Nest Install - Communal Heating HIU Evinox MTP 40-10E Modusat (E-ON)

[MattG07]

Hello members,

Does anybody know how to wire a heat link to an Evinox HIU?

I know I need to replace the room module/thermostat with the nest controller and supply a 12v connection to the heat link. I also know to supply the heat link with a 240v connection for power.

Looking at the instructions of the heat link I need to connect call-for-heat (NO), common and satisfied (NC).

The problem I have is that unlike previous versions of the HIU my one has no obvious connections for the above. I have attached the electrical diagram to the HIU - can anyone decipher it at all?

I hoped I could simply use the wires that went to the thermostat, or would that be 'too easy' ?

Really hoping somebody has done this before.

Many thanks

Matt

 

[AndaD]

@MattG07

Hi there and thanks fro reaching out. I'm happy to see your interest in our product. Let's check on this. That's correct, you'll need a 240v connection from the mains to the Heat Link (white receiver) and if you're going to have your thermostat (display) wall mounted, then a 12v wire will be needed from the Heat Link to it. Also, based on the type of boiler you have (system/combi boiler) the wiring can be different, especially if you're going to use it to control your hot water too. Please have a look at the Installation Guide as it will guide you through the whole installation process: https://goo.gle/2pTMYLC

[AlexD]

Hi, I wanted to check in. Do you need any further assistance? If so, make sure to let me know. 

[MattG07]

Hi Alex,

Thanks for helping out - I've read the instructions several times over and think I get that part.

The problem I'm having is connecting the HIU - do I simply connect contact 35 and 36 (as 33 and 34 seem to be power for the original thermostat) for heating to the heat link contacts 2 and 3?

I believe the HIU has hot water on constant.

Many thanks

Matt  

[AlexD]

While I can advise which type of wires you require for each terminal on the Heat Link I can't say for sure which of these are the ones in your system as we are not specialized on different boiler types, and especially as it uses numbers for the markings of their terminals, which are proprietary to the system manufacturer.

I would recommend you get in touch with the system manufacturer as they will know what each terminal means and help you identify the live, neutral and call for heat and any other required terminals and wires or, if possible, get in touch with a Nest Pro if there are any available in your region, as they are installers that are familiar with different heating systems and our thermostat. 

You can use this link here to go to our store page and select the "Find a Nest Pro" option at the bottom. If you are in a different region then the UK, make sure to change the country as well and then select the option. 

[MattG07]

Hi Alex,

I have already contacted Evinox - however they closed their tech support team down some time ago and could only give me a guide for an HIU that isn't mine - funnily enough the one they gave me had call for heat, call for hot water and both common contacts - but they seem to have removed all the labelling on newer systems. 

I will do what you suggested and contact a Nest Pro.

Ta

Matt

[AlexD]

That would probably be best in this case. While we could speculate we don't want to do so when dealing with high voltage and your system. A wiring mistake could damage the thermostat, heating equipment or other devices at the location. It is best to have a professional look at it. 

Keep me posted on how it goes. If something else comes up me or my colleagues will be happy to try and assist in any way we can. 

[CristianC]

Hello again. Just checking in. How's it going with the installation? 

[DragosC]

Since I haven't heard from you in a while, I'll have to close this thread. Should anything else come up, please open another thread and we'll take it from there. Have a good one and stay safe!