Problems with kaa-2 temps.

Re: Problems with kaa-2 temps.

PostBy: Pacowy On: Wed Jan 29, 2014 10:24 am

I have a couple of concerns with this whole discussion, and the ways it seems to try to put a happy face on the problems associated with undersized boilers. First, the heat going out from the boiler needs to at least match the heat transfer that is performed by the installed radiation (i.e., the heating load), not any "heat loss" estimated through other means. The radiators don't care what a computer program computes as a heat loss; they will transfer btu's at well-defined rates until the controls tell them they can stop. If there has been a setback, an open window or door, a boo-boo in the heat loss program, a spouse pushing up the thermostat because they feel cold, etc., installed radiation will transfer btu's up to its own capacity without regard to any heat loss computation. The system will slide backwards if it can't put btu's into the radiation as fast as the radiation puts them into the living space.

On a related note, I think all of the people proposing to address the low output problem by changing the controls so the circulator is not interrupted by the low limit should relax. I'm not a hydronics guy, but I'm pretty sure that any system in which playing with the circulator at the low limit would make a measurable difference in the ability of the boiler to carry the load has already been confiscated by the Conservation of Energy Police, because AFAIK it would violate the first law of thermodynamics. As long as the stoker is running (and I can't imagine why it wouldn't be when the system goes under the low limit) the btu's are going into the boiler water; if the system won't get off the low limit, the problem is that the radiators are giving up the btu's faster than the boiler can make them. To be clear, I'm not saying it would be a bad idea to have the circulator run independent of the low limit (e.g., for the reason whistlenut has raised). I'm only saying that it appears to be impossible for that to form any meaningful part of a solution to the underlying problem of the boiler being too small.

Mike
Pacowy
 
Stoker Coal Boiler: H.B. Smith 350 Mills boiler/EFM 85R stoker
Coal Size/Type: Buckwheat/anthracite

Re: Problems with kaa-2 temps.

PostBy: Sting On: Wed Jan 29, 2014 10:52 am

Pacowy wrote:The system will slide backwards if it can't put btu's into the radiation as fast as the radiation puts them into the living space.
Mike


and if the circulator is not running due to the diafunctional Triple Aquastat in control -- the above has EVERYTHING to due with boiler size -- or as you cannot get off your soap box enough -- boiler undersize
Sting
 
Other Heating: BurnHAM=NG-gas

Re: Problems with kaa-2 temps.

PostBy: kstills On: Wed Jan 29, 2014 10:56 am

Pacowy wrote:I have a couple of concerns with this whole discussion, and the ways it seems to try to put a happy face on the problems associated with undersized boilers. First, the heat going out from the boiler needs to at least match the heat transfer that is performed by the installed radiation (i.e., the heating load), not any "heat loss" estimated through other means. The radiators don't care what a computer program computes as a heat loss; they will transfer btu's at well-defined rates until the controls tell them they can stop. If there has been a setback, an open window or door, a boo-boo in the heat loss program, a spouse pushing up the thermostat because they feel cold, etc., installed radiation will transfer btu's up to its own capacity without regard to any heat loss computation. The system will slide backwards if it can't put btu's into the radiation as fast as the radiation puts them into the living space.

On a related note, I think all of the people proposing to address the low output problem by changing the controls so the circulator is not interrupted by the low limit should relax. I'm not a hydronics guy, but I'm pretty sure that any system in which playing with the circulator at the low limit would make a measurable difference in the ability of the boiler to carry the load has already been confiscated by the Conservation of Energy Police, because AFAIK it would violate the first law of thermodynamics. As long as the stoker is running (and I can't imagine why it wouldn't be when the system goes under the low limit) the btu's are going into the boiler water; if the system won't get off the low limit, the problem is that the radiators are giving up the btu's faster than the boiler can make them. To be clear, I'm not saying it would be a bad idea to have the circulator run independent of the low limit (e.g., for the reason whistlenut has raised). I'm only saying that it appears to be impossible for that to form any meaningful part of a solution to the underlying problem of the boiler being too small.

Mike



I'm in agreement with this.

At some point, there won't be any 'idle time' involved. You'll be making heat as fast as you can make it, and the system is going to equilibrate to the setting on the boiler, either LL orHL.

Whether or not that raises, lowers or holds the temperature steady in the dwelling becomes a matter of what the heat loss is, vs the output of the radiation.
kstills
 
Stoker Coal Boiler: WL 110
Stove/Furnace Make: Leisure Line

Visit Lehigh Anthracite

Re: Problems with kaa-2 temps.

PostBy: windyhill4.2 On: Wed Jan 29, 2014 11:12 am

Years ago i heated a totally uninsulated block wall garage with no ceiling insulation, 1200 sq. ft.,with an old hot air mobile home unit 80k -- hot air ! he has hot water & should be able to easily heat 900 sq.ft. with that unit ! Set the water temp up,set controls to run unit more consistently,stop the yo-yo effect that is not allowing system to make heat.Install those pins as oliver power said,get the circulator running & start heating that little house up !! Some of you guys need to step outside & clear the fog from your brain,if his boiler is under sized it would be firing 25 hrs/day -nonstop,he says boiler gets water temp up & cycles off,get the whole system working together & problem will be solved, KEEP IT SENSIBLE SIMPLE,good grief !!!
windyhill4.2
 
Hand Fed Coal Stove: Crane 404 with variable blower
Other Heating: Oaktree OWB 600K

Re: Problems with kaa-2 temps.

PostBy: KLook On: Wed Jan 29, 2014 12:19 pm

Pacowy wrote:I have a couple of concerns with this whole discussion, and the ways it seems to try to put a happy face on the problems associated with undersized boilers. First, the heat going out from the boiler needs to at least match the heat transfer that is performed by the installed radiation (i.e., the heating load), not any "heat loss" estimated through other means. The radiators don't care what a computer program computes as a heat loss; they will transfer btu's at well-defined rates until the controls tell them they can stop. If there has been a setback, an open window or door, a boo-boo in the heat loss program, a spouse pushing up the thermostat because they feel cold, etc., installed radiation will transfer btu's up to its own capacity without regard to any heat loss computation. The system will slide backwards if it can't put btu's into the radiation as fast as the radiation puts them into the living space.

On a related note, I think all of the people proposing to address the low output problem by changing the controls so the circulator is not interrupted by the low limit should relax. I'm not a hydronics guy, but I'm pretty sure that any system in which playing with the circulator at the low limit would make a measurable difference in the ability of the boiler to carry the load has already been confiscated by the Conservation of Energy Police, because AFAIK it would violate the first law of thermodynamics. As long as the stoker is running (and I can't imagine why it wouldn't be when the system goes under the low limit) the btu's are going into the boiler water; if the system won't get off the low limit, the problem is that the radiators are giving up the btu's faster than the boiler can make them. To be clear, I'm not saying it would be a bad idea to have the circulator run independent of the low limit (e.g., for the reason whistlenut has raised). I'm only saying that it appears to be impossible for that to form any meaningful part of a solution to the underlying problem of the boiler being too small.

Mike




I'm in agreement with this.

At some point, there won't be any 'idle time' involved. You'll be making heat as fast as you can make it, and the system is going to equilibrate to the setting on the boiler, either LL orHL.

Whether or not that raises, lowers or holds the temperature steady in the dwelling becomes a matter of what the heat loss is, vs the output of the radiation


And I am in disagreement. For many reasons but I will be short. Oliver and I are the only 2 that have the same situation as this gentleman. We have made our little boilers that could work. As Oliver said, I would think he would try what those with the same experience have found to work FIRST.
If it doesn't work then all you experts can chime in and save the day. I am amazed at the sniping by people when the guy needs some help. It adds to his confusion.
Kstills, your premise that the system will catch up is just wrong. I said it way back but you ignored it. My boiler would drop to 140 or less and then it would just churn for days until the load was decreased. You are not thinking about this because you said you could run 160 water, and 160 will not work for an undersized boiler. It needs to start out at about 200, or better and drop to 160 maybe. It needs to have a head start, put out all the heat it can store, and get fired up just as soon as a zone calls. Even better with Olivers increased pins so long as it doesnt go over the high limit and dump.


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: Pacowy On: Wed Jan 29, 2014 12:31 pm

windyhill4.2 wrote:Years ago i heated a totally uninsulated block wall garage with no ceiling insulation, 1200 sq. ft.,with an old hot air mobile home unit 80k -- hot air ! he has hot water & should be able to easily heat 900 sq.ft. with that unit ! Set the water temp up,set controls to run unit more consistently,stop the yo-yo effect that is not allowing system to make heat.Install those pins as oliver power said,get the circulator running & start heating that little house up !! Some of you guys need to step outside & clear the fog from your brain,if his boiler is under sized it would be firing 25 hrs/day -nonstop,he says boiler gets water temp up & cycles off,get the whole system working together & problem will be solved, KEEP IT SENSIBLE SIMPLE,good grief !!!


I think it was oliver power, not the (other) OP, who said their stoker shut off/went into idle mode below the low limit. I think everybody agrees the stoker should run when the system goes below the low limit.

The OP described the circulator shutting down while the stoker worked to get the system back up to the low limit. For the reasons I outlined above, a sustained problem of this type will not "be solved" by changing the idle settings of the stoker or the circulator controls. If you want to keep it sensible and simple, remember that the boiler is storing any btu's imparted to the water when it is running below the low limit. Whether they are released continuously or in batches, the overall boiler output and its relation to the radiation to which it is connected are unchanged.

Mike
Pacowy
 
Stoker Coal Boiler: H.B. Smith 350 Mills boiler/EFM 85R stoker
Coal Size/Type: Buckwheat/anthracite

Re: Problems with kaa-2 temps.

PostBy: KLook On: Wed Jan 29, 2014 12:35 pm

If you want to keep it sensible and simple, remember that the boiler is storing any btu's imparted to the water when it is running below the low limit. Whether they are released continuously or in batches, the overall boiler output and its relation to the radiation to which it is connected are unchanged.


Wrong, the radiation will not put out heat with low water temps. Just the way it works. It is designed for 180 water and that is what is required to get the rated Btu's/ft. CIrculating warm water will keep the pipes from freezing and the house, but he will be cold.

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: windyhill4.2 On: Wed Jan 29, 2014 12:38 pm

Oliver & Klook have a working understanding,try their advice & as klook stated ,when that is not sufficient then follow the experts advice :)
windyhill4.2
 
Hand Fed Coal Stove: Crane 404 with variable blower
Other Heating: Oaktree OWB 600K

Re: Problems with kaa-2 temps.

PostBy: kstills On: Wed Jan 29, 2014 12:42 pm

Ok, someone check my math.

You have a boiler with a capacity of 24 gallons, sitting at 180 degrees, yielding ~36k btus of stored heat.

You have ~100 feet of three quarters inch radiation, with another 100 feet of piping in the basement, capacity of 8 gallons of water sitting at 86 degrees (difference in room temp and basement supply temp).

You're pumping out of the boiler at 4gallons per minute, delivering ~6000btus per minute (180X4X8.334=6000).

You have radiation capacity of 1016btus per minute at 180 f (610btuh/ftX100ft)/60min=1016btum.

You are returning to the boiler 4gpm of 5000btu water.

4 gallons of water at 5000btu = 150f water.

The delta in the boiler in the first minute will be -3deg, taking the boiler from 180 to 177f.

At 60000btuh boiler output, you're adding 1000btu/m to the boiler, which effectively replaces all the loss in radiation.

How would it be possible to overwhelm the boiler given that setup?
kstills
 
Stoker Coal Boiler: WL 110
Stove/Furnace Make: Leisure Line

Re: Problems with kaa-2 temps.

PostBy: kstills On: Wed Jan 29, 2014 12:53 pm

KLook wrote:


And I am in disagreement. For many reasons but I will be short. Oliver and I are the only 2 that have the same situation as this gentleman. We have made our little boilers that could work. As Oliver said, I would think he would try what those with the same experience have found to work FIRST.
If it doesn't work then all you experts can chime in and save the day. I am amazed at the sniping by people when the guy needs some help. It adds to his confusion.
Kstills, your premise that the system will catch up is just wrong. I said it way back but you ignored it. My boiler would drop to 140 or less and then it would just churn for days until the load was decreased. You are not thinking about this because you said you could run 160 water, and 160 will not work for an undersized boiler. It needs to start out at about 200, or better and drop to 160 maybe. It needs to have a head start, put out all the heat it can store, and get fired up just as soon as a zone calls. Even better with Olivers increased pins so long as it doesnt go over the high limit and dump.


Kevin


You misunderstand.

There isn't any sniping going on, there's an honest disagreement on what the problem is, brought about by a lack of information about what exactly the OP is seeing in his system.

We still don't know if his boiler is returning water and falling below the low limit on the aquastat. By my calculations above, I find it hard to believe that would even be possible, however I'm doing calculations on heat loss and heat transfer for the first time so there may be some mistakes in either my math or the assumptions I'm making.

Also, I have perhaps the worst of all possible hydronic setups, I'm trying to feed 75 gallons system capacity with a 12 gallon heated supply. So while I don't have the KA2, I have plenty of experience watching my boiler try to catch up as it's being flooded with cold water.

It's because of my experience watching MY boiler operate under those conditions that I'm confused by your and Olivers responses. MY boiler is overwhelmed in mild temperature conditions, yet over time it recovers and supplys the heat I need to the house. In temperatures close to design, it raises the entire system temperature up to the low limit of the boiler, and that's what circulates until the call for heat is satisfied.

And it does it with a much smaller capacity than either yours, Olivers or Farrel2ks.
kstills
 
Stoker Coal Boiler: WL 110
Stove/Furnace Make: Leisure Line

Re: Problems with kaa-2 temps.

PostBy: KLook On: Wed Jan 29, 2014 1:02 pm

Don't care about your math. I have a boiler with a 50 gal capacity. When certain zones called and it was COLD out, with my zones allowed to flow water at full speed, my boiler would lose temp, and because the sensor to get it running was on the TOP, it would be stone cold and recirculating cold water before the damn thing even fired up! Then you are starting from scratch trying to heat up water that is whipping through the boiler faster then it can be heated. With your thinking, that boiler is supposed to heat up water that is changing in the vessel every 2 minutes at a min. Probably much faster then that in reality. It cannot do it with the load being to great and the coal bed being so small.

Kevin

The boiler you have is more efficient in the heat exchange area. and 12 gal can be heated quicker then 24 or 50. It is the exchange rate of the water through the vessel and the volume of water that is making it not work. It cannot put out enough btu's to heat up 24 gals of cold water. And mine could not heat up 50 gals. I slowed it down and kept the water in the boiler longer and it would catch up. YOU do not have a boiler like ours.
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: KLook On: Wed Jan 29, 2014 1:10 pm

Your boiler works on the same principle as the on demand water heaters. You can spit cold water through them at full speed and they heat it up. But it is pushed through small ports that get the water in contact with as much exchanger surface is possible and I guess they create condensation and have short lives if the water is hard.
Ours work on having large water storage and matching the flow(btu's/gal = flow/min) @ X temp. If you are feeding radiant heat, then you can circulate all the 140 water you want. If you are feeding baseboard, toe kicks, and cast iron like I am, you better have a min. of 160 and that is after some hotter stuff has already gone out and put out some heat where demanded. I have a radiant slab also but it is an injection system and always has enough heat in the water to work.

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: KLook On: Wed Jan 29, 2014 1:14 pm

I think there are multiple issues with the OP's system. He is going to need a visit from one of you guys that have some experience. No matter if you agree with us or not, improvements can be made just be confirming flow, air blocks, and wiring issues. Hope some one can get over there and advise him. And maybe save him a few bucks in the process. Dang it is cold! 7 here in Chattanooga this morning and everything is shut down.

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: Pacowy On: Wed Jan 29, 2014 1:17 pm

Sting wrote:
Pacowy wrote:The system will slide backwards if it can't put btu's into the radiation as fast as the radiation puts them into the living space.
Mike


and if the circulator is not running due to the diafunctional Triple Aquastat in control -- the above has EVERYTHING to due with boiler size -- or as you cannot get off your soap box enough -- boiler undersize


I would agree that the stoker not running below the low limit sounds dysfunctional, but I'm not sure why you seem to be defining it as dysfunctional for the circulator to stop when the boiler cools down too much. Maintaining a minimal temperature of boiler water is needed to maintain functionality of any DHW coil or indirect that the boiler may power. At the same time, circulating cool boiler water can't and doesn't impart many btu's to the living space. Hard to see circulator operation below the low limit as part of either the problem or the solution.

I try to make sure my "soap box" is based on the relevant science and engineering considerations, and consistent with available evidence. I don't have any plans to get off it any time in the foreseeable future. If you think I'm missing something in the science, engineering and/or evidence, please fill in the blanks so that I and others can learn.

Mike
Pacowy
 
Stoker Coal Boiler: H.B. Smith 350 Mills boiler/EFM 85R stoker
Coal Size/Type: Buckwheat/anthracite

Re: Problems with kaa-2 temps.

PostBy: Pacowy On: Wed Jan 29, 2014 1:27 pm

KLook wrote:
If you want to keep it sensible and simple, remember that the boiler is storing any btu's imparted to the water when it is running below the low limit. Whether they are released continuously or in batches, the overall boiler output and its relation to the radiation to which it is connected are unchanged.


Wrong, the radiation will not put out heat with low water temps. Just the way it works. It is designed for 180 water and that is what is required to get the rated Btu's/ft. CIrculating warm water will keep the pipes from freezing and the house, but he will be cold.

Kevin


Not sure why you say "wrong". My point is that the guy is going to be cold either way - i.e., whether circulating warm water continuously or warmer water in batches. I agree on the 180 deg design factor - it's why circulating the warm water can't do much.

Mike
Pacowy
 
Stoker Coal Boiler: H.B. Smith 350 Mills boiler/EFM 85R stoker
Coal Size/Type: Buckwheat/anthracite

Visit Lehigh Anthracite

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