Can't Get Enough Heat Out of VF3000

Stoker Coal Boilers automatically feed the coal and have controls and pumps just like any conventions boiler. They are intended to be used as a primary heat and often have domestic hot water coils as an added bonus. They can be set up independently or in dual sytem with your existing oil/gas boiler. They can accommodate both hot water base board or steam plumbing.
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Rob R.
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Stoker Coal Boiler: EFM DF520
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: Lehigh Rice
Other Heating: Dad's 1953 EFM Highboy
Location: Chazy, NY

Post Thu. Jan. 31, 2013 11:20 am

It sounds like this stoker design is very sensitive to coal size and fines. If the coal is too small or contains excessive fines you can't get enough air through it, and if the coal is buck size the draft must be adjusted differently to avoid fumes spilling into the boiler room. I guess spec-size rice with minimal fines is the only way to go.

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coalkirk
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Stoker Coal Boiler: 1981 EFM DF520
Coal Size/Type: anthracite/rice coal
Location: Forest Hill MD

Post Thu. Jan. 31, 2013 1:09 pm

I have never been able to successfully burn buck in the vf3000. It will burn back into the hopper.
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Burning rice coal in a 1981 EFM DF520, nut coal in a hand fired Jotul 507.

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Rob R.
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Posts: 11341
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Stoker Coal Boiler: EFM DF520
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: Lehigh Rice
Other Heating: Dad's 1953 EFM Highboy
Location: Chazy, NY

Post Thu. Jan. 31, 2013 1:35 pm

coalkirk wrote:I have never been able to successfully burn buck in the vf3000. It will burn back into the hopper.
:fear:

It sounds like this stoker is pretty "fussy" about coal size.

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KLook
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Posts: 3631
Joined: Sun. Feb. 17, 2008 1:08 pm
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Other Heating: Gas boiler backup/main
Stove/Furnace Model: VF 3000
Location: Chattanooga, Tenn

Post Thu. Jan. 31, 2013 8:02 pm

I did burn a few bags but did not notice an improvement. It did not burn back into the hopper but mine runs a little harder then coalkirks. Hard to burn back when it is pushing full steam all the time.

Kevin

syncmaster
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Posts: 300
Joined: Sat. Apr. 19, 2008 1:29 pm
Stoker Coal Boiler: harmanVF3000 Coal/oil option
Coal Size/Type: Rice
Stove/Furnace Make: VF3000
Stove/Furnace Model: Harman VF3000
Location: long Island,NY

Post Tue. Feb. 05, 2013 9:15 pm

I can't believe these posts!
I have been running my VF3000 for 4 years winter and summer.
I am on long island heating a 2400 sqft ranch and no problems keeping the whole house at 71 degrees when it is 0 out.
I did have a few problems with it over the years.

one time I noticed the hot coals was not straight across , one side was full with hot coaals and the hot coals angled to nothing on the other side. (a little bit like yours looks)
I bailed out all the coal in the hopper into a empty garbage can, when I got down to the pusher I see a 3/4" round magic marker. all the paint was worn off from the pusher pushing it up towards the grate and it would roll back down when the pusher moved back, so no coal could drop down because the magic marker filled that space.

after that I installed a piece of chicken wire across the hopper to catch any junk mixed in with the coal.
over time it stopped some pieces of over sized coal and a golf ball sized rock.

So empty your hopper and see that you don't have something stuck in front of your pusher.

another time I couldn't get a good flame and I found a piece of cellophane stuck in the blower cage blocking some fins.

I will post a picture the flame when my vf3000 is cranking
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KLook
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Posts: 3631
Joined: Sun. Feb. 17, 2008 1:08 pm
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Other Heating: Gas boiler backup/main
Stove/Furnace Model: VF 3000
Location: Chattanooga, Tenn

Post Tue. Feb. 05, 2013 10:21 pm

I can't believe these posts!
I have been running my VF3000 for 4 years winter and summer.
I am on long island heating a 2400 sqft ranch and no problems keeping the whole house at 71 degrees when it is 0 out.
I did have a few problems with it over the years.

one time I noticed the hot coals was not straight across , one side was full with hot coaals and the hot coals angled to nothing on the other side. (a little bit like yours looks)
I bailed out all the coal in the hopper into a empty garbage can, when I got down to the pusher I see a 3/4" round magic marker. all the paint was worn off from the pusher pushing it up towards the grate and it would roll back down when the pusher moved back, so no coal could drop down because the magic marker filled that space.

after that I installed a piece of chicken wire across the hopper to catch any junk mixed in with the coal.
over time it stopped some pieces of over sized coal and a golf ball sized rock.

So empty your hopper and see that you don't have something stuck in front of your pusher.
I also have a screen because of junk in my coal.
Now, as to your success in running it on Long Island, I bet you have all baseboard fin tube? I have noticed that with the fin tube and the toe-kick heaters, I can not appreciably reduce the temp of the water, so I reduce the flow. The radiant is set up as an injection system and gives the boiler plenty of time to recover. But when those big radiators in the basement call, all bets are off. My problem is to many kinds of radiation. I think the VF3000 suffers from not being able to get up and running soon enough and it cannot recover once it is down. At least mine wont. The trick is to put out hotter water in the severe weather and I like my backup boiler kicking in automatically at a preset temp. The only other option for me in Maine would be an outdoor reset/temp control to ramp it up automatically and I would like a wind direction and speed factor also. Back to running a rocketship instead of a boiler. ;)

Kevin

syncmaster
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Posts: 300
Joined: Sat. Apr. 19, 2008 1:29 pm
Stoker Coal Boiler: harmanVF3000 Coal/oil option
Coal Size/Type: Rice
Stove/Furnace Make: VF3000
Stove/Furnace Model: Harman VF3000
Location: long Island,NY

Post Wed. Feb. 06, 2013 5:43 pm


I also have a screen because of junk in my coal.
Now, as to your success in running it on Long Island, I bet you have all baseboard fin tube? I have noticed that with the fin tube and the toe-kick heaters, I can not appreciably reduce the temp of the water, so I reduce the flow. The radiant is set up as an injection system and gives the boiler plenty of time to recover. But when those big radiators in the basement call, all bets are off. My problem is to many kinds of radiation. I think the VF3000 suffers from not being able to get up and running soon enough and it cannot recover once it is down. At least mine wont. The trick is to put out hotter water in the severe weather and I like my backup boiler kicking in automatically at a preset temp. The only other option for me in Maine would be an outdoor reset/temp control to ramp it up automatically and I would like a wind direction and speed factor also. Back to running a rocketship instead of a boiler. ;)

Kevin
yes, I have baseboard fin tube. Reading your question jogged my memory....when I first installed the vf3000 and the outside temp was around 20 degrees , I some times heard complaints that there isn't enough hot water for showers.
I realized that the vf3000 dosen't have a lo limit cutoff which shuts down the circulator when the boiler water temp gets below a certain point.
so I went on ebay and bought another johnson S350 and plugged it into the side of the 3 johnson controlers supplied with the VF3000. I set the extra s350 to open when the temp falls below 155 degrees. That extra s350 opens the common wires to the zone valves. so now the vf3000 water temp dosen't fall below 155degrees so I can make DHW all the time.

the VF3k starts stoaking when the boiler temp is below 160 , at 155 the zone valves are disabled but not the zone valve for DHW ( the boiler water is still hot enough to make DHW)
when the coal fire builds and the boiler temp gets above 155 the heating zone valves are enabled.

This set up might help you, just disable your baseboard at 155 but let your radiant continue working.
Then when the boiler gets above 155 your baseboard will be enabled.

I will post a picture of my set up
001_1.JPG

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KLook
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Posts: 3631
Joined: Sun. Feb. 17, 2008 1:08 pm
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Other Heating: Gas boiler backup/main
Stove/Furnace Model: VF 3000
Location: Chattanooga, Tenn

Post Wed. Feb. 06, 2013 7:04 pm

Hey, thanks for the input, and I agree with your logic on the extra s350. I however took that Johnson crap of my boiler after an overheat episode last winter and put honeywell aquastats in place and built my own stoker control unit. I now have a timer like the Keystokers and a cube relay in the original box making things stoke. So far, other then a free used aquastat not working properly, things are going well for my son who is running it this winter. He is enjoying the cheap heat and that makes me happy to. :)

Kevin

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franco b
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Hand Fed Coal Stove: V ermont Castings 2310, Franco Belge 262
Baseburners & Antiques: Glenwood Modern Oak 114
Coal Size/Type: nut and pea
Location: Kent CT

Post Thu. Feb. 07, 2013 4:02 pm

Reverse aquastats have only been around for over 50 years so I guess the manufacturer never heard of them. Don't the designers of these things ever use them?

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KLook
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Posts: 3631
Joined: Sun. Feb. 17, 2008 1:08 pm
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Other Heating: Gas boiler backup/main
Stove/Furnace Model: VF 3000
Location: Chattanooga, Tenn

Post Thu. Feb. 07, 2013 6:35 pm

Those fancy blue boxes with leds and intergrated functions look cool but leave you stumped when something goes wrong.

RICHARD2
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Posts: 27
Joined: Sun. May. 04, 2008 1:34 pm
Stoker Coal Boiler: KA2
Location: Upstate New York

Post Sat. Feb. 09, 2013 1:48 am

Hillside wrote:I want to thank everyone for there help so far... as of now as long as I sift the fines off the coal it has been working but the temps up til now have been above what I was having problems at. So when the temps drop I will let everyone know how it is working..
Read all 9 pages of this thread; saw that lots of suggestions were made and tried, but I somehow missed the takeaway.

What was the cause, and the solution to "Hillside"s problem? Was it just the fines in the coal?

His caveat in the above quote -- that the temperatures are above what they were when he was having problems -- leaves some doubt as to whether just sifting the coal is the answer.
Sometimes a little experience upsets a lot of theory.
Ditto for manufacturer's advertising claims.

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KLook
Member
Posts: 3631
Joined: Sun. Feb. 17, 2008 1:08 pm
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Other Heating: Gas boiler backup/main
Stove/Furnace Model: VF 3000
Location: Chattanooga, Tenn

Post Sat. Feb. 09, 2013 7:48 am

I am going to go on memory, but I think small coal, to many fines, restricted the airflow. On top of that, the coal is not the best.
The problem was restricted airflow. It can be accomplished in several ways and maybe more then one was the culprit.

Bad fan
air restrictor closed on fan
air escaping around bed before getting to combustion holes
excessive fines plugging coal flow
excessive fines plugging holes in bed
excessive fines plugging area under bed
fan not seated correctly
Not enough coal being pushed
squirrel cage blower loose on shaft
Plugged chimney but this is usually accompanied by other things (poor draft/CO detector screaming)

Basically, there is a laundry list of things to look at before concluding poor coal. All of these pusher block stokers work the same way. After burning for a few years, most will know immediately the quality of the coal by how it burns on the bed. Height of flames for instance with a given air setting will be something experience will teach. Somewhere back there someone posted that the flames should reach into the tubes, a good rule of thumb for a full power burn with good coal. I remember that was helpful to learn from someone else when I was learning to burn.

Kevin

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dkononczuk
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Posts: 132
Joined: Tue. Feb. 05, 2008 5:07 pm
Stove/Furnace Make: Harman VF3000
Location: NEPA

Post Sat. Feb. 09, 2013 7:49 am

I'm using exact same setup on my VF3000 with similar temp settings and it works great.
syncmaster wrote:

I also have a screen because of junk in my coal.
Now, as to your success in running it on Long Island, I bet you have all baseboard fin tube? I have noticed that with the fin tube and the toe-kick heaters, I can not appreciably reduce the temp of the water, so I reduce the flow. The radiant is set up as an injection system and gives the boiler plenty of time to recover. But when those big radiators in the basement call, all bets are off. My problem is to many kinds of radiation. I think the VF3000 suffers from not being able to get up and running soon enough and it cannot recover once it is down. At least mine wont. The trick is to put out hotter water in the severe weather and I like my backup boiler kicking in automatically at a preset temp. The only other option for me in Maine would be an outdoor reset/temp control to ramp it up automatically and I would like a wind direction and speed factor also. Back to running a rocketship instead of a boiler. ;)

Kevin
yes, I have baseboard fin tube. Reading your question jogged my memory....when I first installed the vf3000 and the outside temp was around 20 degrees , I some times heard complaints that there isn't enough hot water for showers.
I realized that the vf3000 dosen't have a lo limit cutoff which shuts down the circulator when the boiler water temp gets below a certain point.
so I went on ebay and bought another johnson S350 and plugged it into the side of the 3 johnson controlers supplied with the VF3000. I set the extra s350 to open when the temp falls below 155 degrees. That extra s350 opens the common wires to the zone valves. so now the vf3000 water temp dosen't fall below 155degrees so I can make DHW all the time.

the VF3k starts stoaking when the boiler temp is below 160 , at 155 the zone valves are disabled but not the zone valve for DHW ( the boiler water is still hot enough to make DHW)
when the coal fire builds and the boiler temp gets above 155 the heating zone valves are enabled.

This set up might help you, just disable your baseboard at 155 but let your radiant continue working.
Then when the boiler gets above 155 your baseboard will be enabled.

I will post a picture of my set up
The attachment 001_1.JPG is no longer available
Attachments
IMG_0033.JPG
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User avatar
KLook
Member
Posts: 3631
Joined: Sun. Feb. 17, 2008 1:08 pm
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Other Heating: Gas boiler backup/main
Stove/Furnace Model: VF 3000
Location: Chattanooga, Tenn

Post Sat. Feb. 09, 2013 7:57 am

I noticed screwdrivers to get the covers off to tinker with the settings. Do you put all 4 in tight or cheat and use 2 diagonally? :P I also got tired of getting in there and messing with the settings. Honeywells are setemandforgetem. Until one fails and that is extremely rare.
I actually suspect that my sensor failed, as the differential was way off after a meltdown. I guess I am old school and like the simple open/close with an adjustable diff. of the mechanical(no power) Honeywells.

Kevin

RICHARD2
Member
Posts: 27
Joined: Sun. May. 04, 2008 1:34 pm
Stoker Coal Boiler: KA2
Location: Upstate New York

Post Sat. Feb. 09, 2013 9:24 am

I did note all those possible causes spread through the 9 pages of this thread, but your summary of them gives all of us a concise troubleshooting checklist -- Thank You.
Sometimes a little experience upsets a lot of theory.
Ditto for manufacturer's advertising claims.

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