Suck or Blow that is the question
- Thread starter Grover59
- Start date
-
Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.
We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.
We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
- Status
good points ew, In a small , compact boiler all sensors/ dampers are located close to the process trying to be controlled, helping reaction time, ie frolig. I believe in larger commercial boilers, more territory to cover, requiring system loops to be able to be isolated and manipulated independantly, creating more uverlap and redundancy. There are also different degrees of sensitivity amongst o2 sensors used for feedback, Although it seems frolig has taken the long way around, i would love to know the criteria they used for design selection, and i know none of our pockets are deep enough to get the combustion control algorithim. Co2 is a direct correlation to woodgas produced by primary air, and can be calculated from the fuel factor of wood, and the o2%.
Well as I expected I would get some great information from people a hell of a lot smarter them me. The reason I ask is because my Black Bear boiler pushes the air in with one fan, the air takes quite a ride to reach its destination. The idea was to preheat the air before it gets to the primary or secondary chambers. The air takes some 8 turns or more before getting to the end, and there is no way to control the primary air separately from the secondary air, what you have is what you got. Now it works however I believe that there is some room for improvement and so does the guy that designed this boiler.
After the first season using this boiler 2007 I thought that I was not getting enough air flow, even though the boiler seemed to work fine, I just felt it didn't have a big enough super charger on it. So the next season I put a larger blower on it, and boy this did seem to help, now I had some slight control I could block of the intake of the blower if it was too much. I immediately noticed the stack temp go up some to about 410 and I seem to be making more hot water them before. Even though the smaller blower was working it was reducing the output of the boiler, much like the Froling and some others do when they slow the induction fan down based on the load, or tank temps.
Looking at other boilers it appears that those that push air take a more direct route to get to where it needs to be, and they don't seem to care about really preheating the air. So I was playing around with the idea to change this on my boiler, and I also was considering the draft fan because of the obvious reasons like smoke in the house no bypass damper. I am glad I posted this topic, because it has given me more to ponder, I have been looking for a draft blower much like the one on the Froling, centrifugal type can't seem to find one, however at this time a may just work on shortening the air flow path and find a way to control the air flow separately to the primary and secondary chambers. I kind of like the idea of two separate blowers.
Thanks for all of you input and if you have any more ideas please post.
Steve
After the first season using this boiler 2007 I thought that I was not getting enough air flow, even though the boiler seemed to work fine, I just felt it didn't have a big enough super charger on it. So the next season I put a larger blower on it, and boy this did seem to help, now I had some slight control I could block of the intake of the blower if it was too much. I immediately noticed the stack temp go up some to about 410 and I seem to be making more hot water them before. Even though the smaller blower was working it was reducing the output of the boiler, much like the Froling and some others do when they slow the induction fan down based on the load, or tank temps.
Looking at other boilers it appears that those that push air take a more direct route to get to where it needs to be, and they don't seem to care about really preheating the air. So I was playing around with the idea to change this on my boiler, and I also was considering the draft fan because of the obvious reasons like smoke in the house no bypass damper. I am glad I posted this topic, because it has given me more to ponder, I have been looking for a draft blower much like the one on the Froling, centrifugal type can't seem to find one, however at this time a may just work on shortening the air flow path and find a way to control the air flow separately to the primary and secondary chambers. I kind of like the idea of two separate blowers.
Thanks for all of you input and if you have any more ideas please post.
Steve
Nikola Tesla -advocated A/C power. Thomas Edison- advocated D/C power. Both brilliant men, each driving from different political positions. History is our guide to who was correct. Any one heard of the apple computer, history may not always be correct!!
free75degrees
New Member
I was wondering the same thing too. Also, a related question, do induction fans need to be cleaned. I would imagine they would get gunked up over time, whereas a push fan is pretty care free.Floydian said:
ewdudley said:
I don't agree with your thoughts on draft induction in a wood boiler at first glance, but obviously you are a latin speaking combustion engineer of some sort, (I am not, and had too google your last post... please don't do that to me!) %-P so I am open to change those thoughts if you can provide a more thorough explanation of why you think what you think. Why does the secondary air flow take off in an aggravating direction more so on a draft induction wood boiler than a forced draft? Both are metered as a portion of overall air flow through the boiler on units with static settings regardless of forced draft or induction... and both suffer from the effects of the changing volume of woodgas being produced in the firebox. From how you seem to be talking about draft induction, the solo innova boilers with static settings and draft induction shouldnt even work... ?? which is just far from the case. The Froling, which controls fan speed along with the opening of primary and secondary apertures, can deal with this changing volume of woodgas almost instantaneously to peg the residual O2 content in the stack... how is this a bad thing? You also stated: If Frolings are indeed more advanced, and there is nothing beyond marketing hype that says they are, it’s more likely to be despite draft induction than because of it. I would be interested to hear what, if anything, would change your thoughts that "nothing beyond marketing hype" proves they are more advanced? Do you have any first hand experience with the Froling or it's controls to be able to make such a statement? I think this might be a good point to say Non ceteris paribus... :bug:
I don't think it's fair to say that the austrians enjoy complexity for the sake of complexity. Most of the engineering on high end products that come out of Europe seems to be based on longevity, reliabilty, and performance over the long haul. This goes for just about everything from motorcars to wood boilers. The thought process across the pond seems to be geared more in terms of long term benefit, and not necessarily just quick return. Just my opinion. If an efficient boiler with low emissions can be produced at a reasonable cost AND with draft induction for increased ease of use, then the engineering to do such a thing is justified, and not done merely for the sake of being complex. That seems silly to think that... again, just my $.02. If you've lived with both a forced draft boiler and a draft induction boiler in the house, a person can better understand the value of the draft induction.
Respectfully...
Cheers
"in vino veritas" - Doc Holiday, Tombstone :coolsmile:
free73degrees said:
This is why the draft induction models generally always require thermal storage. On a draft induction boiler with thermal storage and decently dry wood, the fins on the fan stay very clean. A light brushing to remove fly ash is all that's required, and can be done when you brush the tubes in the heat exchanger.
Idling a boiler with draft induction would likely cause problems.
cheers
Piker said:
Again just my opinion, any wood boiler runs much better flat out, I decided to go with storage some four years ago, and it is my opinion that every boiler should run with some kind of storage or buffer tank. Just my experience with my boiler and storage tank as stupid as it looks, the storage tank made my life much easier and running the boiler much easier. At this time my boiler is running it will probably run for another two hours and then shut down. For the remainder of tonight and all day tomorrow the house will be heated with whatever is in the stupid looking wooden tank. When I get home tomorrow around 6om I will start another fire, depending on what the tank temp is I will decide how much wood to load.
When I first read that the Froling is designed for storage only, I knew those dudes across the pond knew what they where doing. I take my flue pipe off often, I never see anything except some fly ash, I believe this would not cause a problem with most of these blowers.
Steve
- Status
Similar threads
