Worcester Bosch Greenstar 30 CDi Classic + EasyControl - how to replace with Wireless Strtr Kit?

Rich_b

Hi all, I've been chatting to Tado support, who confirmed that my heating system is compatible with the Tado wireless starter kit, but they advised I'd need a heating engineer to install it.

I had an engineer visit yesterday, who took one look at my setup and advised that it was non-standard and they didn't have the experience to tackle the job.

So, ideally looking for help/advice on whether it really is compatible, and if it is, some general guidance on how to go about connecting it.

My setup -

Worcester Bosch Greenstar 30 CDi Classic System Erp system boiler with a hot water tank, the hot water is delivered under pressure.

I was sold it as a 'system' boiler, but looking at the install guide, I suspect it's a combi boiler with an optional internal diverter valve fitted for the hot water cylinder. I cannot see any other valves (3-way etc) anywhere.

My current programmer/thermostat is a Bosch EasyControl, that is wired directly to the boiler, where I can programme schedules for both heating and hot water. This is installed to the hallway wall, but my plan with the wireless starter kit is to move the thermostat function into the living room (away from the cold hall).

Has anyone connected to or replaced anything similar? Is it a straight-forward replacement job (assuming you get the re-wiring correct), or is it more complicated than that? Can one of the professional installer guides be followed for this setup?

The heating engineer didn't seem to expect that my existing Bosch EasyControl appeared to be using low voltage cabling, is that an issue when attempting to replace it with the Tado?

Thanks in advance,

Rich

GrilledCheese2

Your Bosch controller is using digital communication bus called EMS. It’s a two wire system for controlling both HW and CH. Tado supports older versions of EMS but it looks like they don’t support the newer boilers (Worcester keep changing the protocol). Have Tado confirmed that they definitely don’t support your model/age of boiler using EMS? Your boiler is a system boiler - all the ancillary components are internal.

Rich_b

Hi GC, thanks for responding.

I've not managed to get a straight answer out of Tado support except for them initially advising that my boiler/controller is supported.

I've message them again, I might need to ring them up and pretend to be a heating engineer.

Cheers,

GrilledCheese2

If your boiler is not supported with EMS then the traditional relay method will have to be used. This will require a 5-core cable between the boiler and the receiver. If your current cable is only two core it may require you to mount the receiver next to the boiler. Definitely not a DIY job, but a heating engineer should know what needs to be done.

Rich_b

I heard back from Tado support -

==================================

Hello Richard,

tado° Wireless Receiver is designed to work with UK S-plan and Y-plan heating. With Relay controls.

It does not support digital installations such as EMS protocol/bus.

If you want to proceed with the Wireless Receiver installation, it needs to be wired to control the Heating and Hot Water zone valves. Instructions for that are in this manual:

Wireless Smart Thermostat [Incl. Programmer with Hot Water Control] Manual

To control the boiler digitally with EMS protocol/bus, you would need the older model of the tado° programmer, the Extension Kit, or a tado° Smart Thermostat, which would then be installed as wired.

Smart Thermostat can be purchased from our shop.

We do not sell Extension Kits anymore, but they can still be bought from other retailers.

Instructions for that are in these manuals:

Extension Kit Manual - Low Voltage Digital Installations

Wired Smart Thermostat Manual

Forward the link for professional manuals to your installer, and have them call us if they have more questions.

===================================

I have to admit, I'm confused by the references to the extension kit and wireless receiver, I've bought the wireless starter kit from Screwfix (https://www.screwfix.com/p/tado-v3-heating-hot-water-wireless-smart-thermostat-starter-kit/141kt) , and this includes the wireless receiver, I think?

Anyway, reading GrilledCheese2's comment on the feedback from support, it looks like I can use the wireless starter kit, inc the wireless receiver, but will need to replace the wiring. I guess this will incur additional electrical work and costs.

My boiler installers have put me in touch with the heating engineer/electrician they use. I'll provide him with pics of the boilers current wiring connections and try and gauge how confident he is.

Thanks,

Richard

GrilledCheese2

@Rich_b the starter kit you have purchased consists of a wireless receiver and a wireless temperature sensor. As stated by Tado this UK variant does not support EMS bus. The EU variant does support EMS bus, but is not for sale in the UK.

I think you have another option that is worth discussing with Tado. Return the wireless starter kit and purchase the wired starter kit. The wired thermostat supports EMS bus and won't need additional wiring if you mount it in the hall in the same location as your current thermostat. Ask Tado if you purchase a separate wireless temperature sensor (not a kit) and mount it in the living room can you pair it with the thermostat in the hall? Meaning the living room device is the only device to read the temperature and the hall device is simply controlling the boiler for both CH and HW.

ajmross

@GrilledCheese2 @Rich_b very informative thread, I'm a newbie and think the info here is helping me work out my plan for installation, but I would welcome your feedback.

In the UK, I'm renovating a house, a whole new plumbing and electric system - everything is ripped out. The plumber plans to install a Worcester Greenstar 24i system boiler, Wolsely Prolite indirect unvented cylinder 210ltr, Heatmiser UH4 - 4 Zone 230v Wiring Centre (with actuators on each port of the manifold) with three heating zones for downstairs UFH. We'll also have 3 upstairs rads and 1 in the hallway where there is no UFH.

To make this work with tado, I've bought the tado wireless starter kit, 4 tado TRV and 3 wired tado stats.

The plumber has no experience installing tado.

Tado support has simply said "your boiler is compatible" and hardly been any more helpful than that, as looking at the instructions it seems it may be quite complicated to make it happen. I'd like some confidence that this is going to work as intended to control hot water and heating across all zones and rooms.

Will this work? Do I need something else from tado? Or would I be better off asking the plumber to choose a different boiler brand? I've been trying to find some kind of info that says "this boiler works best with tado in this set-up", but can't seem to find it.

GrilledCheese2

@ajmross the equipment you have purchased should work fine with the WB boiler. The UH4 box uses traditional 'switched live' (not a digital interface), so there won't be any compatibility issues. The Wireless Receiver will need to be connected to one of the CH zones and the HW zone in the UH4.

If you are fitting 4 TRVs to 4 radiators there will need to by a bypass valve for the radiator circuit - there has to be a path for the water to flow when all 4 TRVs close. Also, when every radiator has a TRV then group the radiator wall thermostat with one of the TRVs. This wall thermostat will then be the temperature sensor for the one TRV. Otherwise you will have 5 rooms/schedules for 4 radiators.