Several Rivers Brewing Company

We're going to Nationals! Well, our beer is, anyway. Red Wine, our accidental barleywine, got first place in the Strong Ale category at our local judging center for the National Homebrew Competition!

Looking for some advice.... Our main facility uses a cooler as a mash tun, and it works great. The Binney facility is directly heating a kettle as an MLT, and we have overshot FG every time. Recipe should finish at 1.014, ends up at 1.007; another supposed to be 1.012, ended up at 1.003. I suspect mash temp is too low, but when I take temp readings, even after thorough stirring, I get temps anywhere from 145 to 160. Any suggestions that don't involve buying more equipment?