AHS S130 stoker boiler

I have learned very much already just reading this forum, but I still have a long way to go. I currently have a wood fired boiler that we heat our three year old house with. We have radient floor heat and like it very much. Our house has about 1800 sq. ft. and easy to heat, but cutting wood isn't as fun as it was 25 years ago. I am about to switch a AHS 130 coal stoker boiler and retire the wood boiler. The wood boiler has a combustion blower that turns off when the water in the boiler reaches 140 degrees. The problem with the wood boiler is the boiler water temp. keeps rising, when the circluating pump and the blower are off. With the new coal boiler, what will keep the same problem from happening?

Hello Rick, welcome to the forum. The continued rise in heat from wood is one of the reasons I am now using coal almost exclusively.

My boiler is a hand feed, not a stoker feed, so I have large quantity of coal in the firebox. Inspite of this, once my aquastat is satisfied, my water temperature rarely rises more than 10-15*. I could control it much more closely with a more sophisticated combustion blower/air control, but It is good enough for my system.

The AHS 130 is a sophisticated stoker feed unit, We have several members on the forum with this unit. I'm sure that the water temp control is much better than on my home-grown boiler.

Take a look at this link: http://nepacrossroads.com/viewtopic.php?t=1070

Greg L

I'm on my third season with a AHS S-130. There is a boiler water aquastat with adjustable low and high settings. Plus an additional high safety cut off aquastat. There is some overshoot, maybe 10 degrees but it's not a problem. In any event you could reduce the high set point lower. I have my high set point at 190. At this temperature the combustion blower shuts off. If the circulator pumps are still running heating my house or hot water there is not much overshoot. If there is no demand it overshoots to about 200. Safety is set for 210. As far as I know my safety switch has never tripped. What method do you use to lower the water temperature circulating in the floors. Manifold mix return and hot supply water? You could run the S-130 at a much lower temperature to minimize the problem by using a Honeywell AQ475A Aquatrol Outdoor Temperature Compensator for Boilers. This will adjust boiler water temperature based on outdoor temperature. Low outside temperature = higher boiler water temperature. I bought one ($200) but have installed it yet.

Yanche

hi everyone. this is my 50th day with my ahs s-130 coal gun. i am heating 3700 sq feet of space made up of 1 two story house and a cottage. plus a boiler room and a 12x12 coal boiler shed. i have started to trust this unit now . i am burning between 60 and 80 pounds a day of pea coal. the tenants keep the thermastats about 72. thats as high as they go. i had 2 thermastats fail this fall. may go to 68 degree thermastats. anyway i am getting a 2 to 3 day burn with the largest hopper. glad i did not put a auger in . i have found 2 pieces of coal bigger thank fist so far in the coal bin. i built a 12x12x8.5 feet coal bin. filled it with 21-22 ton of coal. i am hoping to get 2 years of burning out of this. the coal bin sits on the former lehigh valley railroad. used to be coal cars from bernice go through here kinda ironic. the fuji controller has been a big help in starting the coal fire. I think Yanche is right a outdoor tempurature reset would help. i do not get anyover shoot on my system set at 180. i run it through the oil boiler for backup. i may bypass the boiler next year. i have a domestic coil in the s-130 i am not using right now. thats all for now. may walk the railroad looking for old coal later. ...... own 3/4 of a mile of it

Glad to learn you are pleased with the AHS S-130. I certainly like mine. It's my third season and it's almost paid for in oil cost savings. Think through any changes in the series piping of the two boilers. The advantage of series connection is the unused boiler is keep warm, eliminating a cold fire condition in the oil boiler and any condensation condition in both. The disadvantage is you have a larger "radiator" in the boiler room. If you heat your summer domestic water with oil you would not want the coal boiler to be a "radiator" then. I use isolation valves so that in summer the coal boiler is not in the circulation loop. I have a indirect hot water heater, i.e., boiler water is pumped to it. In summer the controls on the oil burner are switched so that it only fires when the hot water heater thermostat requires it. This greatly reduces the standby losses. Additional savings oil savings could be achieved by reducing the oil nozzle size. This would make the oil boiler more efficient. But the down side is it also reduces it output BTU capacity. If the oil boiler was properly sized for the coldest total heat load on it's own, it would now not be able to meet the demand on the coldest days in winter. There is a lot of trade offs to think about and there is not one correct answer.

I grew up in NJ where the Lehigh Valley railroad ran right through the center of town. My father told me in the great depression how they would oil or wax the tracks so the train would slow down. Townspeople would then climb the coal cars and shovel off coal to heat their homes. I also remember the train slowing down as the mail bag was tossed off and the outgoing mail bag was grabbed off it's hook. The engineer always blew the train whistle when prompted by us kids. Great fun.

Take a look at the Axeman-Anderson auger design. It can't clog or over feed by design. It's a large diameter pipe with a hollow spiral welded to the ID of pipe. I've not been able to find another source for it.

How has the fuji controller been a help in starting the coal fire. Where is the temperature probe located? Can it be damaged by the moving grate or ash?

Yanche

hello The fuji thermalcouple is good to 1200 degrees. it sits in the coalash . turning the grate on around 120 degrees and stops around 140. while the combustion blower is on. when the combustion blower goes out temps rise to about 190 -220 . A good thing about this is during the summer i could probably keep it going all summer heating hot water coil in oil boiler.
when the unit is first starting up. the fuji detects the heat and ash. so you have a good idea what the fire is doing. the first time i started the fire i thought i put it out after adding to much coal. but the fuji just kept climbing in temp so i knew i did not put it out.
you can buy a fuji controller and solid state relay on ebay for about 100 dollars. uses a k-thermacouple and also get the fuji manual online at there website. only bad thing about ahs is the manual. its pretty useless but the phone support is great. plus i just printed all the sheets on the controlls from online sources.
I to have live next to the tracks most of my life. My dad retired from ACF where they built tank and hopper cars. ARE house was next to a 3 track siding. I have learn somethings about this secondary branch of the lehigh that ran from Luzurne , Rickets , Lopez,Dushore and on to Towanda. mostly from the ARHS. anthracite railroads historical society.
When i was building the coal bin and building the truck ramp up to it i hit what looked like a small loading platform made from stacked blue stone and a couple of huge cut flagstone on top. this was all covered with dirt . big suprise for me. it took everything the massey had to move these. sorry so long. love coal - trains - history and the USA...

Hi all happy new year

had a surprise this morning when i went to load the coal gun.
found the guts to my baro damper on the other side of the shed. 7 feet away. the rain cap was still on the chimney . and everything looks like it was working fine. baro was open almost all the way all the time. my draft was .01 to .02 below the baro and .03 to .04 above . i know sometimes when the combustion blower stops i get a few wooof inside the burn chamber until the fire calms down. anyone ever had this happen? glad i have my pipe screwed and cemeted. thanks

There have been a few times when I've found my barometric damper partially detached from its pivot point. My AHS S-130 in a detached shop building from my house so I've never been a witness to what happened. Obviously, some rapid ignition of coal gases occurred. I've pondered the conditions that would cause this. I liken the conditions needed like those when a hand fired stove is stoked with fresh new coal. A hot spot of glowing coal ignites the gases given off by the newly added coal. One needs to be an owner of a "coal gun" boiler and familiar with the boiler operation to understand how this set of conditions could occur. It seems to me the trigger event would be the aquastat reaching the high limit trip point. The combustion blower would have been running and coasting to a stop. So there would be good hot coals to serve as a ignition point. Now if new fresh coal enters the firebox at just this instant and the coal have some "fines" with it you could have ignition of the new coal gases. I have seen when fresh coal is added all of a sudden. As if the coal from the gravity feed hopper got stuck and then just let go. This jerk might release the coal "fines". I addition when the combustion blower stops the oval flapper door is making a transition from the closed position to the open draft position. Transient conditions are always the most difficult to understand and I suspect this is one of them. I have made sure all my stove pipe, stove pipe tees and elbows and barometer dampers are all securely fastened. Perhaps our barometric damper is is not adequate for coal use. I do know there are differences for coal and oil vs. gas boilers. I'll do a bit more research.

Yanche

hello yanche

thanks for the repley. i feel alot better now. i agree with you on the coal gases. i do get alot of fines sometimes. my baro damper i used to leave open almost all the way. now that it is gone it still drafts great. i am just going to leave it alone for awhile to see what happens.
i have my boiler in a 12x12 shed with my 4 wheller. it heats 2 apartment houses. i talked to my insurance agent about insuring it even though it is not a code boiler. they do not have a problem with it as long as it is not in the main structure. cost 36 dollars. thanks again for your help.

mwcougar

Thanks for all the info, but you are starting to worry me. I spent what I thought was alot of money for my new boiler and now you are telling me things I should get, and every once and awhile it blows-up!

Yanche wrote:There have been a few times when I've found my barometric damper partially detached from its pivot point. My AHS S-130 in a detached shop building from my house so I've never been a witness to what happened. Obviously, some rapid ignition of coal gases occurred. I've pondered the conditions that would cause this. I liken the conditions needed like those when a hand fired stove is stoked with fresh new coal. A hot spot of glowing coal ignites the gases given off by the newly added coal. One needs to be an owner of a "coal gun" boiler and familiar with the boiler operation to understand how this set of conditions could occur. It seems to me the trigger event would be the aquastat reaching the high limit trip point. The combustion blower would have been running and coasting to a stop. So there would be good hot coals to serve as a ignition point. Now if new fresh coal enters the firebox at just this instant and the coal have some "fines" with it you could have ignition of the new coal gases. I have seen when fresh coal is added all of a sudden. As if the coal from the gravity feed hopper got stuck and then just let go. This jerk might release the coal "fines". I addition when the combustion blower stops the oval flapper door is making a transition from the closed position to the open draft position. Transient conditions are always the most difficult to understand and I suspect this is one of them. I have made sure all my stove pipe, stove pipe tees and elbows and barometer dampers are all securely fastened. Perhaps our barometric damper is is not adequate for coal use. I do know there are differences for coal and oil vs. gas boilers. I'll do a bit more research.

Yanche

I noticed in the 1953 US Dept of the Interior, Bureau of Mines study of the Axeman-Anderson Anthratube (a unit similar to the AHS coal gun), it stated that when burning #1 buckwheat coal in the unit, the air over fire must be increased to burn off CO. This is done by drilling a 7/16 hole in the sight tube door of the combustion chamber. This is necessary because the unit's air flow was designed only for burning pea coal. (Buckwheat was to be an alternative in "emergencies") It states: "without this air, the carbon monoxide in the products of combustion would frequently during start-up periods, build up to some 13 percent or enough to create an explosive mixture. The mixture would ignite and cause a 'bump' or small explosion. "

I believe Yanche is absolutely correct in that the volatiles, under certain circumstances, and in certain combinations, which are hard to detect, will cause that combustion bump.

I believe the fines might approximate the buckwheat coal described in the study. Their greater surface area for the release of volatiles and the reduced combustion rate from restricted air flow might put the CO/air mixture into the explosive range.

Most likely an auger feed would reduce the amount of fines picked up versus the pail or shovel. Perhaps drilling holes in the pail would allow the fines to shake out and prevent them from going into the hopper. In your situations, do not drill the hole in the sight door unless you are burning buckwheat and only with mfr confirmation--please!

Just a suggestion from a rookie theoretician still waiting for his boiler to be completed at A-A!

(Yanche-pm me with your address and I'll send you a copy of this study FYI.)

mikeandgerry wrote:I noticed in the 1953 US Dept of the Interior, Bureau of Mines study of the Axeman-Anderson Anthratube (a unit similar to the AHS coal gun), it stated that when burning #1 buckwheat coal in the unit, the air over fire must be increased to burn off CO.

I should have written:

"...it stated that when burning #1 buckwheat coal in the unit, the air over fire must be increased."

The reason for increased air is to move the concentration of CO in the CO/air mixture in the combustion chamber out of the explosive range.

Rick, to put what I've observed in perspective, it's not much different from a backfire from a mis-adjusted (combustion air) oil burner boiler. That has also blown off my barometric damper. I checked the model of barometric damper I have installed. It's a Fields RC model, a model that's listed for both oil and coal use. So that's not the issue. I was concerned that it might have been a Fields model MG-1 that is only listed for gas use. Looking at the Fields Catalog the physical construction of the ones approved for coal use are somewhat different. Some look more robust in design. The RC model is not one of them. Anyone have experience with one model vs. another?

Also NFPA 211, the fire code for chimneys, has stringent requirements for the construction of the stovepipes. What they call "vent connectors". There is a requirement for withstanding the "positive pressure" of the connected appliance.

Yanche

hi Rick

i would not be scared of this boiler. i feel good about mine now. all coal stove have some kind quarks. it is very simple to operate and realiable.

yanche my baro i bought at a local hardware store. the box said for coal or wood.

i will be checking for another one. also my stove pipe goes directly up off of the boiler no elbows.

also my flapper towards the top leaves a 1/16 gap. which i feel is fine . which now i guess would work for the transition time.

have fun cougar

I now have a wood boiler where my new 130 is going to go. As I understand it the 130 has a five inch chimney outlet. The chimney for my wood boiler is now eight inch. How and what combination of adapters do you think would be best to go from five inch to eight inch?