my Harman 160 Won't burn all night

[HowlingMad]

It should be a simple request, but I can't seem to figure it out, perhaps some of you can help me. With the help of this forum, I installed a used Harman SF 160 last year. Although everything works just fine, I can't seem to keep the fire running all night and simply feed it more wood in the morning. Is this common? I've never owned a wood boiler before. I run the same wood in my home Avalon Olympic wood stove so I doubt it's anything to do with the wood. I've tried continually turning down the temperature (now at 120 for the damper open temp) and the adjustment holes are almost shut completely.

Forgive the very basic question, but should I be able to load it with wood and expect to build a fire from scratch every morning? What should I check? Is it leaking air from somewhere else?

Thanks in advance.

 

[bigburner]

What is the heating load? Is the thing ever idling, that heat is going some where.

 

[ISeeDeadBTUs]

I'd sugest putting the name of your unit in the post title.

 

[HowlingMad]

What is the heating load? Is the thing ever idling, that heat is going some where.

I'm only heating about 800 sq ft (roughly 8000 cubic feet) right now with approximately 48' of baseboard traveling through roughly 150' of 3/4 copper. The walls and ceiling are well insulated and the boiler is centrally located. The temperature outside is around 20 and inside its mid 50's.

Not sure exactly what you mean by idling, but if you mean is the auto-damper ever closed, then yes, a fair amount of the time. The return pipes are always quite warm, as if there wasn't enough baseboard to dissipate the heat.

I've got a fair amount of buildup in the stove which suggests that it's running fairly lean as well.

The aquastat is set at 120 which opens the damper at 138 and closes it at 145. The circulator comes on at 130 and goes off at about 100.

Yesterday I cleaned up the breather dials on the front to ensure they were not leaking air and also replaced the rope seal on the ash door. As far as I can tell, there are no other air leaks anywhere. This morning the fire was still dead.

I'm stumped.

Thanks for any help or suggestions!

 

[HowlingMad]

I'd sugest putting the name of your unit in the post title.

Good suggestion. Title has been changed.

Thank you.

 

[sparke]

So many variables but lets say your unit is working as intended. I believe your boiler has shaker grates? If so it is hard to get long burn times because the coals fall through the grates instead of forming a deep coal bed which last hours after the fire is out. That said, is there is anywhere you can bank the coals so they wont fall through the grates? Also, try using large unsplt round logs when you make the last fill of the night. Try mixing in some hard (anthracite) coal. I suspect your unit is a better coal burner then it is a wood burner but I have no experience with that brand boiler... Good luck!

 

[sparke]

Looking at your last post, something is way out of whack with your aquastat settings! Typically we run 170-180* water through baseboards. I am surprised you are getting any heat the way your aquastats are set. Also, with those setting you have creosote making machine... Lets get to the bottom of that issue before we go any further...

 

[ISeeDeadBTUs]

Though I'd seen Harman's talked about on Hearth, I didn't know anything about them. I just looked at the Harman site.

Look, I'm no heating technician, so we're clear on that.

Did you used to have a different boiler before the Harman? If so, what temps were the supply and return water?

It may be 20ish outside now, but the thermometer's headed upside down after the storm! I'd be burnin the wood in a chimnea in the middle of that 800 [/]. Probably do better than your current situation hh:

 

[HowlingMad]

I bought the unit used and the previous owner had it set around 180 or so, running mostly coal I think. Since I have no need to have the shop more than 60 degrees, I turned it down, and then turned it down again. I kept turning it down so that the fire would make it through the night, but it seemed 120 was in fact a creosote factory so I stopped there. Since I don't need the shop more than 60, it seems like a waste of wood to heat the boiler more if you can 't shut it off like a gas or oil boiler.

I'm not sure how turning up the temperature can make the fire last any longer, but I've seen stranger things and in the interest of trying all solutions, I'll turn it up to 150 (making between 168-175) for a day or two.

By the way, this is an entirely new system to this building, there was no previous boiler setup.

I ran some tests today to document what the aquastat settings were. Hopefully it will be of use to someone else in the future.

 

[HowlingMad]

Well, still no fire this morning. I'm very curious to hear if any other Harman owners can make it through the night with their fire. I'd really like to hear what you use for settings.

Sparke mentioned the shaker grates as a possible issue and I think he may be on to the larger issue. Anyone tried anything to solve this issue? Perhaps another grate to reduce the size of the holes?

 

[sparke]

A believe your boiler is a non gasser and does not have secondary combustion. This is what we call a smoke dragon. That does not mean it isn't a well made boiler it just means that there is not much technology present to make the most of the smoke/heat going up the chimney. It is very similar to my old Memco which I could only get 4-6 hours burn time. In the Memco I put firebrick in the bottom and it did help. You need to make sure the fire can still get enough air.

Realistically I think you have 3 choices: Put some firebrick over the grates and see if that helps. Use coal (I think this is your best bet). Incorporate heat storage, this will allow you to run your boiler straight out and clean. The down side is you have to make a new fire every day.

Keep in mind I am guessing your boiler has no secondary combustion making it a low efficiency boiler. If that is the wrong assumption then you need to talk to a factory rep for technical help or find someone that has the same boiler as yours. I have not seen anyone on this site that has a Harman 160. Good luck.

 

[ISeeDeadBTUs]

I know nothing about coal. I've heard that the difference between it and wood is amazing though. The only thing I would say there is be safe and make sure you know what you're doing hh:

As Sparke stated, your water temps don't seem correct. I have radient, with outside control. I can tell you that the water going out to the tubes when it's as cold as it was last night is way higher than 130. WAY!! And though I'm no heating technician, I believe your BB should be hotter than my radiant. You said the gauy that was running this unit had it set somewhere around 180? Set it similarly. I mean, if you can't heat 800 [/] with baseboard, there is a serious problem! The windows are closed, yes?!? ;-)

My unit is quite different from yours . . .but . . . what fuel are you putting in it? I think you will find that your unit is going to be more efficient with water temps ~180 than 130.

 

[HowlingMad]

A believe your boiler is a non gasser and does not have secondary combustion. This is what we call a smoke dragon. That does not mean it isn't a well made boiler it just means that there is not much technology present to make the most of the smoke/heat going up the chimney. It is very similar to my old Memco which I could only get 4-6 hours burn time. In the Memco I put firebrick in the bottom and it did help. You need to make sure the fire can still get enough air.

Realistically I think you have 3 choices: Put some firebrick over the grates and see if that helps. Use coal (I think this is your best bet). Incorporate heat storage, this will allow you to run your boiler straight out and clean. The down side is you have to make a new fire every day.

Keep in mind I am guessing your boiler has no secondary combustion making it a low efficiency boiler. If that is the wrong assumption then you need to talk to a factory rep for technical help or find someone that has the same boiler as yours. I have not seen anyone on this site that has a Harman 160. Good luck.

Very intelligent post, thank you. I think you've directly answered my question about burn time. I think you're right about the secondary combustion, although I thought that was part of the mid 80's EPA requirement that they all had to have that? In any case, it seems fairly unsophisticated to me so I'm guessing you're right.

Good idea on the firebrick. If I can find thinner ones, I'll try that next.

I heat the house with wood from scrounging all year long, so as much as I'd like to use coal, it doesn't fit right now. I may buy a couple bags just to see how it changes things.

By heat storage, do you mean adding something like a water tank? I'm very new to this game, so forgive the dumb questions.

Thanks for all the help gents. I'll report back after the firebrick test.

 

[bigburner]

My unit is different that yours, well every ones for that matter. I have a fire brick burn chamber, I load it with wood and set the fan timer for two hours, then when it shuts off the air is drawn threw the fan and in to the fire box. The water temp doesn't control anything. I leave a bed of ash in the bottom and last night it went 14 hours and there still a football size red hot log in there.{water temps were falling off, i do have storage} But as far as a relight I have gone 24 hours and found enough coals to ignite the small pieces I throw in first. last year I never relight a fire even when cleaning out the ashes i found hot coals and would set them aside for the relight. Fire brick is your friend.

 

[Como]

I do not know anything about them either, but I have heated with coal.

In volume terms you are going to get much more heat from coal than wood. And it is going to burn a lot hotter.

The firebox size is about 3 cu ft, say with good hardwood about 500,000 btus max.

Divide by say 2 for efficiency so that is 250,000 btus max, less if you are using scrap soft wood and less if you can not pack it full.

You could probably do a rough on line heat loss calculation to see what your load is and whether there is a any match with those numbers.

They rate it the same for wood and coal, which seems a bit odd.

 

[frank t]

i have a harman 260 and heat 4000 sf all radiant slabs. you should try setting unit to run 180 degrees . coal will run atleast 12 hours. adjust door so it is open enough to keep up not much more . top air on door just a 1/4 turn each. with wood i get 4 hours burn then reload. you should have a dump zone when your idleing. i keep coal fire going for most of cold wheather ,mild temp for wood.

 

[HowlingMad]

Hey, a fellow Harman owner. Good to know it's not just me struggling to keep the wood fire burning. I have a few questions about your answers.

... adjust door so it is open enough to keep up not much more .

Do you mean the dials, the aquastat, the little swivel adjustment on the damper door or something else?

... you should have a dump zone when your idleing.

Sorry for my ignorance, but what's a dump zone or where can I find more about it?

Thanks for the response.

 

[frank t]

first set aqwastat at 180,the door a 1/4 turn for coal only. the small holes on flapper door cover about 3/4 of hole. a dump zone should be able to drop boiler between house heating . your controls that came with boiler can be set for a little past set temp. i have a 53k unit heater in garge to dump heat. mostly needed with coal b ecause it takes time to start a new fire. when i burn wood i heat house and let die out ,do not let idle with wood for long periods of time. your contols will let you use your main zone to dump heat but it will over heat house.

 

[frank t]

you bought used ,do you have manuels. you can call for more help 570 877 5783.

 

[HowlingMad]

Thanks for the reply and advice. I wonder if you could help me understand the statement below a little.

a dump zone should be able to drop boiler between house heating .

I think I understand that a dump zone is a loop to dump excessive heat, but I'm still wrestling with the sentence above.

It's worth noting that the barn I'm heating is quite a ways from the house.

 

[HowlingMad]

you bought used ,do you have manuels. you can call for more help......

I was able to find some info on the web, but it assumes some knowledge and I'm coming up a little short. I'll probably take you up on your offer for help this week.

 

[HowlingMad]

Realistically I think you have 3 choices: Put some firebrick over the grates and see if that helps.

Well, Sparke called it; the fire bricks are getting me through the night at 160 degrees (178-185 actual). It wasn't quite a full night since I fed it around 11 and checked on it at 5am, but there was still plenty of embers left so I think this solves my problem.

Many thanks to everyone who contributed to my not having to start a new fire every morning and hopefully have less creosote to worry about.