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Viessmann 100 Display Issues

Hi there -

My wife and I have spent a lot of time reading through posts here so thanks for any help you can offer!

We recently had a Viessmann 100-W installed, replacing a 25 years old oil boiler that leaked itself to death. Unfortunately, our contractor hasn’t been top-notch and we’ve spent the last couple days fixing some of his work.

We have two heating zones, and the one upstairs - after making loud water gushing sounds - will no longer heat. The Taco circulating pump for the upstairs zone is trying it’s hardest to work, but blinks white, which I believe means arhat there’s air in the system. Not surprising after the gushing sounds heard in the radiators.

So! We read quite a bit on how to fill and purge the system. And when trying to follow the steps to run the bleeding program on the Veissmann, I’m finding that the up arrow won’t work on the display! All the other buttons seem to work just fine, but can’t get the up arrow to respond. I’m wondering if there’s a way to reset the display? Maybe there’s just a bug?

Anyway, any help would be greatly appreciated!


  • Robert O'Brien
    Robert O'Brien Member Posts: 3,537
    The air issue is in the system, not the boiler. There should be a air separator or low loss header with air eliminator that should handle the job after the initial purge, otherwise this be a recurrent problem
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  • dcbraley
    dcbraley Member Posts: 15
    I experienced the same problem with the "UP" arrow before, I powered down the boiler and then re-started it, that cleared it for me.
  • lanem2494
    lanem2494 Member Posts: 11
    dcbraley said:
    I experienced the same problem with the "UP" arrow before, I powered down the boiler and then re-started it, that cleared it for me.
    I’m experiencing this issue with the “UP” arrow on my Vitodens 100W (B1HA) display as well. Powering down the boiler resolves it but only temporarily…15-20 minutes later the it’s non-responsive again. Does anyone know if there is a permanent solution to fix this? It’s a very annoying quirk. 
  • GGross
    GGross Member Posts: 950
    edited January 30

    The up arrow failure was a known manufacturing defect that presents itself in varying degrees. The only permanent solution is a control board replacement. Other than the up arrow not working there should be no other issues running the board. I did try to take one apart to see if there was an easy DIY fix but nothing stuck out to me.