Hi all,

I've used Viessmann 450X signals on my layout, they've been in use for over a year without problems.

However one of my 4500 signals decided it would not operate. That is the motor would not switch when making contact - spark visible so electrical contact is OK.

I removed it and tested on other PSU and same problem.


Reading on Stummi forums it seems there is some history of this problem - they either work forever or they fail within a year or two.

One user reported adding some WD-40 down the signal lever hole on the top and tapping the drive shaft which resolved his problem and perfect since.

https://www.stummiforum....=Viessmann+4500#p1648442


I tried the same technique and found tapping the drive shaft did resolve the problem but not permanently. It will switch a few times and now gets stuck in the Go position (originally it had been stuck in Stop position).

I used Inox instead of WD-40 (much the same and probably more suitable than WD-40) though considering only tapping the drive cylinder restores the motor function, I don't think the Inox has done anything.

As a result I feel my only option is to open up the signal and try and determine the fault (likely wiring?)


Has anyone managed to open a Viessmann 450X series signal without damaging the housing?
Or does anyone have another suggestion for me?

Thanks.

I didn't try Inox until it failed, so it's not the cause of the failure.

I have tested it a lot since with no further changes and it seems to be working reliably again.

Moving forward if it fails again the best option is to just removing the drive and connect the lever mechanism to a servo.