How to switch Viessmann DHW off when immersion is auto on

[Phill Peck]

The problem is your type of system which is rare by comparison to a standard s/y plan

The immersun (similar unit) will interrupt the 240v switching of the cylinder thermostat and supply the immersion.

The problemnisbthat your system uses a cylinder sensor or thermistor not 240v switching.

It's unlikely any company would develop a product to match your system because the payback just isn't there for them.

 

[Agile]

As usual, most informative and helpful replies, giving much food for thought. As I have already said, I am sure someone will come along with such a system very shortly.

Not really because you have got the "wrong" kind of cylinder and not the type specifically designed for integrating solar energy.

Of course yours can be used but needs a little specially designed electronics.

Tony

 

[Phill Peck]

Not sure if it is compatable on the 200 series would be worth a call to tech I would think it can be

I've used these on the 100 range
http://viessmanndirect.co.uk/Catalo...iler-Accessories/Cylinder-Control-Box-7296968

Would need a permanent live to a 240v cyl stat common from boiler, then call goes to this cylinder box along with a neutral. Then which craft inside the box converts the 240v signal to a resistance reading the pcb will register as demand for HW.
Can't see any Reason why this couldn't be wired through the immersun unit

 

[Jackrae]

Tristar
Did you ever get this query resolved . If so how did you achieve it.

 

[Tristar]

No, I've not taken it further due to being too busy. I'm just doing it by adjusting the boiler DHW temp and the iBoost settings to choose timings for the immersion boost to switch on.