Viessmann Boilers Guide

Hi Everyone,

I have a Viessmann Vitodens 100 Boiler that provides heat and hot water. Well, currently I am getting neither, the reset light is flashing red on & off & the pressure is displaying at 0.5. Can I fix it at home or should I call a specialist?

Thanks

Tom

Hi Tom,

You can use a filling loop for increasing the pressure of the boiler 1-1.5 bar. There should be the braided pipe under your boiler somewhere with the small tap on it. This braided pipe should have an isolation valve at it’s both ends, one from the rising cold water main & another one into your pressurized system. Firstly, find all these things. Moreover, sometimes valves have little flexible levers, which are at 90 degrees directly to the pipe once closed & in-line with a pipe when open. You have to open a valve at pressurized system end in a case; it is not open already. Afterward, while watching a pressure meter, gradually open an isolation valve. Allow some water in then, slowly close the isolation valve to order to stabilize the gauge. Repeat this process, until you will get the required pressure for your boiler that it 1-1.5 bar.