Outdoor Wood Furnace Info

Outdoor Furnaces - Manufacturers with NON EPA-Certified Models Only => Aqua-Therm => Topic started by: ironwood on September 20, 2010, 11:09:55 AM

Title: slow the fan down!
Post by: ironwood on September 20, 2010, 11:09:55 AM
Has anyone tried slowing the fan down on an AquaTherm or better yet, relied on the flapper for the fresh air when aquastat calls for it?
Title: Re: slow the fan down!
Post by: vpd66 on September 28, 2010, 10:35:16 AM
I have a 145 and often wondered that myself. It seems at times  (when wood load is half burnt and less) that you wouldn't need the blower. I had an idea last year that if a guy put a temp sensor in the flue stack and used one of those cheap PID temp controllers to control the blower motor. If stack temps are above 400 degrees, cut the blower and just let the flap open. Or when the stack temp is below 400 degrees let the blower open with the flap open (like it normally runs). Of course all this would be wired in after the aquastat, so the aquastat still has control when the boiler calls for air. I believe that this would cut wood consumption. There is quite a few times when I open the boiler door and the fire is like a blow torch burning very hot. I believe at these conditions the blower could be cut and just let air in through the flap.  Does this sound like what your thinking?
Title: Re: slow the fan down!
Post by: MattyNH on September 28, 2010, 02:14:16 PM
Really not sure how much you would save wood if you shut fan off..I would think the fire would burn longer to bring the temp up to where you have temp set....At times ive opened my door and theres no fire all..It would take awhile to get that fire going again and burn longer if you had natural draft..
Title: Re: slow the fan down!
Post by: MattyNH on September 28, 2010, 03:51:24 PM
Eco-one running a fasco 1/30 hp , 135 cfm... outlet is square..Its stock
Title: Re: slow the fan down!
Post by: vpd66 on September 29, 2010, 08:21:56 AM
Matt, I don't think you got what I was talking about. My idea was to cut the fan and just have the flap open when stack temps (not water temps) get above 400 degrees. In your case when you see no fire the stack temps would be low and that would allow the flap to open and the fan to run. When the fire got up to temp then it would cut the blower and just run with the flap open. Make sense??? Like I said, there are times when I have a great bed of coals and I don't think I need the blower operating. I think at these times it would run good with just the flap open.
Title: Re: slow the fan down!
Post by: MattyNH on September 29, 2010, 01:21:03 PM
 I see what your sayig..For me I couldnt do that..My stack is 20feet up..I  would think Id need the hotter temps to keep the stack from plugging up..That would be one concern for me..
Title: Re: slow the fan down!
Post by: atvalaska on December 05, 2014, 02:11:17 PM
I talked to a guy in MI , they have installed a system where the fans come on /the fire starts, then once the fire is really going >it cuts the fans and then holds the flap up for natural draft, then shuts off at AQ temp ......says it keeps from blowing all the heat out the chimney........
Title: Re: slow the fan down!
Post by: vpd66 on December 11, 2014, 07:43:56 AM
I talked to a guy in MI , they have installed a system where the fans come on /the fire starts, then once the fire is really going >it cuts the fans and then holds the flap up for natural draft, then shuts off at AQ temp ......says it keeps from blowing all the heat out the chimney........

Cool! Any contact info for this guy that is doing the mod??
Title: Re: slow the fan down!
Post by: atvalaska on December 11, 2014, 09:43:04 AM
I'm a longs ways from them guys and did not want to bother them , they  did not say how ,but the idea is a good one ...so I'm going to work it out myself   they did tell me to put a snap disk on the supply pipe and have it shut off the blowers when > it is out of wood/ u were late in filling >so as  to not keep blowing cold air on a non extant fire  -thus cooling the water/boiler even more...
Title: Re: slow the fan down!
Post by: vpd66 on December 11, 2014, 10:18:30 AM
I'm a longs ways from them guys and did not want to bother them , they  did not say how ,but the idea is a good one ...so I'm going to work it out myself   they did tell me to put a snap disk on the supply pipe and have it shut off the blowers when > it is out of wood/ u were late in filling >so as  to not keep blowing cold air on a non extant fire  -thus cooling the water/boiler even more...

I guess I could figure it out myself,but I've been waiting for my Aqua-Therm to die so I could replace it with something more efficient. So i don't care to spend too much time or money on this boiler. By the way, did you know Aqua Therm had a Eco one upgrade that was claimed to up efficientcy before they went under. It replaced the baffle and added another blower to the door that looked like they were trying to burn the wood gas above the fire. They wanted like $500.00 for this upgrade. To rich for my blood.
Title: Re: slow the fan down!
Post by: fryedaddy on December 11, 2014, 02:35:17 PM
Forced air is what makes your stove efficient.

Burning with a natural draft would be a downgrade for your stove.
Title: Re: slow the fan down!
Post by: atvalaska on December 11, 2014, 03:17:05 PM
I'm a longs ways from them guys and did not want to bother them , they  did not say how ,but the idea is a good one ...so I'm going to work it out myself   they did tell me to put a snap disk on the supply pipe and have it shut off the blowers when > it is out of wood/ u were late in filling >so as  to not keep blowing cold air on a non extant fire  -thus cooling the water/boiler even more...

I guess I could figure it out myself,but I've been waiting for my Aqua-Therm to die so I could replace it with something more efficient. So i don't care to spend too much time or money on this boiler. By the way, did you know Aqua Therm had a Eco one upgrade that was claimed to up efficientcy before they went under. It replaced the baffle and added another blower to the door that looked like they were trying to burn the wood gas above the fire. They wanted like $500.00 for this upgrade. To rich for my blood.
  that's what I have........ 
Title: Re: slow the fan down!
Post by: atvalaska on December 11, 2014, 03:22:29 PM
Forced air is what makes your stove efficient.

Burning with a natural draft would be a downgrade for your stove.
   that's what... "they say" ....the idea is to not press the hot air out the stove with 270 cfm's  of fan once the fire is burning   ...which  in turn makes the  heat stay inside longer.  I'm still learning ..but than again I have never bought something that "a man " built ...that I could not improve on ..that goes for cars, trucks ,4 wheelers snowgoes and boats !  :) .....
Title: Re: slow the fan down!
Post by: slimjim on December 12, 2014, 03:07:10 AM
OK guys, follow me on this one, I'm not sure the stack temp is the right place to do this as most conventional boiler stacks are pretty dirty and true temp readings might be hard to monitor but if you used the water temp then what you are proposing is easy to do on any conventional, I think it's a great idea and may try it at home on my old Wood Booger.
  For those of you who would like to try it, this is what I would try, Place the Honeywell strap on Aqua Stat that I use (6006C-1018) on your supply line, use the R+W terminals to interrupt just the blower power wire at about 5 degrees below your set point or target temp, lets say target temp or shutoff is 185 degrees with 10 degree differential, you set the strap on at say 180, blower comes on at 175 and runs to 180 then the blower shuts off but damper stays open until target temp is reached at 185 or if there is enough load and the temp falls again to 179 then the blower comes back on.
  I think it's a GREAT IDEA, Thanks Ironwood
Title: Re: slow the fan down!
Post by: hondaracer2oo4 on December 12, 2014, 06:37:35 AM
I like the idea! Slim, why not use a Ranco or Johnson controller instead? More easily programmable and it is cheaper then a honeywell mechanical. I have a honeywell 6006C-1018 that I use to shut off the blower if my temps drop below 160 to save the coals like you suggested but they are a little pricey AND I dont have anywhere to strap it to that is copper or metal so I had to strap mine to the Pex supply line and wrap it really good with insulation but it still registers 10 degrees below the actual temp because of the pex being a bad conductor. I would think that you could zip tie the Ranco sensor to the pex and insulate it and it would be just as accurate.
Title: Re: slow the fan down!
Post by: atvalaska on December 12, 2014, 09:20:12 AM
ironwood don't care :(   I was doing a net search looking for any one else who gave this idea a shot, and didn't check the date  ! >

""slow the fan down! ""

« on: September 20,**** 2010***, 11:09:55 AM »
Title: Re: slow the fan down!
Post by: atvalaska on December 12, 2014, 09:33:58 AM
what I do know > if u have a model with 2 fans , they  need the same mods (each  fan) to make them work ,I disabled  one of my fans as I felt the stove would work with only one fan ...it does ...then once the fire gets started = it blows the smoke out the "disabled fans " every little hole! In order to make that work ,I would have to remove fan a block off hole with a plate. .......... SLIM ... there is another way  to do it with out a AQsta...was thinking a R.I.B.  timer/delay  it would work like so = your regular sta would shut off the fan /shutter assy ...but the shutter would go thru the RIB and not cut the power to drop the it  "flap/shutter" till it timed out.....thinking out loud here.....
Title: Re: slow the fan down!
Post by: fryedaddy on December 18, 2014, 07:52:32 AM
My stove has a blower and (2) dampers.

The dampers were installed as a backup if power were to go out.

I've tried running it with the blower, blower to start the fires and dampers only (after a bed of coals has been established).

I was under the same impression the the slower the fire the more time for BTUs to transfer but I keep proving myself wrong.

Burning as hot a fire as possible to more efficient and transfers heat better. Burning a slower fire (i Believe) adds creasote and
ash to the transfer surfaces and restricts transfer.

Just my beliefs, my situation may be a little different as well because I batch burn and have a large water volume.
Title: Re: slow the fan down!
Post by: vpd66 on December 18, 2014, 08:02:39 AM
My stove has a blower and (2) dampers.

The dampers were installed as a backup if power were to go out.

I've tried running it with the blower, blower to start the fires and dampers only (after a bed of coals has been established).

I was under the same impression the the slower the fire the more time for BTUs to transfer but I keep proving myself wrong.

Burning as hot a fire as possible to more efficient and transfers heat better. Burning a slower fire (i Believe) adds creasote and
ash to the transfer surfaces and restricts transfer.

Just my beliefs, my situation may be a little different as well because I batch burn and have a large water volume.

Thats the problem with these AquaTherms. Too much heat goes up the stack. They are just a barrel in a barrel style (fire box with a water jacket around them) and they only hold 45 gallons of water. Heat transfer is fast and alot is wasted up the stack. We are trying to just use the blower to restart the fire, then shut it off and just let the fire burn with the damper open. With the damper open and blower going it is like a blow torch in mine after the fire is going good.
Title: Re: slow the fan down!
Post by: Propster on March 14, 2015, 10:41:42 AM
I'm late to this discussion but would it be possible to reduce the power/speed/rpms of the motor running the draft fan? I.e. smaller motor?