Problems with kaa-2 temps.

Re: Problems with kaa-2 temps.

PostBy: kstills On: Sun Jan 26, 2014 8:33 am

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


I won't speak to the operation of the Kaa2, because I don't have one and uncharateristically I won't offer an opinion.... ;)

however, as to the rest of this post:

http://www.homedepot.com/catalog/pdfIma ... 9a77fc.pdf

page 8 gives the btuh of 1ft 3/4 inch slant fin tubing. So lets say that you're working your Kaa2 to the max and deliveryin 200f water to the radiators, your heat output total is going to be

810 (btuh per ft) X 76(lin ft radiation) = 61560 btuh into the dwelling.

That's it. Doesn't matter if theres a small fan blowing on the boiler ( :P ), all you get is that amount of heat.

If you look at the chart, you'll see they list btuh in two rows, one at 1gpm, one at 4 gpm. And the 4gpm output is higher than the 1gpm. That's because of this bit that I ran across after posting some unfortunate comments about system balance, then deciding that maybe I should go back and figure out what it was:

http://www.caleffi.us/en_US/caleffi/Det ... s_8_us.pdf

In that rather long book you'll find this bit:

The flow rate through each heat emitter also affects its
heat output. The following principles will always apply:
• The faster a heated fluid passes through a heat
emitter, the greater the rate of heat transfer, when all
other conditions are equal.
• From the standpoint of heat transfer only, there is
no such thing as flow moving too fast through a heat
emitter.
Some heating professionals instinctively disagree with
the second principle. They argue that because the water
moves through the heat emitter at a higher speed, it has
less time in which to release its heat. However, the time
a given water molecule stays inside the heat emitter is
irrelevant in a system with a circulating fluid.
The increased heat output at higher flow rates is the
result of improved convection between the fluid and
the interior wetted surfaces of the heat emitter. The
faster the fluid moves, the thinner the fluid boundary
layer between the inside surface of the heat emitter
and the bulk of the fluid stream. The thickness of this
boundary layer determines the resistance to heat flow.
The thinner the boundary layer, the greater the rate of
heat transfer.
Another way of justifying this principle is to consider the
average water temperature in the heat emitter at various
flow rates. Consider the example shown in figure 2-2
where water at 180ºF enters the coil of an air handler unit
at different flow rates.
As the flow rate through the coil increases, the temperature
difference between its inlet and outlet decreases. This
means that the average water temperature in the coil
increases, and so does its heat output. This holds true
for all other hydronic heat emitters, such as radiant panel
circuits, panel radiators and baseboard.
It might seem intuitive to assume that heat transfer from
a heat emitter increases in proportion to flow rate through
it (i.e., doubling the flow rate through the heat emitter
would double its heat output). However, this is not true.


So, faster flow rate, once the boiler reaches the high limit will deliver more btu to the dwelling. What we don't know is if the circulator is running continuously, or shutting off.

Finally, there's this:

http://www.builditsolar.com/References/ ... atLoss.htm

Insert a 30by30 house, 9 foot walls, 136 sq ft of windows and doors with two occupants, and minimal insulation and you'll end up losing ~47kbtu hour at 0deg f. Rough, but absent more details it serves to illustrate what the OP is up against trying to heat his dwelling.
kstills
 
Stoker Coal Boiler: WL 110
Stove/Furnace Make: Leisure Line

Re: Problems with kaa-2 temps.

PostBy: kstills On: Sun Jan 26, 2014 8:40 am

KLook wrote:
If he's running 3/4 inch copper, 100 feet of pipe equals 4.1 gallons of water required. Give another 100 feet for the spaghetti in the basement, and your using 24 gallons of hot water to feed 8 gallons worth of piping.


If you are correct in the math, that is 1/3 the capacity of his boiler. You don't think pushing cold water into the vessel at a rate of ? GMP will overrun the unit before the stoker can even get started? My VF3000 would cool all the say down from 200 to 150 before the stoker would start to run! Then it would settle in at about 140 and just run n run n run. 8 gal. of water in a 50 gal system would not be to bad. And I remember being chastised by the fabulous Sting for having the return water start my stoker! But it still works that way with cube relays because when the 2 cast iron radiators in the basement call for heat, you better get that coal pushing right now! The sensor to start the unit up is on the top and it is to late when it realizes ITS COLD. Plus I slowed the flow down on those zones to give the stoker more time to get ramped up.
I can only report what has worked for me with an undersized boiler.
It seems the speed/gmp of his circulator wood be important and maybe throttle it down a little to help the stoker catch up.

Kevin



Maybe, all I have to go by wrt to this issue is my own system. I am running a boiler with 16% of the total capacity of the system being heated, so to me having a system that has 66% of the total capcity being heated seems like a lot.

From a dead stop, my unit takes a looooong time to get everything up to temp, which is why I don't use the programmable tstat anymore. Once it's going, with the tstat differential set to 0.5 degs, it runs great.
kstills
 
Stoker Coal Boiler: WL 110
Stove/Furnace Make: Leisure Line

Re: Problems with kaa-2 temps.

PostBy: oliver power On: Sun Jan 26, 2014 10:28 am

kstills wrote:
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


I won't speak to the operation of the Kaa2, because I don't have one and uncharateristically I won't offer an opinion.... ;)

however, as to the rest of this post:

http://www.homedepot.com/catalog/pdfIma ... 9a77fc.pdf

page 8 gives the btuh of 1ft 3/4 inch slant fin tubing. So lets say that you're working your Kaa2 to the max and deliveryin 200f water to the radiators, your heat output total is going to be

810 (btuh per ft) X 76(lin ft radiation) = 61560 btuh into the dwelling.



If you look at the chart, you'll see they list btuh in two rows, one at 1gpm, one at 4 gpm. And the 4gpm output is higher than the 1gpm. That's because of this bit that I ran across after posting some unfortunate comments about system balance, then deciding that maybe I should go back and figure out what it was:

http://www.caleffi.us/en_US/caleffi/Det ... s_8_us.pdf

In that rather long book you'll find this bit:

The flow rate through each heat emitter also affects its
heat output. The following principles will always apply:
• The faster a heated fluid passes through a heat
emitter, the greater the rate of heat transfer, when all
other conditions are equal.
• From the standpoint of heat transfer only, there is
no such thing as flow moving too fast through a heat
emitter.
Some heating professionals instinctively disagree with
the second principle. They argue that because the water
moves through the heat emitter at a higher speed, it has
less time in which to release its heat. However, the time
a given water molecule stays inside the heat emitter is
irrelevant in a system with a circulating fluid.
The increased heat output at higher flow rates is the
result of improved convection between the fluid and
the interior wetted surfaces of the heat emitter. The
faster the fluid moves, the thinner the fluid boundary
layer between the inside surface of the heat emitter
and the bulk of the fluid stream. The thickness of this
boundary layer determines the resistance to heat flow.
The thinner the boundary layer, the greater the rate of
heat transfer.
Another way of justifying this principle is to consider the
average water temperature in the heat emitter at various
flow rates. Consider the example shown in figure 2-2
where water at 180ºF enters the coil of an air handler unit
at different flow rates.
As the flow rate through the coil increases, the temperature
difference between its inlet and outlet decreases. This
means that the average water temperature in the coil
increases, and so does its heat output. This holds true
for all other hydronic heat emitters, such as radiant panel
circuits, panel radiators and baseboard.
It might seem intuitive to assume that heat transfer from
a heat emitter increases in proportion to flow rate through
it (i.e., doubling the flow rate through the heat emitter
would double its heat output). However, this is not true.


So, faster flow rate, once the boiler reaches the high limit will deliver more btu to the dwelling. What we don't know is if the circulator is running continuously, or shutting off.

Finally, there's this:

http://www.builditsolar.com/References/ ... atLoss.htm

Insert a 30by30 house, 9 foot walls, 136 sq ft of windows and doors with two occupants, and minimal insulation and you'll end up losing ~47kbtu hour at 0deg f. Rough, but absent more details it serves to illustrate what the OP is up against trying to heat his dwelling.
That's it. Doesn't matter if theres a small fan blowing on the boiler ( :P ), all you get is that amount of heat. What does air have to do with boilers??? Air takes heat from stoves. Water takes heat from boilers.
oliver power
 
Stoker Coal Boiler: KEYSTOKER Kaa-2
Hand Fed Coal Stove: Hitzer 50-93 & 30-95, Vigilant (pre-Vigilant-II)
Baseburners & Antiques: MANY (Mostly when burning wood)
Stove/Furnace Make: HITZER / KEYSTOKER
Stove/Furnace Model: 50-93 & 30-95 , Kaa-2

Visit Lehigh Anthracite

Re: Problems with kaa-2 temps.

PostBy: lsayre On: Sun Jan 26, 2014 10:44 am

In the end if you pull out more heat you burn more coal. That said, it's good to know that I can get more BTU's out of each foot of my fintube baseboards by speeding up the water flowing through them, as at 550 BTU's per foot and with only 112 feet of baseboards between the upstairs and the basement (not counting 26 feet of baseboard in the garage) I only have enough capacity for delivering 61,600 BTU's in the house proper. If by cranking up my 3 speed circulator I can up that to say 600 BTU's per foot, that at least gives me 67,200 BTU's. It's not much, but it's something.

I just calculated that at 550 BTU's per foot of HW baseboards my house (excluding the heated garage) was designed to deliver only 28 BTU's per square foot of floorspace. Sufficient HW baseboards to deliver 35 BTU's per square foot is better for when it gets really cold outside.
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Anthracite Pea
Other Heating: Resistance Boiler (if I ever get it fixed)

Re: Problems with kaa-2 temps.

PostBy: KLook On: Sun Jan 26, 2014 10:54 am

Oliver, that is a reference to another post we hashed out about fans blowing on a hot stove. Little humor.....
I disagree with kstills interpretation. It assumes that the source of 180 degree water remains constant. Of course you will get more heat out of the higher gpm with a constant supply. But at the higher gmp, his little k-aa2 is being overwhelmed with the cold water. I may not have a k-aa2, but my Harman is very similar. I he does not have a bypass loop, only the water in the top of the boiler is up to temp. Granted, it might not be much cooler, but as soon as the circ kicks in, it is cold right now.
I just checked and the max flo rate for the 007 taco is 23 gpm. Lets assume half that for giggles and that means that in 2 minutes all the water in the boiler has been moved out. That means in 2 minutes, you are already recirculating cold water unless you think that little stoker is magic. Slow it down, get a storage tank, get it stoking on call.

Kevin

and use Olivers advice about using more pins.
KLook
 
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Stove/Furnace Make: Harman (Back In Maine)
Stove/Furnace Model: VF 3000

Re: Problems with kaa-2 temps.

PostBy: kstills On: Sun Jan 26, 2014 11:13 am

KLook wrote:Oliver, that is a reference to another post we hashed out about fans blowing on a hot stove. Little humor.....
I disagree with kstills interpretation. It assumes that the source of 180 degree water remains constant. Of course you will get more heat out of the higher gpm with a constant supply. But at the higher gmp, his little k-aa2 is being overwhelmed with the cold water. I may not have a k-aa2, but my Harman is very similar. I he does not have a bypass loop, only the water in the top of the boiler is up to temp. Granted, it might not be much cooler, but as soon as the circ kicks in, it is cold right now.
I just checked and the max flo rate for the 007 taco is 23 gpm. Lets assume half that for giggles and that means that in 2 minutes all the water in the boiler has been moved out. That means in 2 minutes, you are already recirculating cold water unless you think that little stoker is magic. Slow it down, get a storage tank, get it stoking on call.

Kevin

and use Olivers advice about using more pins.


Well, that brings us back to this quote from the OP:

Water is definitely circulating. I can hear and feel it running through the pipes. The return water is less hot than the water coming from the circulator.


And again, I have no idea what 'less hot' is, although I assume 'less hot' is still heated and not cold. And he still hasn't told us if the circulator runs continuously or not.
kstills
 
Stoker Coal Boiler: WL 110
Stove/Furnace Make: Leisure Line

Re: Problems with kaa-2 temps.

PostBy: oliver power On: Sun Jan 26, 2014 11:17 am

lsayre wrote:In the end if you pull out more heat you burn more coal. That said, it's good to know that I can get more BTU's out of each foot of my fintube baseboards by speeding up the water flowing through them, as at 550 BTU's per foot and with only 112 feet of baseboards between the upstairs and the basement (not counting 26 feet of baseboard in the garage) I only have enough capacity for delivering 61,600 BTU's in the house proper. If by cranking up my 3 speed circulator I can up that to say 600 BTU's per foot, that at least gives me 67,200 BTU's. It's not much, but it's something.

I just calculated that at 550 BTU's per foot of HW baseboards my house (excluding the heated garage) was designed to deliver only 28 BTU's per square foot of floorspace. Sufficient HW baseboards to deliver 35 BTU's per square foot is better for when it gets really cold outside.
I'm not a hydronics man. I did however, design my whole system, which performs excellent. Yes, a bigger flow will deliver more BTU's by volume. A slower flow allows more BTU's to be absorbed at the finned baseboard radiation, which transfers more heat to the living space. I actually read that in my hydronics book. But, like Sting says; Speed up the flow, and see what happens. You can always slow it down. Yes, better to have too much finned baseboard, than not enough. The trick is to have it balanced out so the house is the same temp throughout. If one room has more radiation than the other, one room is going to be warmer than the other. Of course, that's in theory, with both rooms being identical, and radiation in both rooms have the same water temp going in. In reality, If piped in series, you may want an extra foot or so of radiation in the second room, due to the water coming out of the first room being cooler. And it goes on & on. A real science behind it all. Then there's the ART of making it all look good (If that matters).
oliver power
 
Stoker Coal Boiler: KEYSTOKER Kaa-2
Hand Fed Coal Stove: Hitzer 50-93 & 30-95, Vigilant (pre-Vigilant-II)
Baseburners & Antiques: MANY (Mostly when burning wood)
Stove/Furnace Make: HITZER / KEYSTOKER
Stove/Furnace Model: 50-93 & 30-95 , Kaa-2

Re: Problems with kaa-2 temps.

PostBy: oliver power On: Sun Jan 26, 2014 11:34 am

KLook wrote:Oliver, that is a reference to another post we hashed out about fans blowing on a hot stove. Little humor.....
I disagree with kstills interpretation. It assumes that the source of 180 degree water remains constant. Of course you will get more heat out of the higher gpm with a constant supply. But at the higher gmp, his little k-aa2 is being overwhelmed with the cold water. I may not have a k-aa2, but my Harman is very similar. I he does not have a bypass loop, only the water in the top of the boiler is up to temp. Granted, it might not be much cooler, but as soon as the circ kicks in, it is cold right now.
I just checked and the max flo rate for the 007 taco is 23 gpm. Lets assume half that for giggles and that means that in 2 minutes all the water in the boiler has been moved out. That means in 2 minutes, you are already recirculating cold water unless you think that little stoker is magic. Slow it down, get a storage tank, get it stoking on call.

Kevin

and use Olivers advice about using more pins.
I wondered if that was humor. Figured you'd let me know; Computers???? Yes, I went back in the thread; He does have a bypass loop.
oliver power
 
Stoker Coal Boiler: KEYSTOKER Kaa-2
Hand Fed Coal Stove: Hitzer 50-93 & 30-95, Vigilant (pre-Vigilant-II)
Baseburners & Antiques: MANY (Mostly when burning wood)
Stove/Furnace Make: HITZER / KEYSTOKER
Stove/Furnace Model: 50-93 & 30-95 , Kaa-2

Re: Problems with kaa-2 temps.

PostBy: KLook On: Sun Jan 26, 2014 11:42 am

The other way to adjust output of the fin tubing is close down the opening on the cabinet itself. Just like having dirty fins.
I think Sting is all about balance, not necessarily high or low flow, but the proper flow to the proper radiation with the proper supply. If you are at the fringes of this "proper" thing, as I found myself at because I am not a hydronics guy either, you listen, read, and learn about how to manipulate what you have. Then observe your results in the real world. I made it work and it works well, because of this excellent forum. 8-)

Kevin
KLook
 
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Stove/Furnace Make: Harman (Back In Maine)
Stove/Furnace Model: VF 3000

Re: Problems with kaa-2 temps.

PostBy: lsayre On: Sun Jan 26, 2014 12:01 pm

I agree that in the OP's case slowing down the flow seems to be the right idea.

In my case, with a house that was heated for years with only a 22.5 KWH (76,770 BTU/Hr. input/output) resistance boiler, and with just enough length of fintube baseboards to properly utilize that same output level (138 ft of baseboards if I add in the 26 ft of garage baseboard) my 130K BTU/Hr. gross input and (assuming 70% efficiency) roughly 91K BTU/Hr. net output AHS S-130 Coal Gun boiler is a bit over sized to the task at hand, so increasing the flow would not likely hurt me with heat delivery and may help on the coldest of days, but in the OP's case of having a properly sized to perhaps a bit undersized boiler, slowing down the flow to the baseboards so the boiler is not overwhelmed by the returning cold water is certainly worth a try.
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Anthracite Pea
Other Heating: Resistance Boiler (if I ever get it fixed)

Re: Problems with kaa-2 temps.

PostBy: KLook On: Sun Jan 26, 2014 12:15 pm

I am reminded of Stings biting criticism, pump longer periods of time at lower temps to reduce temp swings and have more even comfortable heat, pump enough energy to satisfy the demand over longer periods increases efficiency, (less idling) This requires adjusting the temps to the conditions at hand, outside reset maybe. But in this case, the K-aa2 cannot just ram out enough btu's to keep up with the return temps at the flow rate it is facing. I would have burning coal right to the end of the ramp and the air pushing flame all the way to the top, first. Then slow down my water, insulate the pipes to the baseboard and back to the boiler to keep it all in, we didnt ask how much his basement is sucking out of the unit and pipes. Get through this cold snap and either replace it with a bigger unit, supplement with space heaters, or do all the things others have suggested here to enhance what he has. It looked like the install could use a little cleaning up and there is still the question of air in the system.

Kevin
KLook
 
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Stove/Furnace Make: Harman (Back In Maine)
Stove/Furnace Model: VF 3000

Re: Problems with kaa-2 temps.

PostBy: oliver power On: Sun Jan 26, 2014 12:16 pm

KLook wrote:The other way to adjust output of the fin tubing is close down the opening on the cabinet itself. Just like having dirty fins.
I think Sting is all about balance, not necessarily high or low flow, but the proper flow to the proper radiation with the proper supply. If you are at the fringes of this "proper" thing, as I found myself at because I am not a hydronics guy either, you listen, read, and learn about how to manipulate what you have. Then observe your results in the real world. I made it work and it works well, because of this excellent forum. 8-)

Kevin
Yes, same here Kevin. That's why we're HOOKED. You know, I went back to page one again. His boiler dropped to (I think it was below) 140*. That would shut off his circulator, and he's dead in the water, till boiler temp comes back up. Meanwhile, his house cools off.......and it never got warm to begin with. Once the boiler reaches temp again, the same thing happens again. That's how it works. With a bigger fire on the carpet, it gives the stoker time to get cranked up before the water temp reaches low limit, shutting off circulator. Yet, a lower setting on the triple aquastat allows the circulator to circulate cooler water, which is why his room temps are higher with lower aquastat setting. It might be cooler water but, it's better than no water. My Kaa-2 would do the exact same thing. And so does anyone elses Kaa-2. The simple fix is to add timer pins. He needs to have a bigger fire on the carpet. If he had a bigger fire on the carpet, and the stoker was able to catch up, and take over before the low water temp shut down the circulator, he'd have no problems. And lots of heat. In these cold temps, the Kaa-2 has to be run on the timer. I'm surprised other Kaa-2 owners haven't chimed in here. We all have the same problem, which isn't a problem at all if you know how to run the little boiler. I think if he simply added pins, he'd be running around his house in under shorts. In any case, we want to hear from him. We want results. Oliver
oliver power
 
Stoker Coal Boiler: KEYSTOKER Kaa-2
Hand Fed Coal Stove: Hitzer 50-93 & 30-95, Vigilant (pre-Vigilant-II)
Baseburners & Antiques: MANY (Mostly when burning wood)
Stove/Furnace Make: HITZER / KEYSTOKER
Stove/Furnace Model: 50-93 & 30-95 , Kaa-2

Re: Problems with kaa-2 temps.

PostBy: KLook On: Sun Jan 26, 2014 12:27 pm

I had mine set to kick in the gas boiler at a higher temp then that. I learned that it took to long to recover with 50 gal of water in my Harman. I think about 160 is where I have it. And I am closer to 200(or more) for my normal high in the dead of winter. I did call my son yesterday and he reports that the unit is working great. Even with the addition of more radiation before I moved out, and the fact he has not run the gas fireplace because of cost, it has been able to keep up. For me, it was about getting control of flow rates to certain radiation types, I have pex in concrete, baseboard, cast iron radiators, and 2 toe kick heaters. Just having all baseboard simplifies things a bunch.

Kevin
KLook
 
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Stove/Furnace Make: Harman (Back In Maine)
Stove/Furnace Model: VF 3000

Re: Problems with kaa-2 temps.

PostBy: Carbon12 On: Sun Jan 26, 2014 12:29 pm

At this point, running electric space heaters,....even a bunch of them, would be cheaper than heating with fuel oil or propane. If his little boiler works fine in a normal winter and output has been maximized, the space heater solution would be the least expensive solution in the short term, at least.
Carbon12
 
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace

Re: Problems with kaa-2 temps.

PostBy: oliver power On: Sun Jan 26, 2014 12:29 pm

KLook wrote:I am reminded of Stings biting criticism, pump longer periods of time at lower temps to reduce temp swings and have more even comfortable heat, pump enough energy to satisfy the demand over longer periods increases efficiency, (less idling) This requires adjusting the temps to the conditions at hand, outside reset maybe. But in this case, the K-aa2 cannot just ram out enough btu's to keep up with the return temps at the flow rate it is facing. I would have burning coal right to the end of the ramp and the air pushing flame all the way to the top, first. Then slow down my water, insulate the pipes to the baseboard and back to the boiler to keep it all in, we didnt ask how much his basement is sucking out of the unit and pipes. Get through this cold snap and either replace it with a bigger unit, supplement with space heaters, or do all the things others have suggested here to enhance what he has. It looked like the install could use a little cleaning up and there is still the question of air in the system.

Kevin
Here's the problem with the Kaa-2. It has a small water capacity. The BTU's in the water get used up long before the stoker catches up (min fire). Once the stoker catches up, it'll ram out all the heat you need. She might be running flat out, but she'll keep cranking heat. He needs a bigger fire on the carpet in order to carry through while the stoker is catching up. The bigger the fire, the shorter the catch up. Yet, he needs to not continually trip the high limit aquastat. There is a balance he has to find. At least he'll be warm finding it. Running flat out, my Kaa-2 holds 180* water while heating my 1700 square foot house, in below zero temps, with the wind howling.
Last edited by oliver power on Sun Jan 26, 2014 12:57 pm, edited 2 times in total.
oliver power
 
Stoker Coal Boiler: KEYSTOKER Kaa-2
Hand Fed Coal Stove: Hitzer 50-93 & 30-95, Vigilant (pre-Vigilant-II)
Baseburners & Antiques: MANY (Mostly when burning wood)
Stove/Furnace Make: HITZER / KEYSTOKER
Stove/Furnace Model: 50-93 & 30-95 , Kaa-2

Visit Lehigh Anthracite