Low Temp Aquastat for K42 & K84 Twin-Flo III

I am a homeowner and had 2 kickplate fan units which were not turning on with our boiler. I purchased two low temp aquastats after consulting with an HVAC professional about my problem. I was able to test the units on the plumbing coming to the units, thanks to that plumbing being about the same size as the pipes in the baseboard heaters. What I found is that the aquastats did not react quickly to the change in water temperature, but if I left them and came back after several minutes they would have closed the circuit. So I went ahead and installed them. Installation was easy. For me the most difficult part was getting access to my heating units, which were installed in a way which made access to their electronics difficult. Once in, it was just a matter of replacing the existing standard aquastat by unclipping it, undoing a wire nut and unplugging a lug, then reversing that with the new unit. As soon as I did this, my baseboard heaters started kicking on when the boiler was sending heat through the loop. Full disclosure: As it turned out, the real issue in my case was a disconnected temperature sensor on my modulating outdoor control, which was causing the boiler to send 122F water through the loop. So had that been addressed I never would have bought the low temp aquastats. I still think they will be useful for times when warmer outside temps cause the boiler to send water in the lower temp range, so I have no plans to switch back to the standard units.

Currently going back to job site to replace a 4th aquastat due to defective units right out of the box. First one lasted about a month, now they are defective out of the box. Looking really bad to the customer over this. B-M needs to source a stat from some other manufacturer that will work and is reliable. Last one you could hear an audible click but no contact made. I really don't want to rip this thing out to go with another brand. I've never had trouble like this before with their kicks. If I could spec another aquastat from another manufacturer I'd retrofit it. Working for free and losing customers is not the way to go in this business.