External wireless control on Main Combi

[Zochus]

Guys I'm having a struggle here with the wiring of the external thermostat for my Main Combi 30 Eco.

I have purchased Drayton MiTime T710R unit that needs to be wired. Although diagrams are a bit confusing and with me never fitting one previously I could do with a bit of help.

Here are the photos of the diagrams I have in front of me but which now connects to where really.

 

[stem]

You don't mention having any existing room thermostat being connected to the boiler, so I assume there isn't one. If you do have one, the wiring will have been changed from the first photo you post.

Also, I believe that with your boiler, you may well have to open up a 'room sealed' compartment to access the boiler wiring terminals. If so, this is not a DIY job and should be done by a Registered Gas Installer who will make sure that it is properly sealed up again afterwards. Sorry I can't confirm this bit as I am an electrical engineer and not a RGI.

If you can access the boiler wiring without opening up a sealed enclosure, then:

The yellow link between (1) and (2) is removed
Terminal (2) "230v live out" goes to MiTime (1) 'Com' and (L)
Terminal (1) "Switched live in" goes to MiTime (3) 'On'
Terminal (N) goes to MiTime (N)

If you do already have an existing room thermostat, but omitted to mention it, then the wiring to that could go to the MiTime instead. Then you would be able to replace it with the MiTime without disturbing the boiler wiring.

 

[Zochus]

I have sorted the wiring but what is actually meant by room sealed compartment? If you take the two screws holding the front panel so you can open it down its not really separated from anything or sealed in any way.

 

[stem]

Boilers are sealed so that the combustion process is isolated from the room. Air is drawn in from outside via the flue, and the fumes steam etc are also expelled via the flue. Some (not all) boilers, have the wiring terminals located inside the sealed compartment. If a room sealed compartment has to be opened to access the terminals an RGI should carry out checks to make sure it is completely sealed up again afterwards.

 

[Zochus]

It doesn't seem to me as the wiring bit is sealed off in any way. It doesn't also say anything under the cover of the controls or if you remove the controls panel. In total to gain access to necessary wiring it's just 3 screws. 2 holding the front panel and 1 to access the terminal for external thermostat controller

 

[stem]

OK. like I said, it might not be. Some are, some aren't. Only someone familiar with your specific make / model would know.