Problems With KAA-2 Temps.

Post Reply
 
farrell2k
Member
Posts: 217
Joined: Sun. Nov. 11, 2012 4:38 pm
Location: Perkasie Pa.
Stoker Coal Boiler: Kaa2

Post by farrell2k » 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.
20140124_110741.jpg
.JPG | 154.1KB | 20140124_110741.jpg
20140124_110755.jpg
.JPG | 122.7KB | 20140124_110755.jpg
20140124_110841.jpg
.JPG | 114.7KB | 20140124_110841.jpg
20140124_110948.jpg
.JPG | 125.5KB | 20140124_110948.jpg


 
User avatar
Carbon12
Member
Posts: 2226
Joined: Tue. Oct. 11, 2011 6:53 pm
Location: Harrisburg, PA
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace

Post by Carbon12 » Fri. Jan. 24, 2014 1:03 pm

Try a diff of 15

 
kstills
Member
Posts: 637
Joined: Tue. Jan. 18, 2011 6:41 am
Location: New Britain, PA
Stoker Coal Boiler: WL 110

Post by kstills » Fri. Jan. 24, 2014 1:06 pm

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

 
User avatar
Carbon12
Member
Posts: 2226
Joined: Tue. Oct. 11, 2011 6:53 pm
Location: Harrisburg, PA
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace

Post by Carbon12 » 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

 
kstills
Member
Posts: 637
Joined: Tue. Jan. 18, 2011 6:41 am
Location: New Britain, PA
Stoker Coal Boiler: WL 110

Post by kstills » 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.

 
User avatar
Carbon12
Member
Posts: 2226
Joined: Tue. Oct. 11, 2011 6:53 pm
Location: Harrisburg, PA
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace

Post by Carbon12 » 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.

 
kstills
Member
Posts: 637
Joined: Tue. Jan. 18, 2011 6:41 am
Location: New Britain, PA
Stoker Coal Boiler: WL 110

Post by kstills » 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'...


 
User avatar
Carbon12
Member
Posts: 2226
Joined: Tue. Oct. 11, 2011 6:53 pm
Location: Harrisburg, PA
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace

Post by Carbon12 » Fri. Jan. 24, 2014 1:36 pm

The KAA2 is only 24 gallons

 
KLook
Member
Posts: 5791
Joined: Sun. Feb. 17, 2008 1:08 pm
Location: Harrison, Tenn
Other Heating: Wishing it was cold enough for coal here....not really

Post by KLook » 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
Member
Posts: 217
Joined: Sun. Nov. 11, 2012 4:38 pm
Location: Perkasie Pa.
Stoker Coal Boiler: Kaa2

Post by farrell2k » 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
Member
Posts: 637
Joined: Tue. Jan. 18, 2011 6:41 am
Location: New Britain, PA
Stoker Coal Boiler: WL 110

Post by kstills » 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.

 
User avatar
Sting
Member
Posts: 2983
Joined: Mon. Feb. 25, 2008 4:24 pm
Location: Lower Fox Valley = Wisconsin
Other Heating: OBSO Lennox Pulse "Air Scorcher" burning NG

Post by Sting » Fri. Jan. 24, 2014 1:45 pm

Sounds like a typical over pumping drama -- :D

Do a little searching regarding system balance!

 
kstills
Member
Posts: 637
Joined: Tue. Jan. 18, 2011 6:41 am
Location: New Britain, PA
Stoker Coal Boiler: WL 110

Post by kstills » 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: 637
Joined: Tue. Jan. 18, 2011 6:41 am
Location: New Britain, PA
Stoker Coal Boiler: WL 110

Post by kstills » 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?

 
KLook
Member
Posts: 5791
Joined: Sun. Feb. 17, 2008 1:08 pm
Location: Harrison, Tenn
Other Heating: Wishing it was cold enough for coal here....not really

Post by KLook » 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


Post Reply

Return to “Stoker Coal Boilers Using Anthracite (Hydronic & Steam)”