Questions on Coal Gun basics

Re: Questions on Coal Gun basics

PostBy: coaledsweat On: Tue Apr 19, 2016 1:13 pm

What he means is the fire won't die if unpowered for 2-3 days unlike other appliances that would be cold as a stone in that time frame. At idle they burn close to nothing because the combustion air can't feed it. It is unique design.
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

Re: Questions on Coal Gun basics

PostBy: lsayre On: Tue Apr 19, 2016 5:46 pm

coaledsweat wrote:What he means is the fire won't die if unpowered for 2-3 days unlike other appliances that would be cold as a stone in that time frame. At idle they burn close to nothing because the combustion air can't feed it. It is unique design.


Mine burns only between 15 and 16 lbs. per day during the summer, and some percentage of that (4 lbs. per day perhaps?) is for heating the homes DHW. As I stated earlier there is no timer and there is no need for one. The Coal Gun does not have a blower. It has a fan, and its function is significantly different from that of a blower.
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Blaschak Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)

Re: Questions on Coal Gun basics

PostBy: tmbm50 On: Wed Apr 20, 2016 7:09 am

Ah, ok that makes sense. Thats pretty cool it will keep a fire for 2-3 days. My stoker is out in 30 minutes without power.

New question, maybe this should be a new thread.

How are you guys with boilers controlling the return water temp? From what I was told the return water needs to be around 160 degrees or else we risk condensation.

I'm not sure how you figure what your return water temp will be given any specific size heat exchanger or even X of hydronic piping.

For example, lets assume a standard radiant tubing setup. You use a mixing valve to reduce the temp to 120 degrees but then the return water is X degrees cooler. And I couldn't find a mixing valve that increase the water temp. Wouldn't the return temp depend on all kinds of things like air temp around the piping, what type of heat plate is used on the pipe etc

And it gets even more confusing with an air heat exchanger. One unit said the formula to determine Delta-T was Delta-T = Q/500 x F
If you take there largest 5 ton unit it works out to this

130,000 / (500 * 13gpm). I'd have to run the pump at 13 GPM.....that seems way too fast.
tmbm50
 

Re: Questions on Coal Gun basics

PostBy: McGiever On: Wed Apr 20, 2016 7:33 am

One way to not shock a boiler with too cold of return water is you could run a "Primary-Secondary" loop system. That way the colder return of the secondary loop is gradually blended in with already hot primary loop.
McGiever
 
Stoker Coal Boiler: AXEMAN-ANDERSON 130 "1959"
Coal Size/Type: PEA / ANTHRACITE
Other Heating: Ground Source Heat Pump
Stove/Furnace Make: Hydro Heat /Mega Tek

Re: Questions on Coal Gun basics

PostBy: coaledsweat On: Wed Apr 20, 2016 7:48 am

tmbm50 wrote:How are you guys with boilers controlling the return water temp? From what I was told the return water needs to be around 160 degrees or else we risk condensation.

That is not going to happen in a coal boiler.
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

Re: Questions on Coal Gun basics

PostBy: tmbm50 On: Wed Apr 20, 2016 10:36 am

coaledsweat wrote:That is not going to happen in a coal boiler.


Really? The manual for the S130 uses scary and ominous language that return water should NEVER be under 150 degrees.
Last edited by coaledsweat on Wed Apr 20, 2016 12:34 pm, edited 1 time in total.
Reason: Quote box
tmbm50
 

Re: Questions on Coal Gun basics

PostBy: lzaharis On: Wed Apr 20, 2016 11:13 am

Stokers run with that low a temperature in the summer months and I ran my hand fed like that when the weather was not very demanding and I had return water temps of 130-150 degrees all winter long when
the winter was at its worst some years.

What you have to avoid like the plague is the problem called "thermal shock" which is what you really have to worry about which causes metal fatigue in the steam chest of the boiler. by returning the cooler water to the sump of the boiler it allows the cooler water to be heated and rise to the top of the steam chest.

By installing the circulator on the top of the boiler steam chest it also reduces air bubbles to an almost nothing problem as long as the system is piped properly.

Summer operating temperatures are are typically 160 high 140 low anyway so the issue is control more than anything and deciding if you want to use the coal gun the year round for hot water in the off season months as it will keep the firebox warm and risk of condensation to a near zero amount as cold steel loves to attract moisture.

Otherwise you want to keep a drop light with an incandescent bulb lit in the boiler and or a pail or two of Damp Rid in the fire box to suck up the moisture that will occur naturally. Adding a box of uncooked white rice in a bucket will help do that too but at slower rate.
Last edited by lzaharis on Wed Apr 20, 2016 3:51 pm, edited 1 time in total.
lzaharis
 
Stoker Coal Boiler: Keystoker KAA-4-1 dual fuel boiler
Coal Size/Type: rice
Other Heating: kerosene for dual fuel Keystoker

Re: Questions on Coal Gun basics

PostBy: coaledsweat On: Wed Apr 20, 2016 12:33 pm

tmbm50 wrote:Really? The manual for the S130 uses scary and ominous language that return water should NEVER be under 150 degrees.

That is true but it won't cause condensation is my point. It may fatigue the metal over time.
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

Re: Questions on Coal Gun basics

PostBy: greenftechn On: Fri Jun 03, 2016 4:43 pm

Sorry to be late to the conversation. Manuals are written to be very conservative by nature. The number in the newest manual is 140, and that is still very conservative. You CAN still get condensation in a Coal Gun, but the exhaust is almost completely dry, so it is highly unlikely. It is not just temperature of return water that is of concern, but the volume + temperature. Run that Coal Gun cooler in the summer and save coal! You're just using the internal coil or DHW zone, so the energy draw is minimal.
greenftechn
 
Stoker Coal Boiler: Coal Gun S130
Hand Fed Coal Stove: Alaska Kodiak
Coal Size/Type: Nut
Other Heating: Wood Gun
Stove/Furnace Make: Alternate Heating Systems
Stove/Furnace Model: E100

Re: Questions on Coal Gun basics

PostBy: greenftechn On: Fri Jun 03, 2016 4:52 pm

Lighting the Coal Gun is easier than any other coal boiler.

https://www.youtube.com/watch?v=2Leyy13wq9w
greenftechn
 
Stoker Coal Boiler: Coal Gun S130
Hand Fed Coal Stove: Alaska Kodiak
Coal Size/Type: Nut
Other Heating: Wood Gun
Stove/Furnace Make: Alternate Heating Systems
Stove/Furnace Model: E100

Re: Questions on Coal Gun basics

PostBy: coaledsweat On: Fri Jun 03, 2016 7:45 pm

What are those brackets each side of the observation port?
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

Re: Questions on Coal Gun basics

PostBy: lsayre On: Fri Jun 03, 2016 8:05 pm

They are the hangers (mounts) for the Tombstone Cover. You can see it here: http://www.alternateheatingsystems.com/coal-gun.html
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Blaschak Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)

Re: Questions on Coal Gun basics

PostBy: Yanche On: Sun Jun 05, 2016 1:11 pm

greenftechn wrote:Lighting the Coal Gun is easier than any other coal boiler.

https://www.youtube.com/watch?v=2Leyy13wq9w


I just use my oxygen acetylene torch directly on the pea coal. Works well not charcoal required.
Yanche
 
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea

Re: Questions on Coal Gun basics

PostBy: greenftechn On: Mon Jun 06, 2016 7:24 am

Yep, that acetylene torch is going work quite well. Enough heat to ignite the coal and off you go. The charcoal will help when using propane with no O2 boost. Literally takes seconds.
greenftechn
 
Stoker Coal Boiler: Coal Gun S130
Hand Fed Coal Stove: Alaska Kodiak
Coal Size/Type: Nut
Other Heating: Wood Gun
Stove/Furnace Make: Alternate Heating Systems
Stove/Furnace Model: E100