which smart thermostat

[gaz_moose]

I bought the drayton wiser one as suggested. The magic pixies might be responsible for installing it as its illegal for a non gas safe engineer to remove the cover or something like that.

[SimonD]

8 hours ago, -rick- said:

I'm not 100% sure I can fully use opentherm in my setup. I know it's supported with combis but with a S-plan system boiler I need to verify things. Unfortunatetly my installer really ballsed up the wiring and I'm not even running properly as S-Plan right now (there is one signal line to the boiler, not two) and thats before adding opentherm cabling. Royal Mail literally just rang my door and walked away before I could get to it with my delivery of stuff needed to change the wiring over. So guess I now get that delivery on Monday and will be able to report back how things go

 

With eph controls you can run priority hot water using opentherm on an s-plan system. You can also get an additional receiver to install right next to boiler for necessary opentherm communication so no new cabling required.

 

Use the cp4i together with cp4-hw-ot for this. 

 

No subscription fees for the app.

 

I wouldn't touch tado controls ever again after my experiences installing them for a few customers, even the ones I ordered from Europe with opentherm.

 

Hth

[-rick-]

On 22/11/2025 at 17:45, gaz_moose said:

I bought the drayton wiser one as suggested. The magic pixies might be responsible for installing it as its illegal for a non gas safe engineer to remove the cover or something like that.

 

Amazon now selling various packages even cheaper for Black Friday. Whether it's worth the hassle of returning what you ordered is up to you.

 

Magic Pixies have paid me a visit and now everything is up and running and working as expected. Looks like the 2nd Gen Wiser hub has better OpenTherm support. It's a shame in the sense that they don't appear to be backporting changes to the 1st Gen hub. Doesn't really matter to me, though the 2nd gen diagnostic info in the app would be quite useful. I wasn't planning on installing Home Assistant for this but might end up doing so just as I get used to the controls so I have a better idea what's happening.

 

So far the Wiser is running the boiler at the max setpoint temp (control on my boiler) until the room temp is very close to setpoint and then it winds the boiler down. Seen it drop the water temp to 42 so far though overall it spent more time at higher temps than I expected. I've read that it takes a couple of weeks for the system to learn your property and until then its control will be a bit bumpy. We will see. Don't think I'm seeing much cycling though without that diagnostic info and not wanting to stand in front of the boiler for ages it's a bit of a guess based on the noises I'm hearing. Not turned on eco mode (weather compensation based on internet weather) yet. That's the next step after a bit more experimentation without it.

Edited 8 hours ago by -rick-

[marshian]

On 22/11/2025 at 17:45, gaz_moose said:

I bought the drayton wiser one as suggested. The magic pixies might be responsible for installing it as its illegal for a non gas safe engineer to remove the cover or something like that.

Is your old controller base unit mounted on a universal backplate - sometimes called industry std backplate?

 

If it is a wiser hub should be easy to install no "gas safe" engineer required

 

I replaced my original controller below (library image as the original item got trashed by a toaster - don't ask some people are just stupid)

 

 

With a Danfoss 24/7 digital programmer that had a universal back plate - so I had the headache of working out what the wires did what on the original.

 

No smoke escaped from the wires so once done further swaps of the controller have been isolate power - remove old - replace with new and power up.

 

 

[marshian]

3 hours ago, -rick- said:

 

Amazon now selling various packages even cheaper for Black Friday. Whether it's worth the hassle of returning what you ordered is up to you.

 

Magic Pixies have paid me a visit and now everything is up and running and working as expected. Looks like the 2nd Gen Wiser hub has better OpenTherm support. It's a shame in the sense that they don't appear to be backporting changes to the 1st Gen hub. Doesn't really matter to me, though the 2nd gen diagnostic info in the app would be quite useful. I wasn't planning on installing Home Assistant for this but might end up doing so just as I get used to the controls so I have a better idea what's happening.

 

So far the Wiser is running the boiler at the max setpoint temp (control on my boiler) until the room temp is very close to setpoint and then it winds the boiler down. Seen it drop the water temp to 42 so far though overall it spent more time at higher temps than I expected. I've read that it takes a couple of weeks for the system to learn your property and until then its control will be a bit bumpy. We will see. Don't think I'm seeing much cycling though without that diagnostic info and not wanting to stand in front of the boiler for ages it's a bit of a guess based on the noises I'm hearing. Not turned on eco mode (weather compensation based on internet weather) yet. That's the next step after a bit more experimentation without it.

 

Having had Wiser for a few years now and gone down the route of smart TRV's and micro control of rooms my advice is keep it really simple if you are running a scheduled heating process (if 24/7 ignore me)

 

1. Set up base programme for Heating and Hot Water like you would an older digital programmer 

2. Device lock the Room Thermostat (so it can't be boosted accidentally - this is a fun game for all the family) and control in the app

3. Make sure the away facility does not apply to HW 

4. Steer clear of ECO and Comfort Modes until you are very comfortable with the system

5. If you notice the boiler being turned off mid cycle - change the boiler type to Oil. 

[-rick-]

10 minutes ago, marshian said:

Is your old controller base unit mounted on a universal backplate - sometimes called industry std backplate?

 

No opentherm connections there. A system boiler may also not be wired for separate CH and DHW signals which limits you to a single water temperature or in the case of the 1st gen wiser and similar prevents Opentherm use if you also want hot water. A competent installer can solve those problems.

[MrPotts]

The “industry standard” backplate will only fit the gen1 Wiser hubr, the gen2 hubr uses a slightly different backplate.

[marshian]

Just now, -rick- said:

 

No opentherm connections there. A system boiler may also not be wired for separate CH and DHW signals which limits you to a single water temperature or in the case of the 1st gen wiser and similar prevents Opentherm use if you also want hot water. A competent installer can solve those problems.

 

Sorry I was directing the question to @gaz_moose

 

My wiser unit isn't connected to the boiler at all - I'm heating 24/7 😉 Boiler is set up with DHWP and WC already

 

Wiser schedule for HW switches the boiler to recharge the cyl via a HW Demand box so there is actually no need to connect Wiser to the boiler.

 

I will eventually connect it again just to use the away function but right now I just use the Viessmann app to do that...

[marshian]

Just now, MrPotts said:

The “industry standard” backplate will only fit the gen1 Wiser hubr, the gen2 hubr uses a slightly different backplate.

 

Was not aware of that - thanks for the heads up

[-rick-]

23 minutes ago, marshian said:

Having had Wiser for a few years now and gone down the route of smart TRV's and micro control of rooms my advice is keep it really simple if you are running a scheduled heating process (if 24/7 ignore me)

 

Still working out which is best. Until the Wiser I've been running on manual boost as required, now exploring other options. One of my rooms has pretty much all its two external walls as not thermally broken aluminium double glazed floor to ceiling sliding doors and is hugely lossy. I don't really use the room so until now I've not be actively controlling the temperature there (just leaving some radiators relatively low and the room gets whatever heat comes from them when the heating is on for the other rooms). This arrangement has its downsides and I'm hoping that the efficiency gain of being able to run the boiler at a lower temp offsets the additional gas that I expect to need to regulate that rooms temperature (early signs not inspiring confidence).

 

Edit: I opened your big boiler journey thread earlier, not (re-)read it all yet but plan to. Thanks!

 

23 minutes ago, marshian said:

4. Steer clear of ECO and Comfort Modes until you are very comfortable with the system

 

Yep

 

23 minutes ago, marshian said:

5. If you notice the boiler being turned off mid cycle - change the boiler type to Oil. 

 

Came across that one in the wiser forums. Opinions are mixed as to whether it's a benefit on a good modulating boiler. (Mine goes from 30kw to 6kw)

Edited 4 hours ago by -rick-

[JohnMo]

20 minutes ago, -rick- said:

 

No opentherm connections there. A system boiler may also not be wired for separate CH and DHW signals which limits you to a single water temperature or in the case of the 1st gen wiser and similar prevents Opentherm use if you also want hot water. A competent installer can solve those problems.

For others reading this. If your system boiler has opentherm. The EPH unit referenced to by @SimonD (up thread) will make your system boiler supply different flow temps via opentherm, so your system becomes priority domestic hot water when using 2x 2 port valves.

[-rick-]

1 minute ago, JohnMo said:

For others reading this. If your system boiler has opentherm. The EPH unit referenced to by @SimonD (up thread) will make your system boiler supply different flow temps via opentherm, so your system becomes priority domestic hot water when using 2x 2 port valves.

 

Yep. Wiser 2nd gen will do that too along with some others, though had I seen @SimonD's recommendation before I bought I may well have gone with EPH.

 

Having said that, having the separate connections may be of use even if your boiler doesn't have opentherm (or a broken version of it). My relatively basic boiler will run the hot water at a hotter temp if triggered by a separate input to the normal heating circuit. It was my fallback position if I had a problem with opentherm.

[marshian]

22 minutes ago, -rick- said:

33 minutes ago, marshian said:

Having had Wiser for a few years now and gone down the route of smart TRV's and micro control of rooms my advice is keep it really simple if you are running a scheduled heating process (if 24/7 ignore me)

 

Still working out which is best. Until the Wiser I've been running on manual boost as required, now exploring other options. One of my rooms has pretty much all its two external walls as not thermally broken aluminium double glazed floor to ceiling sliding doors and is hugely lossy. I don't really use the room so until now I've not be actively controlling the temperature there (just leaving some radiators relatively low and the room gets whatever heat comes from them when the heating is on for the other rooms). This arrangement has its downsides and I'm hoping that the efficiency gain of being able to run the boiler at a lower temp offsets the additional gas that I expect to need to regulate that rooms temperature (early signs not inspiring confidence).

 

Edit: I opened your big boiler journey thread earlier, not (re-)read it all yet but plan to. Thanks!

 

Sounds like you have a similar issue to one of my rooms 

 

Good luck reading the Viessman thread it's taken me a while to get to grips with it!!! It's still got some niggles!!!

 

22 minutes ago, -rick- said:

 

 

 

33 minutes ago, marshian said:

4. Steer clear of ECO and Comfort Modes until you are very comfortable with the system

 

Yep

 

I think they can be good but they also a layer of WTF which can be confusing

 

22 minutes ago, -rick- said:

 

33 minutes ago, marshian said:

5. If you notice the boiler being turned off mid cycle - change the boiler type to Oil. 

 

Came across that one in the wiser forums. Opinions are mixed as to whether it's a benefit on a good modulating boiler. (Mine goes from 30kw to 6kw)

Edited 7 minutes ago by -rick-

 

It's not really anything to do with the boiler ability - more an algorithm in the Wiser control program - it's especially bad with multiple "smart" TRV's and 24/7 heating but it can just as easily do the same with a single room stat 

 

Main Room with thermostat (or multiple rooms with "Smart" TRV's) get close to target temp and Wiser switches off the boiler - it's one of the reasons my Wiser hub doesn't have a connection to the boiler now - I'm running 24/7 with WC and TRV's are set to temp limiters (just above target temp - so it was interpreting that as potential house over heat and shutting down the boiler 

 

Switching it to "oil" reduced the frequency of that intervention - it's just something to bear in mind when setting target temps or placement of the thermostat.

 

I'm still a fan of the Wiser system - I've just dialed out the clever - I don't need or want ECO I'm running flow temps below 35 deg  - I don't need Comfort because I'm not scheduled heating slots and WC is doing all the hard work.

 

The App interface is brilliantly simple just don't try and make it complicated