictures, the RA-DV connection to the head looks different to the one on the RA-N.
The fact that they're not on the list doesn't necessarily mean they're not supported, the RA-DV are fairly new, uncommon, and pricy valves, so it would make sense that they're not on a list of most common valves.
My question was more about from a plumber's perspective: Are those dynamic valves something worth having, and does that mechanism play well with a smart heating system?

You can get them if you know where to look

Is there anything that Amazon doesn't have... I couldn't find all types though (angled / straight etc.), it would be easier if they were available at a specialist supplier, where you can order all part numbers.