Moving heat up stairs

Re: Moving heat up stairs

PostBy: pzou812 On: Sun Dec 20, 2009 2:00 pm

I am wondering the stoker stoves are variable so the heat output is never the same, so wouldn't you think that the anount of cold air return should be variable. When the stove is at idle it would require less cold air and when the stove is calling you would think it would need more cold air return so maybe a fan should be tied in the control circuit of the stove so when it calls for heat the fan kicks on and more cold air is added when its satisfied it would slow the cold air down. Does this make sense to anyone :?:
pzou812
 
Stove/Furnace Make: leisure line
Stove/Furnace Model: pioneer

Re: Moving heat up stairs

PostBy: crocker On: Sun Dec 20, 2009 2:42 pm

No there is a calculated amont of air in the sq ft of your home , the key is to move that certain amount of air in your home in a hourly cycle ,anotherwords returning the proper amount of air to your heating source in a timly matter witch = keeping a even tempeture through out your home , being your stove is automaticly controlled ( thermostaticly conetrolled) it will work more efficently by sensing a more true tempeture of there primary area you are trying to heat (upstasirs) and in turn your stove will heat to higher tempetures as needed from sensing a more uniformed air tempeture throughout the entire home.therefore giving your stove a more efficent operation.
crocker
 

Re: Moving heat up stairs

PostBy: Bratkinson On: Sun Dec 20, 2009 6:59 pm

Although it may seem logical that when turning down the heat level (eg, burn rate) on a stoker, slowing down the convection fan would be a no-brainer.

It's not.

I don't know what the formula may be, but determining how much heat will be radiated through a metal surface (duct), the temperature difference between the two sides of the metal, the composition of the metal (steel, lead, aluminum, etc), and TIME are all factored in. Let's say the metal radiates 100 BTU per hour per square foot between two air surfaces. If a cubic foot of warm air goes by in 1 second, 1/3600 of the 100 BTU (for that hour) will be removed from that air. If the cubic foot takes its time moving by at 2 seconds, then twice the number of fractional BTUs is lost from that cubic foot of air. The next foot of duct, another loss, and so on all the way down the duct. By moving the air quickly through the ductwork, the fewer btus are lost through the metal (and into the basement) from each cubic foot of heated air. Therefore, more BTUs are delivered to the living space.

When I first got my stove, I figured I should be feeling 'toasty' air coming from the heat duct. With only the 265CFM provided by the Dayton blower that came with the stove, what little air came out of the duct next to my living room chair(remember, it was going to 6 other registers, too!) as barely noticable but, it was a little warmer than room temperature. When I slowed down the burn rate and the Dayton fan, there was virtually no air coming out of the heat vent and hence, little or no BTUs, either.

When I bought this house, it had oil heat. I'd never lived in a house with oil forced air heat, and was absolutely amazed at how hot the air coming out of the vents was compared to natural gas that I'd lived with all my life (yes, I'm a big city boy). Not suprisingly, though, was the 'on' cycle of the oil was quite brief compared to what I remembered from gas. As oil went from $.83/gal to $1.24 in three months that winter ('99-'00) and a friend had switched to gas with free-hookup to the street from the gas company, it was a done-deal as soon as I could find a heating-cooling place to do the job. I'd forgotten about how toasty the oil heat was when I fired up the gas that fall. But as oil continued to rise, I was happy.

The lower BTU output from the gas simply took longer to heat the house than oil (5-8 minute cycle with gas, 2-3 minutes with oil). No different than turning down the stoker. BUT...the blower in the oil furnace put out about the same CFMs as the gas furnace! The bottom line is it's all about the CFMs! Whether you put out a lot of BTUs or not so many BTUs, the circular air cycle-rate is an absolute must. I guess these HVAC people must have known that all along!

While it may seem reasonable to slow down the convection air speed for a lower burn, doing so further reduces the number of BTUs delivered to the living area!
Bratkinson
 
Hot Air Coal Stoker Stove: Alaska Channing III
Other Heating: Gas FA
Stove/Furnace Make: Alaska
Stove/Furnace Model: Channing III


Re: Moving heat up stairs

PostBy: crocker On: Sun Dec 20, 2009 8:11 pm

The heat loss you describe , should not be , if a furnace is installed in a conditioned area it would not matter as that space should be at or near the rest of the conditioned house tempeture, if the furnace is installed in a area that is not a conditioned space ,It should be wrapped with duct Insulation no less the 1.5 inches with a reflective backing , the other thing you describe on oil vs natural gas , all furnaces have a low limit and hi limit switch the fan is activated in a sequence of operations all limits are set vertualy the same on fan furnaces in a oil , natural gas or LP gas will not come on till the tempeture of the air is 160 deg f and will continue to operate even after the t/stat is satified until the said furnace return air reaches 140 deg f . I would suspect your new gas furnance was smaller in BTU output and takes a longer cycle to bring your conditioned space up to tempeture , or you have a faulty limit switch , from not replacing your air filter enough starving you furnace for air .somthing is going on there if you feel its not working up to par as your old furnace .
crocker
 

Re: Moving heat up stairs

PostBy: pzou812 On: Sun Dec 27, 2009 6:35 pm

I took some advise from crocker I added a cold air return on the other side of hallway I used a closet and cut a 12"x6"x3' duct in with a 10x10 return grate. And in the basement i cut two 6" duct fans in. It sucks all the cold air from the hallway into the basement by doing this it cut a 10 degree difference down to a 2 to 4 degree difference. It really made it more comfortable to sit downstairs now.
pzou812
 
Stove/Furnace Make: leisure line
Stove/Furnace Model: pioneer

Re: Moving heat up stairs

PostBy: franco b On: Mon Dec 28, 2009 6:50 pm

pzou812 wrote:I am wondering the stoker stoves are variable so the heat output is never the same, so wouldn't you think that the anount of cold air return should be variable. When the stove is at idle it would require less cold air and when the stove is calling you would think it would need more cold air return so maybe a fan should be tied in the control circuit of the stove so when it calls for heat the fan kicks on and more cold air is added when its satisfied it would slow the cold air down. Does this make sense to anyone :?:


Yes it makes sense, but it already does this automatically. As the stove gets hotter the volume of hot air increases causing a corresponding increase in the cold air return.
franco b
 
Hand Fed Coal Stove: V ermont Castings 2310, Franco Belge 262
Baseburners & Antiques: Glenwood Modern Oak 114
Coal Size/Type: nut and pea