Switching from Danfoss to Drayton WT734

[aidiy]

Hi,

I’m a newbie here and apologies in advance if I’m repeating this topic but I couldn’t find answers on other posts hence posting this.

So I’ve Danfoss system with Ideal combi boiler that came with this new built home I purchased few years back. Our boiler is on ground floor in kitchen, a large Danfoss junction box and 2 Danfoss valves on first floor in a cupboard, one TP40704 controller on ground floor and another one on first floor.
All was going well and I never bothered to look at replacing this with any smart heating things like Hive etc but recently our ground floor thermostat started playing up and it won’t turn on heating, I tried resetting, replacing batteries etc but nothing worked so I took it off to take a look at wiring and now accidentally broke the pin connectors that connects thermo stat to back plate and hence need to replace it to keep our heating going thru winter.
And because getting the same Danfoss thermostat to replace works out as expensive as putting a smart thermostat, I bought this Drayton system that as advertised should be a simple one to one replacement. However when I opened up the Danfoss junction box it has much more wires than shown in Drayton manual. Only wires I can clearly identify are the ones that are going to 2 valves(one up and one down) and 2 each for up and downstairs thermostat.
Can someone please help to decode this wiring and how do I wire the new Drayton control box instead?

I have attached some pictures below for reference -
First one is wiring in the Danfoss junction box, 2nd is 2 valves, 3rd is current thermostat, and 4th is Drayton backplate.

 

[Mister Banks]

The first picture is the wiring centre which you shouldnt need to touch. The Drayton goes where the existing Danfoss programmer is located.

 

[aidiy]

Thanks Mister Banks! That’s what I thought but I only have 2 thermostats that are programmed individually and they are battery powered with 2 wires coming from the junction box that’s connect them to boiler. I assume 2 thermostat that came with the Drayton kit will replace them but not sure where the Drayton control box will go in that case ?

 

[RandomGrinch]

The first picture is the wiring centre which you shouldnt need to touch. The Drayton goes where the existing Danfoss programmer is located.

I believe the OP may be calling the two battery operated thermostats the 'controllers'.


The three channel Wiser hub would mount by the wiring centre.

You could take a L from terminal 1 of the wiring centre
N from terminal 3
And an earth from terminal 6

And then...
Remove the black wires from terminals 9 and 10 of the wiring centre.
Terminals 1 and 3 of the Wiser hub can then connect to 9 and 10.

The two corresponding brown wires (to the black ones), in terminal 1 of the wiring centre, can also be removed, to make the wiring to the original stats safe.

 

[aidiy]

Many thanks. This makes sense to me now. I will give it a go tomorrow and let you know.

 

[RandomGrinch]

Many thanks. This makes sense to me now. I will give it a go tomorrow and let you know.

If there's anything that you are unsure of from my description, let us know.

Good luck!

 

[aidiy]

Hi @RandomGrinch. it’s been sometime since you responded to me on this, but somehow because of other priorities I gave up on this but now looking at it again to see if I can fit it as per your directions as my thermostats are giving troubles.
Before I attempt it I do have one confusion I hope you can guide me on. how do I identify which brown wires need to be removed from the wiring centre terminal 1 to isolate the original thermostat?
Thanks

 

[CountryFan]

@RandomGrinch hasn’t been on for a while and I hope he’s ok. 9 and 10 are your room thermostats.

 

[aidiy]

Many thanks @CountryFan. Really appreciate it.
I hope @RandomGrinch is ok.

 

[CountryFan]

Many thanks @CountryFan. Really appreciate it.

You’re welcome. Although, having re-looked I think number 1 might be the common to your room thermostat, which also appears to be permanent live, so if it’s comes from a fuse don’t connection unit, then I’d say you can probably just pick 2 and leave one in.

 

[aidiy]

Ok so disconnect 2 of 3 wires at terminal 1?

 

[CountryFan]

Ok so disconnect 2 of 3 wires at terminal 1?

I would say so yes, but isolate them safely if you need to refit them.

 

[aidiy]

All done last weekend and has been running without any issues. Thanks @RandomGrinch and @CountryFan.

This YouTube video also helped to understand the whole wiring

 

[ericmark]

If we look at the universal backplate with the likes of Hive and Drayton Wiser there are three options, with a combi-boiler the two channel is not really required, as the second channel is for domestic hot water so either one or three channel. In the main when moving to Wiser there is no need for two motorised valves, as the TRV heads are changed to motorised types, so the TRV is a motorised valve. The easy way is just to connect both valves together so they both open when the boiler is required, they could be removed, as not needed, but that's a lot of work.

So I have in my own house a single channel Wiser hub, and 10 electronic TRV heads, so I can select when each room is heated, but only one of the TRV heads is linked to the boiler, I use two wall thermostats, and I have found that to be enough, basic the TRV stops an unused room from being heated.

But this means sitting back and deciding what you want, which is likely different to what I want. And also what you have bought, have you got a 1, 2, or 3 channel hub? All can be used, but the way they are wired changes. I could have used a three channel in this house, and used it to split main house and flat, but the flat rarely used in winter, so I use an old mechanical thermostat for my flat.

So what have you got, and what are your aims, both now and in the future. For example, I have given up with geo-fencing, and my boiler will not run OpenTherm, so I am not worried about those features.

 

[aidiy]

I had 2 zone wired Danfoss thermostats that I simply replaced with wiser hub using channel 1 and 3. Channel 2 is not used as I’ve combi boiler and water is on demand.