Tado X with relay operation or V3+ with some poor connectivity to SRTs

Kissarmy

I've recently been posting about getting my Vaillant 937 working with a VR33 module so that I could control it via Opentherm rather than Vaillants proprietary ebus. I had just got that working and was awaiting my second delivery of Tado X parts when disaster struck. No hot water. The 937 is a complicated boiler with what Vaillant call a shift load water tank behind the combi boiler part that had its own sensors, pcb, expansion vessel and pump.
Before calling out Vaillants £399 fixed price repair service I rewired the V3+ system back to ebus control and removed the VR33 module.
My boiler is out of warranty but I know Vaillant class using a VR33 in the UK - even if installed by a qualified Vaillant tech - as invalidating the warranty. What I do not know is whether or not Vaillant will fix a UK boiler with a VR33 installed.
My wife has now pointed out the flaw in my plan. I was so concerned with making modulation work with Tado X that I did not think of the consequences. I work away from home a lot, months at a time, and my wife wanted to know what would happen if the boiler broke down while I'm working abroad because she wouldn't be able to remove the VR33 and rewire the system to run via relays.
So my conundrum is do I run the Tado X system via relays losing the benefits of modulation or do I return the whole stack of Tado X boxes as I'm within the 14 day distance selling rule and stick with the V3+ system which has modulation but suffers from dropouts on radiators SRTs because of the house having thick stone internal walls and the limitation of 1 Internet bridge.
Why oh why has Tado gone backwards losing compatibility with manufacturers proprietary digital standards like Vaillant ebus.

Emcee

Hello @Kissarmy

Would it be possible to return your set-up to relay before you leave? If your wife is worried about it, it might be easier to only have it on OpenTherm when you're home.

Kissarmy

@Emcee It is a workaround - though it is a faff. Will Tado servers be okay with my house making changes from opentherm to relay and back? How much efficiency will I lose going from modulation to relay control? I saw a post where you commented that the intention is for X to offer every feature that V3+ has and vice-versa - can I take it from that that there is the intention to offer ebus control on X in the future to match the V3+ feature? My boiler will need replacing in a couple of years and I don't believe there is anything opentherm compatible on the market that matches the Vaillant 940 (updated version of 937 that I have now). I was also told by a Vaillant service engineer that the new Plus 2 models are too clever for their own good and would fight a system like Tado trying to emulate modulation by relay control. The way things are going Vaillant needs to stick with digital control in order to properly control what the boiler is doing irrespective of what the manufacturer thinks is right.

Emcee

Hello @Kissarmy

Regarding the feature question, I was more referring to things like Early Start, more Smart Schedule options, Preheat Before Arrival. I wouldn't hold my breath for eBus (although, never say never).

I don't think you changing from Relay to OpenTherm will have any effect on our servers. However, I can imagine that the more times tado° is re-set, the likelihood of something potentially going wrong with the set-up also increases.