Wiring thermostat to Vokera 25c boiler

[ianmcd]

COM and NO are marked on the terminals of your Nest E

 

[Emilia]

Ah I understand. So shall I just cut off the black plastic bit leaving bare wires and connect black and red to thermostat.
What should I do with blue and brown? Terminate them?

 

[Deleted member 267285]

Ok thank you. What is PCB and where is it exactly? sorry! I really don’t know any of this so completely relay on your expertise .

Pcb = printed circuit board and is where CN5 is located (the red board).

 

[vulcancontinental]

Just unplug the lead. Clock will be dead. nest to CN5.

 

[vulcancontinental]

Emelia, can you repost here please?

 

[Emilia]

Thank you all for your help the other day especially to Vulcancontinental . I’ve managed to connect my new nest thermostat to Vokera boiler but is now coming up with an error H153 couldn’t detect OpenTherm connection.
Any idea what this is for and what I should do?
I have Vokera 25c Easi-Heat Plus.
I eventually changed it to on/off and boiler seems to be working fine. Haven’t tried automatic on/off yet.
Many thanks in advance
Emilia

Read more: https://www.diynot.com/diy/members/vulcancontinental.144413/#ixzz793dSzbYh

 

[vulcancontinental]

Thank you all for your help the other day especially to Vulcancontinental . I’ve managed to connect my new nest thermostat to Vokera boiler but is now coming up with an error H153 couldn’t detect OpenTherm connection.
Any idea what this is for and what I should do?
I have Vokera 25c Easi-Heat Plus.
I eventually changed it to on/off and boiler seems to be working fine. Haven’t tried automatic on/off yet.
Many thanks in advance
Emilia

Emelia, I'm not sure everyone can see this but the link in your response is to my correspondence, could you delete the link please?

Yes, if you connected Nest at the OT terminals in the Heatlink they need to be taken to other terminals on the PCB, not CN5.

OpenTherm is good and I believe worth it but you will need what we call a controls interface that clips onto the PCB (https://www.mrcentralheating.co.uk/...MJRuemvyA09fRIFWkj3aXxPCypYzik1kaAkKMEALw_wcB part around £20)

The two wire from the Heatlink OT terminals go into the two left hand terminals of the four when the interface is connected to the board.

Look on YouTube

around 1 minute in you will see where the interface is fitted and which terminals to use.

If you use OT you can only set your domestic hot water temperature on the Nest, the selectors on the boiler are disabled as soon as OT is detected. I think it's in the equipment section of Nest options.

The EU recon OT is worth around 3% uplift in operating efficiency.

Last thing, get the boiler serviced to the manufacturers instructions please. Read them yourself and watch the guy do it. It will cost you more but I see so many skimped and from three years down the line to 7 years the exchanger gets blocked and suffers an early demise.[/QUOTE]

 

[Deleted member 267285]

Yes @vulcancontinental it’s a link to your profile page. Tbf though I could view it anyway, there is a way of limiting who views your profile, I think it’s in the settings somewhere.

 

[Emilia]

Apologies Vulcanocontinental, I wasn’t sure whether you’d be able to see my post here so posted on your profile. Have deleted it now.
Thank you for additional info re: OpenTherm. I’ll have a look and hopefully will be able to sort it out. Many thanks once again
Emilia

 

[Deleted member 267285]

Apologies Vulcanocontinental, I wasn’t sure whether you’d be able to see my post here so posted on your profile. Have deleted it now.

He should have seen it as he’d commented on the thread, but if you want you can use the @ and this will notify him as well, eg @Emilia