windyhill4.2 wrote:lots to be said for maintaining the mass vs heating up the mass.
I forgot to mention; for best results, after adding pins, turn down your thermostats. Let the boiler come up to hi aquastat temp (180*), or a little higher, before turning thermostats back up. If boiler is not up to temp, you'll continue having the same problem. Don't make the zones fight for BTU's because the boiler is not yet up to temp.oliver power wrote:I'll give you my settings. First off, I'm heating 1700 square feet using 76 feet of 3/4" finned baseboard radiation. I'm heating my place to 73*. So, unless you have a big heat loss, the little Kaa-2 is not too small to heat your 900 square foot house. I'm burning buck size coal. Stoker feed: turn the feed screw all the way clockwise. Then back it off about 3 - 3-1/2 turns. Triple Aquastat: is set 160* Low - 180* high, w/10 differential. Timer: with these temps, I need 3 groups of 5 pins. Being only 900 square feet, 5 pins per group may trigger your high limit aquastat. Then you'll try 3 groups of 4 pins. Maybe add / subtract one or two pins. You get the picture? With the Kaa-2 boiler, you need to maintain a higher, more responsive fire on the carpet. And you do this with timer pins, depending on weather conditions. The Kaa-2 is not engineered to run on the timer, but that's how it has to be run. That's what throws the non-Kaa-2 owners off. On other boilers, the timer is for keeping min fire. As for the Kaa-2, the bigger the fire, the less lag time, which gives the stoker time to ramp up, and take over in these bitter cold temps. If the carpet fire is too big, you'll trip the high limit aquastat. Take out pins to fine tune. Too much lag time, and the boiler drops below the low limit on the triple aquastat, shutting down the circulator, which if I'm reading into this correctly, is your problem. Yes, if you hear water going through the pipes, I too am guessing the noise is air. I'm guessing your problems are; 1.) not enough pins in the timer. 2.) Air in the system. 3.) Too much heat loss. 4.) As Sting said, slowing down the flow gives time for heat to be absorbed by the finned baseboard radiation. Let us know how you make out. Oliver
As the weather warms, he'll be taking pins back out of timer. His hi limit aquastat will let him know if he's maintaining too hi of boiler temps. It's just during these cold temps he needs to run on the timer. He'll find by controlling his fire on the carpet, he'll be more comfortable, as well as more efficient. He's not wasting BTU's. They will be used. Why else do you think Keystoker sends about 30 timer pins with the Kaa-2? It's not because they have extras.Pacowy wrote:windyhill4.2 wrote:lots to be said for maintaining the mass vs heating up the mass.
I understand this may be a strategy for trying to keep an undersized boiler out of a hole it can't escape, but in the bigger picture isn't this saying that an undersized boiler may not let you achieve the efficiency benefits of setbacks? That seems like more like a constraint or cost imposed by the undersized boiler, and not anything that is meritorious on its own..
Hi Mike, During the colder months, the Kaa-2 needs to maintain a bigger/hotter "idle" fire on the carpet by adding timer pins. I call it riding on the timer because that's what it is doing. Not a lot, just a little. The bigger idle fire reduces lag time. Reduce the lag time of the Kaa-2, and it runs like a Swiss Watch. Otherwise, yes, you are correct. The triple aquastat controls the stoker. The problem the original poster has is too much lag time. With the small water capacity of the Kaa-2, the boiler temp drops below the low limit of the aquastat before the stoker is ramped up to speed. This shuts off the circulator. Maintaining a bigger idle fire takes care of that problem. And you do that by adding timer pins. OliverPacowy wrote:I don't see how timer pins are the real problem. When the unit is running under a heavy load, it spends less time running on the timer in the first place, and in any case it shouldn't take that long to fire back up. Zones fighting each other for btu's and "better" performance when the efficiency of idling is sacrificed to me point to the same root problem - insufficient boiler size. As long as the boiler is sized to power the installed radiation to which it is attached (plus DHW load), zones won't fight each other for btu's and the boiler can rest in a true and efficient idle when stoker output is not needed. The various ad hoc remedies discussed in this thread and others may mitigate some of the symptoms, but they don't solve the underlying problems that can be created by reliance on boilers that are undersized relative to the installed radiation (plus DHW load).
P.S. To be clear, I'm not saying the installed radiation should not be sized carefully according to heat loss or other relevant considerations. I'm saying that once you have fixed the amount of radiation, you create your own problems if you try to power it with a boiler whose capacity to produce btu's is less than the rate at which the radiation delivers the btu's (plus DHW load). With all of the references made to the need for system "balance", this is a fundamental cause of imbalance that appears to be overlooked by the proponents of undersized boilers.