Has anyone tried to lessen the air on idle with there Keystoker? Will the Kaa-2 combustion fan run with a rheostat? Seems to me there is too much air being pumped into the combustion chamber on Idle for such a small fire, actually cooling the boiler. Any info will be helpful
Thanks, Ed
Does Too Much Air at Idle Cool the KAA-2 Boiler?
With a Kaa-2, there are are few ways to optimize your system: 1) vessel temp, 2) airflow, 3) system design (pump/zone valves/etc). The perfect system would have the coolest water, the minimum air, and the tiniest pump that could do the job. I've pondered or tried all of them after considering the costs and potential returns. Digital controls and variable speed pumps can get pricey. The returns in small residential applications may not be really attractive.
As you may have seen in some of my posts, I've tinkered with my Kaa-2 in all sorts of ways to eek out ever better efficiency or automation. My stoker is now controlled by a tekmar 256 outdoor reset controller. This gizmo is pretty slick and costs about $166 delivered. It continuously monitors outdoor and boiler temperatures and targets an optimum temperature. In a perfect world, the unit would have my little 3-speed Grundfos ($67) running 24/7 and never quite reach the target. It comes pretty close.
As for controlling the combustion fan motor speed, it's possible. Supposedly, those little shielded pole motors lend themselves to variable speed control with ceiling fan-type regulators. My results with this experiment weren't impressive and were kinda noisy. Also, to be truly worthwhile, you would need a device which could automate the speed. It became too complex for me. I'm heating a 2700sq ft house in central NY and providing DHW for a family of 7 with less than 6 tons a year, main thermostat 68-70. Oil b/u kicks in when needed, but it has been less than 20gal all winter.
There is a member, Highlander, who has some slick electrical engineering skills. I think his system is completely automated. You might check his posts too.
As you may have seen in some of my posts, I've tinkered with my Kaa-2 in all sorts of ways to eek out ever better efficiency or automation. My stoker is now controlled by a tekmar 256 outdoor reset controller. This gizmo is pretty slick and costs about $166 delivered. It continuously monitors outdoor and boiler temperatures and targets an optimum temperature. In a perfect world, the unit would have my little 3-speed Grundfos ($67) running 24/7 and never quite reach the target. It comes pretty close.
As for controlling the combustion fan motor speed, it's possible. Supposedly, those little shielded pole motors lend themselves to variable speed control with ceiling fan-type regulators. My results with this experiment weren't impressive and were kinda noisy. Also, to be truly worthwhile, you would need a device which could automate the speed. It became too complex for me. I'm heating a 2700sq ft house in central NY and providing DHW for a family of 7 with less than 6 tons a year, main thermostat 68-70. Oil b/u kicks in when needed, but it has been less than 20gal all winter.
There is a member, Highlander, who has some slick electrical engineering skills. I think his system is completely automated. You might check his posts too.
-
stovepipemike
- Member
- Posts: 1225
- Joined: Sun. Jun. 15, 2008 11:53 am
- Location: Morgantown ,Penna
kenbod~Just a question on the outdoor controller,does it simply control the boiler temperature by acting as a remote thermostat .Is the object to create an ideal temperature differential that would drive heating temperature only enough to do the B.T.U. requirement without excess? Sounds like it might be worthwile. Have you documented any actual savings with use on your Kaa2? Regards, Mike
Kenbod, Thanks for the info. Sounds like my plan of a 2 stage combustion fan won't work if the motor doesn't like a rheostat. It may of just given me more unburnt coal at idle with the lower fan speed. Sounds like the Tekmar is a smart option. Beckett makes one with no outside sensor, I think they call it Heat Manager, they promise at least 10% savings. Do you know anything about, or if this controller would work with the Kaa-2?
Ed
Ed
As far as a fan control goes, I'm not saying it can't be done or that it's not worth it. I am saying that if "off the shelf" technology exists, I haven't found it. Or, it's complicated. Or expensive.
I'm all about maximum return for lowest cost. Kinda like coal. Compared to the convenience of oil or gas, I hate the stuff. But the cost cannot be beat!
Optimized pumps and plumbing save real money. In CNY, where electricity approaches $0.15/kwh, low resistance and little pumps save real money.
The tekmar will save both money and coal (carrying, loading, ash, etc). tekmar has several controls. I got the entry model, the cheapest. It continuously monitors outside and boiler temperatures and targets an optimum. You can tinker with with its programing by changing parameters. I was drawn to better automation for a few reasons: save money and limit temp swings. On really cold days, I could set the unit for 180F and forget it. The thing ran flat out to warm the house. But, temps change and some days are 40F and some nights are 15F. The boiler set for a 10F night at 180F would idle with plenty of burning coal as the day warmed up. Frankly, it would over shoot. The house would be 75F and the basement zone would open to dump the heat to keep the system from over heating. That means wasted coal. The tekmar has significantly limited this.
But tekmar makes several units with lots of bells and whistles. They can even control your pump speed. And automatically turn down the boiler if your house gets warm because its really sunny or because your wife if baking up a storm in the kitchen. They have stuff that can control more than one boiler and set different temps for different reasons (DHW vs baseboard radiator). All their stuff is off the shelf, tested, ready to go. Their stuff is isn't designed for coal, but works well. And their technical support guys have been very helpful in seeing this niche developed. I'll answer any questions I can.
Ken
I'm all about maximum return for lowest cost. Kinda like coal. Compared to the convenience of oil or gas, I hate the stuff. But the cost cannot be beat!
Optimized pumps and plumbing save real money. In CNY, where electricity approaches $0.15/kwh, low resistance and little pumps save real money.
The tekmar will save both money and coal (carrying, loading, ash, etc). tekmar has several controls. I got the entry model, the cheapest. It continuously monitors outside and boiler temperatures and targets an optimum. You can tinker with with its programing by changing parameters. I was drawn to better automation for a few reasons: save money and limit temp swings. On really cold days, I could set the unit for 180F and forget it. The thing ran flat out to warm the house. But, temps change and some days are 40F and some nights are 15F. The boiler set for a 10F night at 180F would idle with plenty of burning coal as the day warmed up. Frankly, it would over shoot. The house would be 75F and the basement zone would open to dump the heat to keep the system from over heating. That means wasted coal. The tekmar has significantly limited this.
But tekmar makes several units with lots of bells and whistles. They can even control your pump speed. And automatically turn down the boiler if your house gets warm because its really sunny or because your wife if baking up a storm in the kitchen. They have stuff that can control more than one boiler and set different temps for different reasons (DHW vs baseboard radiator). All their stuff is off the shelf, tested, ready to go. Their stuff is isn't designed for coal, but works well. And their technical support guys have been very helpful in seeing this niche developed. I'll answer any questions I can.
Ken