Large Hot Water System Efficiency

 
waldo lemieux
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Post by waldo lemieux » Mon. Jan. 07, 2013 6:28 pm

oops :oops: I guess that had already been suggested


 
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Short Bus
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Location: Cantwell Alaska
Stoker Coal Boiler: Kewanee boiler with Anchor stoker
Coal Size/Type: Chestnut / Sub-bituminous C
Other Heating: Propane wall furnace back up only

Post by Short Bus » Mon. Jan. 07, 2013 6:52 pm

Efficiency,
Coal burns, heat is transmitted to the water in the system.
All heat in the water ends up in the house, unless you run the pipes outside, to or from a shop or somthing.
So you have three things to work on.

1. Combustion efficiency
2. Heat tranfer into the water.
3. Heat loss from house to ouside.

Combustion efficiency, correct air evenly applied to the coal bed, and no extra air being sucked though the boiler by the chiminy. If your chiminy is centrally located it will radiate heat into the house also, but extra air thought the boiler is bad.
Heat transfer to the water, clean the heat exchanging surfaces of your boiler, once a month for me.
Heat loss from house, probalby about a million ideas about how to fix that, and every home has this issue.

 
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franpipeman
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Location: Wernersville pa
Stoker Coal Boiler: efm 520 stoker fitzgibbons pressure vessel
Hand Fed Coal Stove: harman, russo
Coal Size/Type: rice
Other Heating: alpine propane condensing boiler radiant floor

Post by franpipeman » Mon. Jan. 07, 2013 7:09 pm

http://www.hvaccalc.com/main.asp
49$ used it for ac and heating three houses. I was trained the old way in the mid 70s which was tedious this does Fine $50.00 is nothing

heat loss program for a limited time and 49$ you can do all the calc you like and its user friend shows duct size and maybe pipe size

 
CoalBurner5
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Post by CoalBurner5 » Tue. Jan. 08, 2013 3:55 pm

Okay so set me straight on a few questions.

1.) can someone please explain exactly how to check for draft? (YES PLEASE GIVE ME EVERYTHING, fan on if so for how long.)
2.) I take a reading at the door through the hole and I want it to be .02 is that correct?
3.) also the second reading I want that to be between my barometric damper and the flue collar on the boiler correct?

Again please give me step by step because I KNOW I NEED IT.

 
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Rob R.
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Stoker Coal Boiler: EFM 520
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Post by Rob R. » Tue. Jan. 08, 2013 4:40 pm

CoalBurner5 wrote:Okay so set me straight on a few questions.

1.) can someone please explain exactly how to check for draft? (YES PLEASE GIVE ME EVERYTHING, fan on if so for how long.)
2.) I take a reading at the door through the hole and I want it to be .02 is that correct? Yes.
3.) also the second reading I want that to be between my barometric damper and the flue collar on the boiler correct? Yes, about 12" from the flue collar if possible. Look for -0.04 to -0.05"
Generally speaking, the boiler should be at operating temperature and you should let the stoker run (burn) for 20-30 minutes before you use the draft reading to adjust the barometric damper. As a baseline, I would set the baro weight at #5. Note that the weight goes on the left side if the damper is on a horizontal piece of pipe...right side if vertical.

Before you adjust anything I suggest that you make sure the boiler, stoker burn plates, flue pipe, and chimney are clean. It is supposed to be mild weather for the next couple days, so this is a good time to shut down the unit and do a proper cleaning. It is also a good time to check that the feed/air ratio is correct.

5 teeth and 4.5 air is a pretty decent starting point for rice coal. Once the boiler is up to temperature and has been running for a few hours, put a load on it and make the stoker run for 30 minutes...at that point you should have about 1-2" of ash around the fire. If you have slightly more ash, reduce the air to 4.25...if the burning coal is creeping onto the burner ring around the plates, increase the air to 4.75 or so. Repeat the "test burn" and tweak as necessary until you are satisfied that the fire appearance is correct...double check the draft after the fire is tuned.

 
CoalBurner5
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Post by CoalBurner5 » Tue. Jan. 08, 2013 4:52 pm

Alright I've checked my draft and just like everyone says the draw is .02 at fire box door. I drilled a hole on the "T" at the collar. and the draw there is also .02. how is that possible?

 
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Rob R.
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Post by Rob R. » Tue. Jan. 08, 2013 5:37 pm

Pull the tubing off your draft gauge and blow through it...it could be obstructed.


 
CoalBurner5
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Post by CoalBurner5 » Tue. Jan. 08, 2013 5:48 pm

Already checked for obstruction.

.02 at door and at collar.

 
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Rob R.
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Post by Rob R. » Tue. Jan. 08, 2013 5:57 pm

Is that with the stoker running?

 
CoalBurner5
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Post by CoalBurner5 » Tue. Jan. 08, 2013 6:04 pm

Fire was running for 30 mins. Then I shut down the system and immediately took readings. .02 at both locations.

 
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Rob R.
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Post by Rob R. » Tue. Jan. 08, 2013 6:06 pm

Take the reading with the stoker running.

 
CoalBurner5
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Post by CoalBurner5 » Tue. Jan. 08, 2013 6:12 pm

Ok and put air at 0?

 
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Rob R.
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Post by Rob R. » Tue. Jan. 08, 2013 6:18 pm

No, set the air where EFM recommends for the feed rate. 4 clicks & 4 air, or 5 clicks & 4.5 air. I would run 5 clicks and 4.5 air for now.

 
CoalBurner5
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Post by CoalBurner5 » Wed. Jan. 09, 2013 2:37 pm

Okay so I bumped up the feed to 5 air is set at 4.5. I have a good fire going. I killed the power and took a reading. I got the same reading at both the door and collar.

So about the only thing I can think of is bump my coal up to maybe 6 and push the air to efm standards and hope that more coal will hold a stronger fire and use less coal.

Any other thoughts?

 
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Rob R.
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Post by Rob R. » Wed. Jan. 09, 2013 2:43 pm

Why do you keep shutting it off before you take the reading?! The stoker must be running when you check the draft reading at the door, and at the flue pipe.


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