Buderus gb142 - Too High Supply Temp

Hey all.....I was getting an "OY" error message on my Buderus GB142 - supply side water temp exceeding 199 degrees.....my heating guy replaced the pump for the DHW with a larger pump and it has not gotten the "OY"...it reaches 196 which I think is still high....wondering if this was truly the problem or the larger pump is somehow masking the real problem...i.,e supply sensor going bad? Anyone know would a supply sensor give false readings or would it just completely fail?

I have 4 zones - DHW, Air Handler zone, basement zone and garage zone....not using any of the last 3 for several months because it was summer....

Any ideas would be appreciated....

Too high a pump speed can cause turbulance. Did you use the primary/secondary loop setup supplied with the boiler? The tech support at Buderus is pretty good, have you given them a call? The boiler goes to max heat mode when the IWH calls for heat; otherwise, it runs at the normally lower temps dictated by the outdoor reset and controller settings.

Yea, I'd be looking at the re-set controller.

I don't have the outdoor reset/controller....unit was installed in 05'.........I did a test last night, called for heat for 1st level....if I have the temp set to AUX it goes to
194.....if I turn it to 170 it only heats the water to 155, so like 15 degrees short of the temp set.....

I'll also reachout to Buderus....

Thanks

Let us start with a factory certified Buderus technician equipped with an outdoor reset control (not condensing boiler should be without one and most come in the box). Next lets have the professional set up this high efficiency condensing boiler for your system and finish by having him use his combustion analyzer to assure an clean burn, lower fuel bill and long reliable life.

Condensing boilers are not a DIY project nor an good subject for guess-as-you-go blogs.

Saw you drive by Kowolski's in Woodbury this a.m....was thinking, maybe I will call them to take a look at my boiler as another pair of eyes (install and all service has been by factory trained Buderus techs btw).....after your ego above, I don't think I will be calling......

I was simply asking some questions in order for me to understand it more because I am interested in the technology, etc.