Drayton Wiser retrofit - Rads + Underfloor Heating - Which HubR Kit?

[Mark Haines]

Hi I've just moved to a new house and I’m looking to replace my current heating system controls with a Drayton Wiser smart system.

I have an Ideal Vogue Max System 32 boiler with water tank, a basic Drayton thermostat that controls hot water on a timer and a Salus thermostat. I also have a separate wet underfloor heating system with 3 x separate zones (currently without zone control) controlled by a single Salus thermostat.

For the underfloor heating I think I need:
1 of https://thesmartthermostatshop.co.uk/product/drayton-wiser-underfloor-heating-controller/ to replace the existing unit.
3 of https://thesmartthermostatshop.co.uk/product/drayton-wiser-smart-room-thermostat/ one for each zone

For the radiators and hot water I think I need:
1 of https://thesmartthermostatshop.co.uk/product/drayton-wiser-thermostat-kit-2

I can then slowly add smart TRVs later on if needed.

BUT what I’m not sure is whether I need the Thermostat Kit 2 or (because of the underfloor heating system) the Thermostat Kit 3? Does the underfloor heating system count as an extra zone for the Hub to control or is that purely if I was to have zoned radiators?

Bonus question: should I just replicate the wiring connectivity 'as is' or should I look at Opentherm wiring to the boiler - I believe it is compatible?

 

[ian1182]

I assume both the UFH and radiators (+ hot water) are heated by the boiler.

What is you current programmer setup. You mention three thermostats but no programmer. Normally the setup would be a thermostat attached to the HW tank + 1 or more room thermostat(s) connected to a programmer. You could for example have a roomstat for upstairs, roomstat for part of downstairs and another for the UFH area

The UFH does not necessarily add a channel to the Wiser Hub requirements. It depends on how many heating circuits you have. For example if you had one zone valve handling hot water and a second looking after the radiators & UFH combined that would be 2-channel model. But if the radiators and UFH are on separate circuits you may need a 3-channel model.

I think you should expand on the current setup.

As for opentherm, I believe that's a work in progress for Drayton/Schneider. My understanding it's only really works with 1-channel models.

 

[Mark Haines]

Thanks for piling in. Yes, let me flesh out what I have currently (and also correct some of my terms). Full disclosure; we've just moved in and the previous owners split up before the extension work was completed so there has been some perhaps questionable decisions made..

Boiler = Ideal Vogue Max System 32
- Joule tank
- Single boiler feeds all systems

Upstairs Rads + Hot Water
Programmer = Drayton LP241 - does hot water on a timer
Remote (wired?) Thermostat - Salus, located upstairs

Downstairs Underfloor Heating
Thermostat + Programmer = Salus wireless unit
Heatmiser UH4 controller
- 3 of 4 zones are used
- No individual controls.

One sensible thing they did do was relocate everything to the garage so it's really easy to access and work on. Photo below in case it's useful.

 

[ian1182]

If the replacement was just for the LP241 and associated thermostat that would be easy! Basically undo LP241 and replace by Wiser on same backplate plus some minor rewiring for the roomstat. And you are done

but it's more complicated unfortunately if you want the Wiser to look after HW + CH + UFH.

Next question...
Can the UFH independently "fire up" the boiler when the HW and upstairs heating is in "off" period. If so that implies you have 3 channels (HW, CH & UFH)

If the UFH can only be "on" when the LP241 CH is also "on" that implies 2 channels (HW + combined CH/UFH).

If you have 3 channels, some rewiring will be necessary as to state the obvious "the LP241 only handles 2 channels and hence something else does the 3rd channel".

I'd recommend, with the boiler power off, to remove the wiring centre cover and map the various connections. You are fortunate everything is in one place. Hopefully you can follow the cables. More than likely you will have an "S-PLAN PLUS" arrangement which looks after 3 channels.

A good place to look is google "flameport s-plan". There are some excellent explanations of the wiring at that site.

Based on what I can see in the picture you seem to have a pair of Salus receivers which presumably connect to a pair of wireless thermostats.

 

[dilalio]

3 zones = kit 3 (3 channel hubr)

 

[Mark Haines]

I'd recommend, with the boiler power off, to remove the wiring centre cover and map the various connections. You are fortunate everything is in one place. Hopefully you can follow the cables. More than likely you will have an "S-PLAN PLUS" arrangement which looks after 3 channels.

A good place to look is google "flameport s-plan". There are some excellent explanations of the wiring at that site.

Based on what I can see in the picture you seem to have a pair of Salus receivers which presumably connect to a pair of wireless thermostats.

Thanks, yes - the UFH can fire the boiler independently of the status of the LP241. I'll have a google on the wiring config you mentioned and have a look under the cover on the centre cover and map it out as you suggest.

 

[dilalio]

Thanks, yes - the UFH can fire the boiler independently of the status of the LP241. I'll have a google on the wiring config you mentioned and have a look under the cover on the centre cover and map it out as you suggest.

Do you have 3 motorised zone valves?
Is the UFH controlled by an MCV?

 

[Mark Haines]

Do you have 3 motorised zone valves?
Is the UFH controlled by an MCV?

Yes and yes. That's the Heatmiser UH4 in the photo, I'd replace that with the Wiser equivalent.

 

[Mark Haines]

Thanks, yes - the UFH can fire the boiler independently of the status of the LP241. I'll have a google on the wiring config you mentioned and have a look under the cover on the centre cover and map it out as you suggest.

I have 3 x zone port valves, so I think that answers my original question - I'll go for the Wiser Kit 3.

This page is also useful for explaining S-Plan setup (for anyone referring to this thread in the future): https://myboiler.com/s-plan/

 

[ian1182]

I have 3 x zone port valves, so I think that answers my original question - I'll go for the Wiser Kit 3.

This page is also useful for explaining S-Plan setup (for anyone referring to this thread in the future): https://myboiler.com/s-plan/

They key thing to understand is the wiring as it affects the boiler operation. The wiring centre is the white rectangular box with 8 cables going into it. More than likely the cable running to the LP241 is 5-core (Line, neutral, earth, HW & CH), the 3-channel Wiser should have a 6-core cable (L, N, E, HW, CH & UFH). You should avoid using any green/yellow core for anything bar earth. Whilst neither the LP241 or Wiser require an earth it's good practice to connect one and also it's not recommended to use the "earth" core for anything else.

Whilst the wiring centre looks complicated initially, once you trace the links to valves, thermostats, pump, boiler, programmer, etc it becomes much clearer how it all hangs together. Hence view the JW videos should help.

 

[Mark Haines]

Ok, so have made progress; I bought Wiser Kit 3, Wiser UFH Controller, Wireless Thermostats for each of the 3 x UFH, a few Wiser Radiator TRVs to play with. I successfully replaced the old Drayton programmer and Selus remote Thermostat and now Hot Water & Central Heating radiators are working perfectly with the new Wiser system.

I worked out the wiring at the wiring centre and it is a perfect match to the S-Plan he runs through in the Flameport video as @ian1182 suggested.

As it turns out, I didn't need the 3 zone HubR, the 2 zone would have been fine as the UFH can act as an independent device that the HubR can control wirelessly as it has a 'boiler contact relay' built in. As a last resort i could rewire it to work as S-Plan+ through the wiring panel and control it via CH2 on the HubR but I'd rather not if I can avoid it.

I've got power to the UFH, power and control to the pump and have the 3 x UFH zones correct correctly. Where I'm stuck is how to correctly connect the 2port valve that controls the UFH part of the system. I believe I need permanent live to grey, neutral to blue, earth to green / yellow but am unsure what to do with the brown and orange - i'm sure the solution is really simple but i'm suffering from brain freeze! Diagram below.

 

[ian1182]

Do you have a separate pump for the UFH or is it shared with the HW & CH? If it's shared, that implies the boiler controls the pump. Excluding the smart side of the Wiser, in essence all its doing is applying 240V to the brown wire into the 2-port valve. The valve orange connection should not need to be changed. If however you have a discrete pump for the UFH then it probably needs to receive power the Wiser UFH controller.

With that said, I suspect the first thing would be to understand how the UFH switching worked prior to installing the WiserHub. Once you know the electrical connections hopefully replicating that in the new arrangement should become clearer.

Also whilst you may only need to use HW and CH1 on the Wiser hub, at least you got 2 roomstats as part of the package. The cost delta between the Kit2 and Kit3 is mostly the roomstat.