Can't Get Enough Heat Out of VF3000

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Hillside
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Post Wed. Nov. 21, 2012 7:53 am

I installed a VF3000 last fall heated with it ,, on days in the 20's couldn't keep water above 130 now on nights in the 20's it is the same this year now. The house is well insulated trying to heat 1500 square keep heat shut off in some of the rooms doesn't help. Not real happy with the Harman so far. Anyone have any ideas. I have it hookin a loop with the oil furnace the hand fired Harman worked fine this way.. But certainly not impressed with the stoker so far colder days are coming. Any help would be greatly appreciated I am in central PA.

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KLook
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Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Other Heating: Gas boiler backup/main
Stove/Furnace Model: VF 3000
Location: Harrison, Tenn

Post Wed. Nov. 21, 2012 8:01 am

Hello Hillside, I also run one as do a few others in here. Mine is in Maine however and it does struggle as I am heating more then that and it is colder up there. Still, it does work. This has been discussed many time in here. How to get maximum potential out of any boiler. First of all, do you have your draft controlled? You can't afford to lose heat up the chimney. It has to have a borometric damper. Then do you have it adjusted to maximum burn potential. OR is it putting hot coal right to the edge before it falls into the pan after extended run times? The next thing I would do is reduce the speed or flow of water when it is calling for heat. Depending on the circulator, you may be overwhelming its ability to catch up with all the cold water returning. And this is a function of what kind of radiation you have. What is it by the way? Just a few things to start with, It should work fine in your climate.

Kevin

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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 Wed. Nov. 21, 2012 8:23 am

Do you have underground piping between the boilers?

Do you have the feed rate adjusted to get the maximum amount of BTU's out of the stoker?

Hillside
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Post Wed. Nov. 21, 2012 8:28 am

The furnaces are within 3 feet of each other ,, the fire is hot til it is ready to drop off the grate. I had a plumber check the draft I ordered a draft gauge of my own yesteday..

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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 Wed. Nov. 21, 2012 8:29 am

You aren't the first person to complain about the output of a VF3000, but it seems odd that it can't handle a 1500 sq. ft "well insulated" house in Central PA.

What do you have for radiation?

Hillside
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Post Wed. Nov. 21, 2012 8:37 am

Its the radiation 3 inches off the floor with fins on it I don't know the technical name for it. THe oil furnace worked fine and so did the Harman hand fired furnace but got expensive cutting wood .. and not as acessable as it once was..

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steamup
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Stoker Coal Boiler: Axeman-Anderson AA-130, Keystoker K-6
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Coal Size/Type: pea, buck, rice
Location: Napoli, NY

Post Wed. Nov. 21, 2012 8:46 am

What water temp are you trying to maintain. It needs to be the same as the oil setting. Lower water temp means lower heat output at the radiation.

Is the boiler cycling or running full out?

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KLook
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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: Harrison, Tenn

Post Wed. Nov. 21, 2012 8:48 am

How about a picture of the setup for the heat mechanics in here to view. I am not one of those, just an owner that had to learn more then I wanted about hydronics because of an undersized system.

The biggest changes I made to improve my system was install an injection system for my radiant slab(28x30) and reduced the flow from all zones. A 007 will wash all the hot water(50 gal) out of a VF3000 in about 5 min. Aprox. as I don't remember the actual GPM, and it takes longer then that to ramp up the fire to full heat and then it is a function of how fast it can transfer it to the cold water.

Kevin

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Hillside
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Post Wed. Nov. 21, 2012 8:50 am

THe Harman runs continuously trying to keep up,, the boiler is turned back so it doesn't run but I turn it back up at times to get the house warm as the Harman won't get the water temps up to 160. If it maintains that I can keep the house warm but it has a hard time getting to 130 .. NOT a happy camper with the stoker right now..

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KLook
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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: Harrison, Tenn

Post Wed. Nov. 21, 2012 8:53 am

Doesn't sound right, it will do better then that. patience ;)

Kevin

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KLook
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Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Other Heating: Gas boiler backup/main
Stove/Furnace Model: VF 3000
Location: Harrison, Tenn

Post Wed. Nov. 21, 2012 8:54 am

What temp does the Harman run up to before shutting off?

Kevin

What kind of radiation?

Pacowy
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Stoker Coal Boiler: H.B. Smith 350 Mills boiler/EFM 85R stoker
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Post Wed. Nov. 21, 2012 9:06 am

Hillside wrote:The furnaces are within 3 feet of each other ,, the fire is hot til it is ready to drop off the grate. I had a plumber check the draft I ordered a draft gauge of my own yesteday..
If the coals are hot until they drop off the grate it needs more air. There should be a 1-2" band of ash before it drops off.

Mike

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KLook
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Posts: 3650
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: Harrison, Tenn

Post Wed. Nov. 21, 2012 9:10 am

the coals are hot until they drop off the grate it needs more air. There should be a 1-2" band of ash before it drops off.
That depends on feed rate, but you are right, it could have low feed and low air. I had mine wide open pretty much so I didn't think of that.
Hillside, look at the left side of the blower motor that feeds air under the fire, Is it blocked by a small bent round flap or is it wide open?

Kevin

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Rob R.
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Posts: 11507
Joined: Fri. Dec. 28, 2007 4:26 pm
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 Wed. Nov. 21, 2012 9:45 am

How is the feed rate adjusted on this thing? Threaded rod like a Keystoker?

Like Mike said, it sounds like it needs more air. I would feed as much coal as you can while maintaining 1-2" of ash at the end of the grate. It is good that you ordered a draft gauge, when you get the air cranked up it is important that the firebox is still negative compared to the room.

Pacowy
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Posts: 2810
Joined: Tue. Sep. 04, 2007 10:14 pm
Stoker Coal Boiler: H.B. Smith 350 Mills boiler/EFM 85R stoker
Coal Size/Type: Buckwheat/anthracite
Location: Dalton, MA

Post Wed. Nov. 21, 2012 9:57 am

KLook wrote:
the coals are hot until they drop off the grate it needs more air. There should be a 1-2" band of ash before it drops off.
That depends on feed rate, but you are right, it could have low feed and low air.
I don't think the objective of having the band of ash depends upon the feed rate. Having hot coals go off the end is a sign that there's not enough air relative to coal regardless of the feed rate.

I agree that making sure the air is wide open and flowing properly is important to getting the max possible output. Once on my Mag I noticed reduced output, and found that the combustion blower was not properly seated. The air chamber clean-out lever should periodically be operated, too. Making sure the heat exchange surfaces are free of ash accumulation might help, and it couldn't hurt to check the sizing and quality of the coal. Too much undersized coal tends to impede the flow of air through the fire. It might be worth trying "big" rice or buckwheat to see if better high-end output can be achieved.

Mike

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