Problems With KAA-2 Temps.

Stoker Coal Boilers automatically feed the coal and have controls and pumps just like any conventions boiler. They are intended to be used as a primary heat and often have domestic hot water coils as an added bonus. They can be set up independently or in dual sytem with your existing oil/gas boiler. They can accommodate both hot water base board or steam plumbing.
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farrell2k
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Posts: 217
Joined: Sun. Nov. 11, 2012 4:38 pm
Stoker Coal Boiler: Kaa2
Stove/Furnace Make: Keystoker
Stove/Furnace Model: KA2
Location: Perkasie Pa.

Post Fri. Jan. 24, 2014 1:01 pm

Maybe it has something to do with the extreme cold, but my kaa-2 doesn't seem up to the task this year. I can't get my house past 68* no matter what. The past two years I easily maintained 72*. I cleaned the flu and under the grates and opened a few clogged grate holes and oiled/wiped off my squirrel cage fan as instructed by Keystoker, who told me that the temps were likely not rising because of the cold, but I am only heating 900 sq ft (hot water bb and DHW coil), although I do not have any insulation. My coal feed is good. I have had it almost pushing hot coals off the grate, so I guess the pusher is working fine.

I wonder if the issue is with the aquastat. The previous two years it was set to 140L/160H Diff 10. Keystoker told me 140L was too low, so I have it set to 160L/180H Diff 10. The problem with that is that the boiler will get up to almost 160 but the circulator barely kicks, so my tstat never gets above 64*. If I set the Lo to 140 at least I can get to 67/68. I have noticed that when the boiler gets up to temp and the circulator does kick on, temps drop to 140 and I have to wait a while for it to go back up again ( too long) which ends up making the house cold.

I appreciate any ideas to figure out what's wrong. If this helps, here are some pics.
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Carbon12
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Posts: 2230
Joined: Tue. Oct. 11, 2011 6:53 pm
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace
Location: Harrisburg, PA

Post Fri. Jan. 24, 2014 1:03 pm

Try a diff of 15
No matter where you go,......there you are.

kstills
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Posts: 639
Joined: Tue. Jan. 18, 2011 6:41 am
Stoker Coal Boiler: WL 110
Stove/Furnace Make: Leisure Line
Location: New Britain, PA

Post Fri. Jan. 24, 2014 1:06 pm

How much mass in the system, what is the boiler capacity?

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Carbon12
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Posts: 2230
Joined: Tue. Oct. 11, 2011 6:53 pm
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace
Location: Harrisburg, PA

Post Fri. Jan. 24, 2014 1:08 pm

If increasing the diff to 15 doesn't improve things raising the low to 170 and high to 190 in this cold weather at least might help
No matter where you go,......there you are.

kstills
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Posts: 639
Joined: Tue. Jan. 18, 2011 6:41 am
Stoker Coal Boiler: WL 110
Stove/Furnace Make: Leisure Line
Location: New Britain, PA

Post Fri. Jan. 24, 2014 1:10 pm

Carbon12 wrote:If increasing the diff to 15 doesn't improve things raising the low to 170 and high to 190 in this cold weather at least might help
What's odd is that his tstat is coming on at all. If he had a situation where he was maxed for output, he should be running full tilt without letup.

That boiler shouldn't be shutting off if he's only going up to ~66deg.

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Carbon12
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Joined: Tue. Oct. 11, 2011 6:53 pm
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace
Location: Harrisburg, PA

Post Fri. Jan. 24, 2014 1:16 pm

I was reading it that the circ would turn off below low limit before the demand would be met, the house would cool, circ would come back on at low limit and then the cycle would repeat.
No matter where you go,......there you are.

kstills
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Posts: 639
Joined: Tue. Jan. 18, 2011 6:41 am
Stoker Coal Boiler: WL 110
Stove/Furnace Make: Leisure Line
Location: New Britain, PA

Post Fri. Jan. 24, 2014 1:33 pm

Carbon12 wrote:I was reading it that the circ would turn off below low limit before the demand would be met, the house would cool, circ would come back on at low limit and then the cycle would repeat.
The problem with that is that the boiler will get up to almost 160 but the circulator barely kicks, so my tstat never gets above 64*. If I set the Lo to 140 at least I can get to 67/68. I have noticed that when the boiler gets up to temp and the circulator does kick on, temps drop to 140 and I have to wait a while for it to go back up again ( too long) which ends up making the house cold.


Maybe, I'm reading this that the circulator is kicking off when the tstat calls for heat the the return drops the water in the boiler below the differential temp of the low limit. Then while the boiler is building back to temp, the house cools down.

Which would mean that the boiler should never shut off, and unless he has a really high mass system, eventually he should reach an equilibrium with the water in the system and then continue to heat the water until it hits the temp of the low limit of the boiler.

The only way that wouldn't happen is if A) the aquastat is messed up, or B) he loses so much heat that the water in the system is constantly cooling off faster than the boiler can heat it.

Or C) I don't know what I'm talking about.... :lol:

Reading it again, I'm wondering what he means by 'the circ barely kicks'...

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Carbon12
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Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace
Location: Harrisburg, PA

Post Fri. Jan. 24, 2014 1:36 pm

The KAA2 is only 24 gallons
No matter where you go,......there you are.

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KLook
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Posts: 3631
Joined: Sun. Feb. 17, 2008 1:08 pm
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Other Heating: Gas boiler backup/main
Stove/Furnace Model: VF 3000
Location: Chattanooga, Tenn

Post Fri. Jan. 24, 2014 1:38 pm

I think he means that it hardly runs before the unit shuts down to heat back up again. Sounds like the flo is overwhelming the boilers ability to heat back up. I reduced the flo in my boiler to give it a fight chance plus installed a bypass.

Kevin

farrell2k
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Posts: 217
Joined: Sun. Nov. 11, 2012 4:38 pm
Stoker Coal Boiler: Kaa2
Stove/Furnace Make: Keystoker
Stove/Furnace Model: KA2
Location: Perkasie Pa.

Post Fri. Jan. 24, 2014 1:43 pm

Carbon12 wrote:I was reading it that the circ would turn off below low limit before the demand would be met, the house would cool, circ would come back on at low limit and then the cycle would repeat.
The stove gets up to temperature then the circulator kicks in. The boiler temp drops when the hot water leaves and then the circulator stops until the boiler satisfies the low setting and the cycle starts again. , room temp drops. Can't get above 64 in the room.

I do have the a stat set to 160/180/15 as carbon suggested. I will d see what that does. Thanks.
Last edited by farrell2k on Fri. Jan. 24, 2014 1:45 pm, edited 1 time in total.

kstills
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Posts: 639
Joined: Tue. Jan. 18, 2011 6:41 am
Stoker Coal Boiler: WL 110
Stove/Furnace Make: Leisure Line
Location: New Britain, PA

Post Fri. Jan. 24, 2014 1:44 pm

Carbon12 wrote:The KAA2 is only 24 gallons
Dang, that's 12 more than I have, and I have more to heat. Hard to believe he's running out of btuh's to heat 900 sg ft, regardless of the insulation.

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Sting
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Other Heating: OBSO Lennox Pulse "Air Scorcher" burning NG
Location: Lower Fox Valley = Wisconsin

Post Fri. Jan. 24, 2014 1:45 pm

Sounds like a typical over pumping drama -- :D

Do a little searching regarding system balance!
When you turn your boiler on -Does it return the favor?
I have finally lost my mind. Don't bother to return it. It wasn't working properly anyway!

kstills
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Posts: 639
Joined: Tue. Jan. 18, 2011 6:41 am
Stoker Coal Boiler: WL 110
Stove/Furnace Make: Leisure Line
Location: New Britain, PA

Post Fri. Jan. 24, 2014 1:45 pm

farrell2k wrote:
Carbon12 wrote:I was reading it that the circ would turn off below low limit before the demand would be met, the house would cool, circ would come back on at low limit and then the cycle would repeat.
The stove gets up to temperature then the circulator kicks in. The boiler temp drops when the hot water leaves and then the circulator stops until the boiler satisfies the low setting and the cycle starts again. , room temp drops. Can't get above 64 in the room.

I do have the a stat set to 160/180/15 as carbon suggested. I will d see what that does. Thanks.
What kind of radiation do you have?

Regardless, in 900 sq feet, it can't be much.

kstills
Member
Posts: 639
Joined: Tue. Jan. 18, 2011 6:41 am
Stoker Coal Boiler: WL 110
Stove/Furnace Make: Leisure Line
Location: New Britain, PA

Post Fri. Jan. 24, 2014 1:47 pm

Sting wrote:Sounds like a typical over pumping drama -- :D

Do a little searching regarding system balance!
Yeah, but eventually (unless his heat loss exceeded his btuh) he would catch up, right?

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KLook
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Posts: 3631
Joined: Sun. Feb. 17, 2008 1:08 pm
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Other Heating: Gas boiler backup/main
Stove/Furnace Model: VF 3000
Location: Chattanooga, Tenn

Post Fri. Jan. 24, 2014 1:47 pm

At Stings advice, I learned how to make my undersize boiler work pretty well. So what he says X2. ;)

Kevin

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