biomass problems

[EDYS68]

hello i have been reading on this sight all summer and fall, been getting some usefull info on how to hook up my wood boiler to my exsisting gas boiler ive repiped the system a couple of times, still dont have it right. im thinking of piping my gas boiler in series into my wood boiler so when the wood may run out the gas will be turnerd by aquastat and charge the wood boiler tank so the tank is always heated and ready for the load my boilers are next to each other in my garage, my question is also how would i be able to hook up so both boilers run off one pump, the biomass has its own controller. im not very good with coputers dont know how to insert diagrams etc. hope someone could help me, the other problem is with my flue, about 20 ft of pipe and the biomass will not burn hot unless the door is cracked open, even with both fans runing, any diagrams or help will be greatly appreciated. thanks steve

 

[Singed Eyebrows]

Hi EDYS68; Are you using wood that is at 20 percent moisture or less. It sounds like you have single wall pipe that will probably cause some draft loss. Do you have a cap on the flue pipe that promotes draft? You may need to use a motorized draft inducer that goes into the side of the pipe(available from Grainger etc). With dry wood & good draft this should burn well, Randy/ You may need to buy a draft gauge to help troubleshoot this.

 

[EDYS68]

hey singed my flue is single wall 6inch ran up through some double wall 8inch stainless as a chimnney through my roof and attic i was thinking about getting an adapter from 6-8double and useing the double wall as my flue also which may also give me more draft being bigger pipe, right? and yes i am useing 20% and dryer wood thanks

 

[flyingcow]

Just curious what do you have for a wood boiler? and what do you have for a gas boiler? Models etc. Have you burned wood before? if so, what in?

 

[Singed Eyebrows]

hey singed my flue is single wall 6inch ran up through some double wall 8inch stainless as a chimnney through my roof and attic i was thinking about getting an adapter from 6-8double and useing the double wall as my flue also which may also give me more draft being bigger pipe, right? and yes i am useing 20% and dryer wood thanks

Does your boiler specs say 6" chimney? From everything I have read you need to use the recommended pipe size & not larger. No, I would not use 8" flue pipe from the boiler unless the collar on it is 8". The european specs are very picky on chimneys. A good cap will not allow air be to directed down your chimney pipe from a roof etc. & will help with extracting flue gas. Is there some kind of draft control on the Biomass? , Randy

 

[EDYS68]

Flyingcrow the model of my wood boiler is next gen biomass 60 and a larrs mini therm nat gas, and yes i have burned wood in a wood burner inside my house, last two years, one other thing i forgot two mention is that when i close the top door on upper chamber the top chamber fills with excess smoke and idles fire way down, when the door is open( man what a roar!!) and for singed, yes the boiler specs 6inch and there is a sucking fan right up by the exsuast exit ,am i missing something ?

 

[Singed Eyebrows]

Flyingcrow the model of my wood boiler is next gen biomass 60 and a larrs mini therm nat gas, and yes i have burned wood in a wood burner inside my house, last two years, one other thing i forgot two mention is that when i close the top door on upper chamber the top chamber fills with excess smoke and idles fire way down, when the door is open( man what a roar!!) and for singed, yes the boiler specs 6inch and there is a sucking fan right up by the exsuast exit ,am i missing something ?

My Atmos has a balancing valve to control the proportion of smoke generation & burning(primary & secondary). Is there something like this on the Biomass? Are you sure both fans are working properly(impeller did not loosen) & sounds good, not drawing decent air though, Randy

 

[taxidermist]

Flyingcrow the model of my wood boiler is next gen biomass 60 and a larrs mini therm nat gas, and yes i have burned wood in a wood burner inside my house, last two years, one other thing i forgot two mention is that when i close the top door on upper chamber the top chamber fills with excess smoke and idles fire way down, when the door is open( man what a roar!!) and for singed, yes the boiler specs 6inch and there is a sucking fan right up by the exsuast exit ,am i missing something ?

Did you check and see if your primaries are open and not shut all the way? sounds like you are not getting any air into the upper chamber. Can you get it to burn in the secondary chamber?

Rob

 

[heaterman]

"20 feet of pipe".

Is that the total height of your chimney? How far does the horizontal pipe run from the boiler to the chimney?

 

[EDYS68]

well fellow pyros thank you all for all your input i got to reading some more in the manual and went out and found where the primary and secondary adj are they had the secondary to far open and the primarys to far shutso iv got a steady bright yellow flame in the lower chamber now with the door closed. now back to the piping do you think it would be a good idea to pipe my gas boiler through the wood boiler

 

[taxidermist]

well fellow pyros thank you all for all your input i got to reading some more in the manual and went out and found where the primary and secondary adj are they had the secondary to far open and the primarys to far shutso iv got a steady bright yellow flame in the lower chamber now with the door closed. now back to the piping do you think it would be a good idea to pipe my gas boiler through the wood boiler

Glad we could help

Rob

 

[Gooserider]

Glad to hear you have the flue / gasification issue worked out, now for the other problem, how to plumb stuff up...

To start with, as a general rule, it seems to be a very bad idea to use the fossil boiler to heat the storage tank other than possibly to keep it from freezing (most unlikely). It is also generally not the greatest idea to run hot water through an unused boiler, as this just increases your heat losses, without doing much to heat your house...

Remember, the reason we use storage on a wood boiler is because of the near impossibility of turning a wood fire on and off on demand to match the house needs. The storage tank lets the wood boiler be run flat out at a high continuous output, and then go out, while the house draws at a lower and variable demand rate... OTOH, a fossil burner can essentially be turned on and off instantly as demand calls for it, so there is no real advantage to doing storage (with a few exceptions that I'm not going into right now)...

IMHO the best way to plumb stuff, unless there are definite reasons to use a different approach, is to plumb in parallel so that you have your house loads in one loop that has a tee on the supply and return ends. Hook the gas boiler to one side of the tees, and the gasifier and storage to the other side.

Then set up your control strategy so that if the wood boiler is hot, you pull house demand from it and send any surplus heat to the storage tank, if the boiler isn't hot, supply the house demand from the storage, and if both the wood boiler and storage are cold, fire up the fossil boiler as needed to supply the house demand... Some folks will even setup the fossil boiler to be the "last resort" and only let it fire if the temps get down to near freezing or something way under what they would like the wood to keep them at... (called incentive to build a fire... :kiss: )

There are several ways to do the controls so I won't go into that part of it for now, but I'd really do some serious rethinking on the notion of putting the boilers in series, or letting the fossil burner heat the storage tank....

Gooserider