DanFoss TP-One M Confusion

M1KEY

Hi there,

Hope you may be able to help please.

I live in a new build property, with 2 heating zones. Both are controlled independently of one another using the DanFoss TP-One M thermostats. Combi boiler, no HW tank, Ideal Logic ESP 1 boiler.

I had initially planned to replace the thermo in the hallway with a Wired Thermostat X, and the one in the bedroom with a Wireless Starter Kit X. This was just because the hallway looks fine with the thermostat on the wall, but in the bedroom, I'd rather it was on the nightstand. The bedrooms are heated in one zone, and the hallway and lounge in another zone.

I contacted Tado initially to request support to confirm compatibility. They confirmed it would be fine, BUT, I'd be better off having two wireless kits rather than a wired and wireless, because the app supposedly will only show me how to setup the wireless kit, not the wired.

Their reasoning was that TP-One Ms are 'programmers' and not thermostats - I can't find anywhere what the difference is, as my DanFoss both sense temperature and switch the heating on/off based off of the target temperature..

I understand that the DanFoss TP-One B however (not the M that I have) has instructions to replace with a wired thermostat X - and from what I have found - the only difference between the B and M model is one is live powered and one is battery powered (B for battery).

I have seen elsewhere that there are suggestions to instead choose 'TP-One B' in the app when setting up to receive the instructions, but I hadn't seen any success stories. I understand if you choose 'TP-One M' when trying to set up the wired thermostat, it says you can't because it's a programmer not a thermostat..

The wiring of my TP-One Ms looks very straight forward (attached) - and I can't quite understand the difference between the Wireless Kit X and the Wired Thermostat in terms of why one would work 'out of the box' and why the other wouldn't with the instructions?

Any thoughts greatly appreciated! Thank you

policywonk

Going through this slowly.

1. Your boiler's installation guide states that it operates in both dumb-on-off mode, as well as in full digital control. Logic-Code-Combi-Esp1-Installation-And-Servicing-222364-1_inst.pdf. It is a modern boiler which, studying its performance curves, it is capable of saving money, usually at least 8%pa, more likely 9-11% of annual running costs if operated in digital mode.
2. Your Danfoss TPONE-M devices are definitely thermostats with built in time programme control-but wired to operate the boiler in dumb on-off switched mode.

This needs thought. You have two options right now.

1. The swiftest and simplest change is to swap out the Danfoss controls with two WIRED Tado thermostats directly replacing the Danfoss devices. These will operate the zone valves and fire the boiler in dumb mode as before. Also purchase a Tado wireless sensor and configure the wireless sensor to drive the preferred wired thermostat (so that the wired thermostat switches the valves and the boiler when the wireless sensor asks for it). The App will then control the heating schedule.
2. The second , if you want to benefit from the full digital throttle controls that enable your boiler to operate in Opentherm digital mode, without a major rewiring of the wiring centre. would involve
   1. Putting the two wired thermostats in place as before
   2. Fitting the single wireless sensor as before.
   3. Adding a wireless receiver (aka extension kit) which is directly wired to the boiler, commanding it in Opentherm mode. The wiring centre would then be slightly modified to not allow either thermostat to wake up the boiler directly. Only the wireless receiver could do that.
   4. The two thermostats would then command the wireless receiver, whilst opening their zone valves when needed. The wireless receiver would then wake up the boiler when either of the thermostats call for heat.

Any questions?

M1KEY

Thank you! This has been so helpful!

So I actually went ahead and got the wired thermostat for one of the placements, and wireless for the other (working them in dumb mode at the moment), but definitely have ambition to move to OpenTherm in the future. (I had already gotten the wireless one before your reply)

My initial research had told me that due to having the motorised zone valves, OpenTherm was a no-go, but it seems that there might be a route!

I wonder how that would work in terms of App Setup? I figure that the Wireless Receiver would be the zone controller (wired to the boiler, speaking OpenTherm), and then the two wired thermostats would be 'reporting' into the Wireless Receiver. That being said, so that the wired thermostats can open the valves, I imagine they would also need to be classed as zone controllers, so that they could 'call for heat' (but are actually just connecting the relay so it opens the zone valve?). If I don't have them set as zone controllers, then I'm not sure if the relay would activate in it to make the motorised valve open?

Thanks again - your help is really appreciated.

policywonk

@M1KEY One thing, forgot to mention. Apologies, was handling a couple of emergency team, at the time and this slipped my mind.

The present UK version of the Tado Wireless Receiver (aka extension kit) doesnt talk Opentherm, it only works in dumb mode. However the Tado EU wireless receiver does talk Opentherm, and so does the previous UK version (the model with the letters BU in its serial number). If its not too late would you be able to either:

• make sure you've got the EU version (send the other one back),
• or go on Ebay and buy the older UK wireless receiver (its model number or serial number starts with the letters BU) - and it works fine with V3 series - and does talk Opentherm?

You'll need to contact support and get them to give you specific instructions on how to configure the individual thermostats, the wireless sensor and the wireless receiver, IN WRITING. When you've read the instructions, if lost, come back. We have a few people here who've gone through this and will probably want to help.

The logic they give you will likely go like this:

1. The two wired thermostats will likely be wired in relay mode, each directly assigned to a virtual room and will, when there is a call for heat,open their respective zone valve. One day in the future you might decide to add smart TRVs on your rads, and remove the two zone valves, to make the whole system more efficient, but not today. First job is to prove it can all work.
2. The wireless sensor should be added, assigned as the zone controller for the "room" which needs a portable sensor. When it wants heat, it then tells its respective wired thermostat at what temp to switch on and off.
3. The zone controller to rule them all is your wireless receiver. Both thermostats will wirelessly inform the wireless receiver that there is a call for heat and the wireless receiver will pass on the dynamic heat demand curves it receives from the thermostats (these are built over time), to the boiler - and the boiler receives this and kicks off:
   1. Watching its ouput pipe temperature sensor
   2. Watching its return pipe temp sensor
   3. Calculating the rate at which the two change and reconciling that with the curve given to it.
   4. The learning process takes months and as the weather changes, Tado's backend adjusts the curve to allow for weather differences.

Need any more?

M1KEY

Ah that's brilliant, thank you so much for all that depth. All makes sense. I am pleased to hear that it's something that the team at Tado might be able to help me to setup. I had thought OT was a complete no-go based off of my previous reading, so I am glad that it's doable.

Interesting that you mention that the TRVs would mean that the zone valves would need to go - I had considered perhaps popping some TRVs into the rooms (specifically the bathroom), and I understood that this would work as it would tell the respective zone controller it needed heat and would turn the boiler on, and also open the zone valve. Unless you mean that in this situation where we are discussing OpenTherm, that the TRVs would replace the zone valves in that instance?

RE the wireless version not including OpenTherm - My Tado X wireless receiver box specifically says 'including hot water control and OpenTherm', so I would certainly hope it does have OpenTherm?!

Thanks again :)

policywonk

My bad. Brain was elsewhere. Yes the x series does handle opentherm.
If you elect to remove the zone valves at a later time come back and we'll help.
Don't put smart trvs on rads where there is high humidity, it messes with the readings. Also don't fit the smart trvs until you've removed the zone valve for that zone, otherwise you'll face a contradiction sometimes when the rad asks for heat and the zone thermostat does not allow it in because it's temp reading isn't close to what the radiator in need is seeking.