Viessmann weather compensator

[Gerard17]

Hi all am i rite in saying that if I fit a viessmann vitodens 35 kw system boiler with a unvented hot water cylinder and with a weather compensator then the hot water side will take ages to get hot as the temputure in the flow will only be about 40 degrees. So if I fit the 4 pipe system can that only be done with viessmann cylinder as I don't need exspansion vessel or zone valves??

 

[chris watkins]

No you are not right. if it were you could only ever get 30 - 35 deg water in the cylinder.