Viessmann 100-W System With Evohome

[IND_Nick]

Morning,

I have a job later this week with the above , Viessmann Vitodens System boiler. It has a 4 pipe setup with internal diverter and at present there is a wireless thermostat/programmer controller in the hallway.
Customer wants a Honeywell Evohome System and I just wondered if I can wire this into the boiler to continue using the 4 pipe system and internal diverter, or do I need to pipe CH flow into a S Plan and just cap the DHW Flow/Return as I can only see 1 L and N available so assume this is for a 240v Heating control.
Any advice appreciated, thanks.

 

[Desktop987456]

1 L and N available so assume this is for a 240v Heating control.

Correct. I have a heat only boiler and I have attached thermostat wire here.

 

[Gasmk1]

i like the 4 pipe I would use weather comp rather than evohome and fit the kit for hot water. But if the customer wants evohome. Rather defeats the object of the 4 pipe system doesn’t it.

 

[IND_Nick]

Just spoke to Viessmann and they do a module that provides a 240v connection for the DHW so can all be wired up and remain with the 4 pipe setup.
The Evohome is because they work from home so want to zone the house, it's a semi that been extended on to extension heating pipes are a mess unfortunately as I'd normally recommend zoning for floors with weather compensation.

 

[Ben-gee]

Working from home and of course they can’t just walk around and shut a few rads down, then open them up later!! 🫣