Buderus Logamatic 2107 with Hydro Air

GW

Yes, the black dial is a mechanical device. I'm not sure what you are calling over temp safety limit. The 2107 is serving two functions, it is an outdoor reset control, and it is the control that keeps the boiler from blowing up. The computer is not allowed to act as the high limit for safety reasons. When you program the max temp into the computer, we are assuming that will do the job. If the computer fails, the black knob is there to protect the boiler.

GW

Yes, you got it.
I honestly have never considered what the actual number is if it's cranked all the way to AUT. I'd be quite surprised if it's 230.

At my office/shop we have a G125, and I have the black knob at 140. Basically the black knob (or shall i say dial) is the "i cont care what the computer wants, the boiler is not getting hotter than the black dial setting"

I suppose Buderus adds a small level of confusion when they say AUT which I suspect means Automatic. If they simply typed "MAX" on there, it may be easier for people to digest.

GW

Yes, 6000 Sq ft, 2/3 slab and 1/3 staple up

R Mannino

The boiler puts out 150,000 BTU's The tank if it has 1 1/4" piping is probably a 46 gallon tank and it will only accept 137,000 BTU's that explains the boiler temp rise.

GW

AJ- sure when the tank is cold, not when it's just recovering. Don't care what the manufacturer says!!!