On kstill's issues, I did try to read carefully, but I am unsure if his stoker was running flat out during the problems or not. The radiation and pump flow issues aside, if it was running flat out , and could not keep up, perhaps it needed more air, and maybe more feed? I have read opinions here that say "leave it at the factory setting, they know what they are doing", etc. Bull. Many breakers are passing off barley for rice. It takes more air to burn smaller coal. The grates often leak air around the edges, lost air. A higher feed rate and the req'd add'l air flow to burn it WILL increase the output of the KAA-2. Will you blow more heat up the flue? Yes, but at least you can get all the boiler will give you.
On pins, I agree 100% with Oliver. I am heating 3500 sq ft with a Kaa-2. Although I switch back to my elec tank in single digit weather, I normally make DHW too. I originally pumped the water 24/7 to two fan coil units, cycled the fans as req'd, and the timer and 8124 controlled the stoker. The temp would drop way off after the boiler dropped far enough  to make the 8124 bring the stoker on. Following Oliver's lead, I learned that he is right about more timer pins being the answer for the little boiler.
Now, that said, fellows here [mostly steamup and Sting] convinced me that my setup was less than ideal. I installed zone valves on my two "zones": [two fan/coil units]. I wired the end switches back to the TT terminals in the 8124. So, any time either fan/coil unit runs, the zone valve calls to the stoker, and it runs. I make DHW too. I have pre-heaters that heat the well water on the way to the elec tank. I have a opens on rise aquastat on the line from the well, apx 4" from the 1st preheater. It's also wired back to TT, and closes to cause the stoker to run whenever water is drawn. The zone valves were a huge improvment, but I still run a pile of pins. It's been really cold here [below zero at night], and I've been running 3 sets of 6, and 3 sets of 8 [yes, 42 total]. In warmer temps, I'll drop back to as little as three sets of 6.
p.s. - sorry farrell, this probably doesn't help you.