Need Help Burning Coal in a Harman SF 260

KTM250 · Post by **KTM250** » Thu. Dec. 24, 2009 7:37 am

Hello all, I am about at my wits end with this Harman SF 260 boiler. It has been a nightmare from day one from installing the chimney to getting it plumbed in. Now I am struggling to get long burn times to keeping the water up to temp. I am also trying to heat my domestic hot water (with an external hydo stor tank) and that looks like it is not going to work well at all. I have tried all kinds of different settings from draft , to air flow controls on the ash pan door and shaking the bed differently. Not sure what is going on here but all I can say is that hand fired coal stoves suck. I have been using a stoker for about 8 years and never had problems. I was hoping that maybe there are some SF 260, 160 or 360 owners out there that may be able to help me. I do know that if I would have started burning coal with this unit I would have stopped a long time ago.
Thanks Bob

WNY · Post by **WNY** » Thu. Dec. 24, 2009 7:54 am

I would thats the problems with hand fed boilers, maintaining a good even temperature, it will vary with the amount of coal, burn, draft, etc.....others with one, will probably chime in....

What kind of water temps are you getting? do you have a pic of your install? what type of controls are you using.?

Robby · Post by **Robby** » Thu. Dec. 24, 2009 8:36 am

Good Morning and Merry Christmas,

If I can help. We heat with SF360. Sub-bituminous and wood, not much wood. Heating 2200 sq.ft bungalow w/2000 walkout basement in Alberta, Canada. Not so cold a climate as many would have you believe, but a long,long way from Florida.

You tell me what I can relate and I will.

Robby

coalkirk · Post by **coalkirk** » Thu. Dec. 24, 2009 9:02 am

Bob,

Don't despair yet, there's lots of expertise here to get you dialed in. That SF260 kicks out 130K BTU's and unless you are trying to heat a mansion, it can and will work. You just need some tweaking, fine adjustment and balancing. Also know that Harman under rates their boilers. If it's rated at 130K, I guarantee you it's producing more than that.
Tell us about your original heating system ( radiators, baseboard), tell us about your house (size, age, insulation), tell us the details of your settings etc. on the coal boiler(temp, chimney, barometric damper, size coal you are using, burn times). Pics of the installation would be very helpful.

Terry

By the way, I'm heating 4,000 sq. ft. with a 95,000 BTU stoker boiler.

Post by **Rob R.** » Thu. Dec. 24, 2009 10:00 am

I don't have an SF260, but I do run a 160k BTU hand-fed boiler. I am heating over 3000 sq. ft and my domestic hot water with an indirect tank. Before we suggest things to check it would help if you provided more detail about your system, pictures would be very helpful as well. I have a few questions that should get the ball rolling.

What kind of BTU load are you putting on the boiler?
How is your system plumbed?
What are you using for controls? What are the current settings?
What do you have for a chimney setup? Has the draft been checked?
What size coal are you burning? How much does the boiler consume in 24 hrs?

Jaeger · Post by **Jaeger** » Thu. Dec. 24, 2009 10:05 pm

KTM,

Don't despair, I have a SF360 and feel your pain. Last year we had trouble getting it going then had an over fire. I finally got down to tweaking it and had the exact problem your having now. The longest I could burn was like 3-4 days. Most mornings it was completely out. I was so beat up about the boiler last year I was thinking, I can't believe it is this hard.

I am in no way experienced in using coal and am really just in my first "real" season. There is so much experience and knowledge on this forum I'm sure you can get it straightened out. These guys are the best and will get you going right. I'm sure being Christmas Eve you are not going to get too much info right away but use the search function.

I ended up putting on a barometric damper (based on recommendations here) and just fired the boiler up last Saturday. I was dreading it! This was the first fire since the damper install. I had to play with it a bit the first day or two and spent several hours checking it and finally think I'm there. There is a learning curve with getting your system to run properly. I'm heating a 4000 sq ft. house and have 3 zones in my house heated by 2 air handlers, + radiant floor under all my tile (4 additional thermostats), and a 80 gallon hot water heater. Just this week I figured that my 3 programmable thermostats on the zones are not my friend. I have now set them to hold the temp I want so that they don't keep changing 5 times at different hours a day for water. I keep the downstairs at 68 during the day, the upstairs at 65. At night I turn the upstairs to 67 and the down to 65. I have been filling the boiler in the morning, around 1pm, and at 11pm. I found that having my automatic draft door adjusted about 1/2 of it's total and the idle air adjustment less than 1/2 half has done it for me.

I've been using 4 buckets (5 gallon) of stove sized coal worth a day. And am so happy with the SF360 this year. This is 10x easier than my old wood insert in my last home, plus it heats everything!!

Trust me spend time searching this site, before you throw in the towel. You will learn so much about how to get that boiler running. Good luck and have a great Christmas!!

Jaeger

JB Sparks · Post by **JB Sparks** » Thu. Dec. 24, 2009 11:23 pm

KTM, as has been mentioned above, there is a learning curve to running a hand fed but, hang in there. With the help of everyone on this site you will get there.

I have an SF 160, I heat 1800 sqft. and domestic hot water. I burn nut coal and get an easy 12 hour burn time per load. I'm using about 40 to 50 lbs. per day. The following are my settings: The A350 is set at 165* which on my unit is running 10* off so the automatic daft door closes at 175* then the water temp will drift up to about 185* to 190* and hold, this due the idle draft setting which is set at just under half the diameter of the idle ports or to be specific it measures 3/16" from the high point on the arc of the port to the flat edge of the adjustment blade. The baro is set at .03 to .04 WC. You do need to have a menometer to set the draft accurately.

If your SF 260 has the fire bricks laid in horizontally on the long edge, You should fill the fire box to the top of the fire bricks and then mound higher in the middle that should give you at least a 12 hour burn time.

Last season I did have trouble with the Super stor DHW sucking all the heat out of the boiler water so, I installed a by-pass advised by Freddy ( Maine monitor)and it work out well once I had the ball valves adjusted so that the boiler water temp would only drop about 12 to 15*. If you install a by-pass with a ball valves, start with the valves opened about 45*. My final settings are with the valve in the supply pipe opened 45* and the by-pass valve opened about 50*. This stopped the big heat suck.

Hope this helps out a little, -Jeff

KTM250 · Post by **KTM250** » Fri. Dec. 25, 2009 11:10 am

First off Merry Christmas to all. A quick update. Got up this morning and fire is just about out. Had to start all over with putting wood in to get it going again!!!!

The people that have asked me question I will get back to you on my setup. As a quick try I will use JB Sparks settings and see what happens. When I get a minute I have a bunch of question for the people that have responded. Again Merry Christmas.
Thanks
Bob

KTM250 · Post by **KTM250** » Sat. Dec. 26, 2009 9:01 am

Ok I will try to answer some of the questions. I am trying to heat a 2400 sqft home and my domestic hot water with an external tank. The house was built in 1989 has 2x6 outside walls and insulation value that was standard for that time. Not sure what it is. I have three zones, one up stairs, one for the downstairs and one for the hot water tank. The heat is through baseboard hot water. I have the boil temp set at 175 (which closes the flapper door on the ash pan door) and the over temp control kicks the downstairs zone on at 185. My chimney is a double wall pipe up about 20 ft and the boiler is in my basement. I have a barometric dampener which I originally set to .05 as per Harmans instutions. I am setting it with a manometer. I am burning nut coal. Burn times seem to be the problem. If I try to go 12hrs (which I need because of my work schedule) it will be burned down or not burning so that I have to start over with wood or it takes 3 or 4 hrs to get it going again. I only have ½ hour in the morning to get this going for the day. At first I thought that the coal was not burning up all the way, usually the front of the bed would be out and just the back would be burning. After looking at it again I believe that the coal is just burned out for the most part in the front. As far as how much coal am I using, not really sure, again not sure how much to put in and it might be 3 to four 5 gal bucket loads a day. Which seems like a lot. I sure hope that this thing is not going to burn 100 lbs a day because then it becomes almost as cost effective to just fire up the oil boiler. The other thing is that the weather really has not been that cold here.
MarkViii not sure what you mean about BTU load? I have the boiler plumbed in so that I can run the coal or the oil by themselves or have the coal run with the oil. Right now I am just running the coal. The controls are set like I stated about and they are Johnson Controls A350, Y350 and S350.
I will stop this post here and see what Idea’s you people have and see if there are other questions. I did set my air controls and the Baro like JB said and it does seem better. Right now outside is 35 and the downstairs is running 75 with the thermostat set at 68. This is due to the fact that the boiler is going above my high temp setting and dumping into the downstairs zone.
Thanks Bob

coalkirk · Post by **coalkirk** » Sat. Dec. 26, 2009 9:23 am

Most homes built in 1989 are going to have at least R30 in the attic and with 2x6 exterior walls, you should have R19 walls. That's pretty good. I would try turning down your aquastat from 175 to say 155 for a trial day or so. also, when you load the boiler up, are you loading it fully to the top of the firebrick?
I'm not familiar with the controls on the SF series. Maybe someone with experience with these boilers can offer some suggestions as to the optimum settings. For the home and load you describe, that boiler should be more than adequate. It sounds like tweaking and learning curve issues which you will surely overcome.

Jaeger · Post by **Jaeger** » Sat. Dec. 26, 2009 10:39 am

KTM,

I am running my aqua-stat temp at 160 and am considering dropping to 150. The hotter the demand for water the faster the burn. I did a search and found quite a few folks running theirs in the 140-150 range. When I'm at 160 it never goes over 180 and never below 140.

Keep plugging away you'll get it.

Jaeger.

KTM250 · Post by **KTM250** » Sat. Dec. 26, 2009 2:03 pm

Coalkirk, I fill to the top of the firebrick and then some. Jaeger you and Coalkirk would like me to drop my boiler temp. My concern with that is my domestic hot water. If I lower the temp Im sure that it would heat the house fine. Are you heating your hot water with yours.
Thanks Bob

Jaeger · Post by **Jaeger** » Sat. Dec. 26, 2009 2:12 pm

Bob,

Yes, got a 80 gallon domestic hot water in the mix also. I'm running all of the stuff I listed off mine.

Works like a champ. My hot water heater is set at 110 and we have no trouble with the coal keeping up with it and the rest of the house demands.

Just keep tweaking it. It's 49 outside today and I was worried about the draft with the "warm" spell. I'm trying to have mine burn out today because we are traveling. I filled it last night at 1030pm, and it is still maintaining 160!! I want to switch it over to oil while we are away for a few days.

You'll get it just keep playing with it!! I'm so pleased with the performance this year I want to build another coal bin when the weather finally breaks!!

KTM250 · Post by **KTM250** » Sat. Dec. 26, 2009 2:25 pm

Jaeger very good. The only difference I see is that my hot water is set to 140. Isn't 110 a little low? So I will go down and set the temp to 160 and see what happens. Another question when you shake you grates do you shake them until you see glowing in the ash pan? That is one thing that I have a hard time doing, maybe its because I have burned the coal out. Again thanks to all here. If this forum was not here I would have pulled the plug.

Thanks Bob

JB Sparks · Post by **JB Sparks** » Sat. Dec. 26, 2009 2:31 pm

KTM, I would set the S350 at 20* and the adjustable differential at 15*. I'd also set the A350 down to 170* because you will always get a 10* drift in water temp after the ash door damper closes. with the S350 set at 20* you won't be having the dump zone coming on so much and your first floor will stay closer to the thermostat setting.

You are correct in that the front of the fire box burns up first. I use a poker and rake the coals around the edges of the fire box and then use the shaker. Don't forget, short choppy strokes on the shaker so as not to dump the coal bed. Also when loading fill it to the top of the fire bricks and mound up the center. With a house as well insullated as your's, you should be getting 12 hour burns easily.

One other point, if you get a water temp drift more than 20* after the ash damper closes, close down the idle port just a touch more. 1/16" at a time. It gets pretty touchy when you get close to the right settings. The objective is to stop the temp. drift but still have enough air for long idle times. Check the ash door damper and make sure when it's closed it is flat against the square housing, if not you need to loosen the three 1/4-20 bolts and adjust it so it is against the housing on all four sides.

I would also set the baro at -.03 to .04., .05 will let the fire run a little to hot using up your coals. You should be using no more than 50# a day. If after you get the burn times up to twelve hours and you feel that your still using too much coal you could consider installing a fire box reducer available from Harman for you SF260. - Jeff