Low Draft During Spring Days

 
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gerry_g
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Post by gerry_g » Wed. Apr. 15, 2015 7:09 pm

I've run into a problem with my Pioneer and variable spring weather. Where I live (MA) I just had a 75F day and a 28F night.

I had the coal trol set to 76 but the stove went down to the minimum feed rate. Late in the afternoon on the 75 degree day, my CO alarm went off. There are several issues that may have triggered this.

- When so warm in the day, my stainless 6 inch chimney doesn't create an acceptable draft if the stove is running at the preset min feed rate.

- Shutting down the stove and lighting it on nearly a daily basis is a pain. I can still have very cold weather and mild days.

- At very low draft, fly ash really accumulates in my 2 foot horizontal section of stove pipe + through the wall chimney section, further reducing the draft.

Now, what is a decent solution?

- Note, CO alarm requirements have changed dramatically in the past 3-5 years. Due to false alarms, new CO alarms now don't trigger until CO exceeds 70 ppm for 1-4 hour. In ~2010 they triggered at 30+ PPM. So maybe I had a false alarm. CO alarms only last 5-10 years anyway. I just ordered a "new spec" digital alarm with a 10 year lithium battery. The new alarms start beeping after their specified lifetime expires.

- Unfortunately auto ignition has not worked out with coal combustion temperatures.

- Perhaps I could set the min feed rate higher and open windows ;) Heck, in the 1950's we did that with a central coal furnace, manual air feed

- Many oil and gas furnaces now have a draft inducer. It is basically just a small fan in the flue outlet that maintains a minimum draft. Convection maintains the main draft when operating at medium to high. (Some modern furnaces have variable output)

Since electronic ignition doesn't work well, any thoughts?


 
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Flyer5
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Post by Flyer5 » Wed. Apr. 15, 2015 7:15 pm

You can try a higher min setting. Make sure your pipes are clean and not reduced as well. If the pipes are clear. A better option over raising the min is to block of the inlet of the combustion fan. This can be done with duct tape. Try starting at 1/2. A good indicator of low draft or high over fire pressure is sweat on the hopper lid. There should never be moisture above the coal line in the hopper.

 
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Post by WNY » Wed. Apr. 15, 2015 7:43 pm

i usually raise my min to 8 or 10 to get a little higher idle temps.

You can clean the pipes good, and maybe block off your Baro Damper to draw a little more from the stove.

But, YES, keep an eye on the CO.

 
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Post by davidmcbeth3 » Wed. Apr. 15, 2015 8:11 pm

I would guess the best course of action is to burn a little bit hotter than you would like to get the draft going and use your window-stats to control the temperature desired.

I'm lucky I guess, I can idle my stove down to a crawl w/o issue.

 
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Post by 2001Sierra » Wed. Apr. 15, 2015 10:53 pm

Wouldn't blocking the baro or covering it help to increase over fire draft? Just a suggestion, anyone have an opinion?

 
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Post by Lightning » Thu. Apr. 16, 2015 5:36 am

Also, crack a window open in the stove room. This will equalize any negative pressure (will bring the neutral pressure plane to that level) that could be occurring due to stack effect in the house.

 
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Post by blrman07 » Thu. Apr. 16, 2015 6:59 am

Can't move my neutral plane. It's too heavy. :lol:

Burn hotter and operate the window stats during the day time.


 
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Post by Flyer5 » Thu. Apr. 16, 2015 10:40 am

2001Sierra wrote:Wouldn't blocking the baro or covering it help to increase over fire draft? Just a suggestion, anyone have an opinion?
Do not block the baro off on a stoker.

 
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Post by gerry_g » Thu. Apr. 16, 2015 11:46 am

Lightning wrote:Also, crack a window open in the stove room. This will equalize any negative pressure (will bring the neutral pressure plane to that level) that could be occurring due to stack effect in the house.
I should have mentioned I have no windows in the room, it is a finished family room in the basement of my ranch with no windows.

A power vent is useless in my situation because to maintain fire clearance from the room's ceiling, my chimney outlet is too close to the ground. Not that I really care for power vents, maintenance, lifetime, and cost all suggest they are last resort devices where they work.

I'm sure an In-Line Draft Inducer would work. They actually have the motor outside the the stove pipe and just "paddle blades" in the single all stove pipe. But, unfortunately, I don't have the clearance needed before I had to switch to double wall pipe to meet fire codes. (at least at the inducers I have seen).

One thought I have (when I duct the house from the room) is to place a powered vent blowing air from upstairs to the room with the stove. My state enforces the National fire code so each duct penetrating a floor must have a fire damper. (This requirement doesn't apply if the ducts are permanently and continuously attached to a UL listed furnace that automatically shuts off if it's temperature exceeds 165F) That isn't the case with with my Pioneer thus I need automatic fire dampers for each duct.

I also ordered new CO detectors with the newer 70 ppm (1-4) hour standard, 30-69 ppm if for 30 days and a near instant alarm if CO is at a "get out" level.. They are rated for 10 years and have a 10 year battery installed) My existing ones were almost ready to expire (beep if too old) anyway. CO alarms made some time ago had no provision to alarm you the sensor was too old and potentially useless.

Too much work or $$$ doesn't make sense. I can just turn on my propane furnace when I hit this situation. The heavy heating $eason doesn't have this problem so most heating $ are coal :)

 
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Post by gerry_g » Thu. Apr. 16, 2015 11:48 am

2001Sierra wrote:Wouldn't blocking the baro or covering it help to increase over fire draft? Just a suggestion, anyone have an opinion?
No way, if one blocks the baro they are removing a vital safety device.

 
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Post by blrman07 » Thu. Apr. 16, 2015 11:57 am

A barometric damper is NOT a vital safety device. It is put in to help reduce the amount of draft going through a solid fuel device.

 
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Post by gerry_g » Thu. Apr. 16, 2015 12:12 pm

blrman07 wrote:A barometric damper is NOT a vital safety device. It is put in to help reduce the amount of draft going through a solid fuel device.
Tell that to my inspector and fire insurance company. The stove must be installed per instructions.

Excess draft can increase combustion air intake and over fire the burner, likely causing the fire to migrate closer to the stove wall.

 
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Post by Lightning » Thu. Apr. 16, 2015 1:32 pm

I like the idea of using a vent blower to push air down into the basement from above. Seems like it would help.

Other than that, could you install a vent to the outside, in the basement?

 
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Post by blrman07 » Thu. Apr. 16, 2015 3:23 pm

gerry_g wrote:
blrman07 wrote:A barometric damper is NOT a vital safety device. It is put in to help reduce the amount of draft going through a solid fuel device.
Tell that to my inspector and fire insurance company. The stove must be installed per instructions.

Excess draft can increase combustion air intake and over fire the burner, likely causing the fire to migrate closer to the stove wall.
Where are you getting this stuff from. I AM AN INSPECTOR FOR AN INSURANCE COMPANY as well as a pastor.

How in the double blue blazes can a fire inside a stove migrate closer to the stove wall unless it jumps out of the stove and flies over to it?

 
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Post by gerry_g » Thu. Apr. 16, 2015 4:14 pm

blrman07 wrote:
Where are you getting this stuff from. I AM AN INSPECTOR FOR AN INSURANCE COMPANY as well as a pastor.

How in the double blue blazes can a fire inside a stove migrate closer to the stove wall unless it jumps out of the stove and flies over to it?
Clearly you are no an inspector in MA , read the Pioneer's manual for UL approval or deal with states that require full compliance to the manufacture's installation documents (which requires a barometric damper). My town's inspector actually looks at the installation documentation which just happens to require a barometric damper. No signed off permit = no fire insurance here. Perhaps PA doesn't enforce the National Fire Code as do many other states. But you ignore the installation instructions during inspection? It specifies clearances and a barometric damper.

Any increase in combustion air beyond that which the stove is designed for can easily allow the the fire to creep up the sloped burner at high burn rates. That would migrate the combustion closer to the stove's wall, feed opening and hopper.

At least I'm not in Maine which, for some time has required heat recovery ventilation to maintain air quality! That is $$$.


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