Kenneth's Blog

Kenneth's Blog

Viessmann 5211

ElectronicsPosted by Kenneth Pallund Tue, December 31, 2013 00:06:21
The 5211 can be modified to switch more reliable.
The capacitor C5 of 220uF can be enlarged - but not too big though, else it will take to long to charge it. I chose another 220uF/25V. Also if it bacame much bigger it would not fit inside the 5211 box. Just solder it parallel to the existing capasitor - positive to positive and negative to negative.
P.S The schematic is of the old 5211 with descrete components. The new are with more SMD components and I have heard its slightly different (but not much - an extra diode and such)

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Posted by Jan Thyregod Mon, September 22, 2014 23:42:32


I have actually noticed that the old 5211/91 has 3K3 resistors for the transistor base, newer versions has a 1K5 resistor....well minw is from 99.