Smart heating options for 15 year old Worcester Combi

DougMLancs

We just bought a 3 bed 1950’s semi  with a 15 year old Worcester Greenstar 25CDI Combi boiler in the kitchen with a Worcester MT10RF controller (wireless but currently fixed in the hall). All rads apart from the hall and landing are fitted with Danfoss manual TRV’s. 

We would like to look into smart heating to give us better control over the scheduling and incorporating features like weather compensation. Smart trv’s are being considered but equally if I can set up the manual ones to do roughly the same job without the long payback then I’ll skip them.

I’m considering the likes of Tado and Drayton Wiser but since they can’t speak EMS then will I lose any modulation ability? Does this also mean 3rd party features like weather compensation won’t work with a Worcester? 

I spoke to Worcester about the options for my boiler and they said I can get an EasyControl adapter that makes their EasyControl system work with my boiler but it’s not clear if that just simplifies what signals can be exchanged and ends up with no advantage over an off-the-shelf 3rd party system. Can anyone with more knowledge of heating controls than me help clarify things please?

BUFF

I am in a similar situation except with a 14 year old Highflow 440CDi & whilst I have a WB digital programmer I have a Siemens RDH10RF room stat (this is already Class 4 as it has TPI). I have manually turned down the flow temp.

Afaik whilst your setup is mechanical it can already set different temps for different times?

My understanding is that as Tado, Wiser etc. can't communicate at EMS level you will still have modulation but not the more granular "advanced modulation" which afaik can gain you up to~3%. I believe that smart features like learning how your house performs thermally &  tieing in with using weather information for incorporating that into "optimal start" (or whatever you want to call it) should work. As should features like geofencing.

the 25CDi (nor mine) doesn't appear on the latest compatibility list for EasyControl that I can find. However, hopefully tech support will have the latest information.
My understanding was that the EasyContol adapter was for using the control on another manufacturer's boiler with Opentherm or an on/off interface & as our boilers don't have Opentherm ...
Also, the wireless version of EasyControl uses an RF key which plugs into a dedicated socket in current WB boilers - I bet that yours & mine don't have that socket.
& afaik the EasyControl needs a permanent power supply cable connection.

My current thinking is to stick with what I have until this boiler needs changed & update with a better controls solution at that time (if it is another WB that also gets you a warranty on the controls for as long as the boiler - potentially up to 12 years).
A 3% improvement for my gas consumption would be ~£24 p.a. saving at EPG rates so even if I could gain that 3% on this boiler it would take 4+ years to break even on the investment & that is doing it myself rather than using an installer.

DougMLancs

Thanks BUFF- that’s really helpful. maybe I’ll stick it out with you then.

FreeBear

There is (was) an adaptor available to convert from OpenTherm to EMS that would allow you to use the Wiser system to communicate with the Worcester boilers. Search for "Nefit OpenTherm Adaptor", although I don't think it is available in the UK.

If you don't want to order a Nefit adaptor from the continent, the only alternative that springs to mind is a home brew system. Perhaps ems-esp to handle the boiler interface and Home Assistant to do the "smarts". That said, I wouldn't be at all surprised if there wasn't a project out there that used an ESP32 board to handle OpenTherm<->EMS conversion. Really depends on how tech savvy you are and your desire to get your hands dirty.

DougMLancs

Thanks FB, I’ll look into it. I’m reasonably savvy and always like a project. Convincing the OH about including parts not off-the-shelf might need some work mind 

FreeBear

DougMLancs said: I’m reasonably savvy and always like a project. Convincing the OH about including parts not off-the-shelf might need some work mind 

All the parts you need are "off the shelf". Maybe not a shelf that your average OH would visit, but off a shelf regardless. Parts such as a Raspberry Pi (I'd prefer a nanoPi Neo or Neo Air) are readily available from any number of sources. An interface board for the EMS bus is the tricky part. A ready assembled one can be purchased here - https://bbqkees-electronics.nl/product/ems-interface-board-v3/ - But once shipping is included, it is expensive. However, it is a trivial circuit, so easy to breadboard if you have a soldering iron.

Two things to note....

SD cards do not last long if you are logging data - I was killing one every two to three months with my Pi.

One you start logging temperature in just one room along with boiler run time, you'll start wanting to record even more data. Temperature & humidity in every room (plus outdoors), energy consumption, time lights are on, etc, etc. It is a rabbit hole you may not emerge from.

DougMLancs

Haha that sounds like my kind of rabbit hole! Once the solar is fitted too then people will ask “any hobbies?” “Yes, monitoring my house” 

rob7475

I have a 12 year old WB Greenstar combi boiler and have been using Tado for around 7/8 years. It's great and does exactly what I need. Geofencing works great, weather adaptaion works fine.

It does kind of modulate the water temp in the radiators. There's 3 heat levels on Tado depending on the heat of your house and the outdoor temp. Sometimes, if the heat just needs 'topping up', the radiators get luke warm rather than red hot. To achieve this, Tado fires the boiler intermittantly rather than modulating the flow temp.