Tarm 502

[kart42]

The number Codehead posted is correct and is for Bioheatusa in Lyme, NH. I called on Dec 22 and ordered and received the baffles on Dec 23. Really outstanding service. The cost was $255 plus shipping (to Vt that was about $22). I found a bulletin from HS Tarm on the coal baffles somewhere on the net and printed it. I think I have the PDF file on my computer. The prints are not too clear but if you are interested I can post the PDF (or the link if I can find it). The baffles have significantly improved coal burning. However, keeping them in place is a bit challenging. I think the design could have been better. I am also worried about the longevity of the cold rolled steel plate that holds the base of the cast iron baffles. It sits very close to the base of the fire. Time will tell I guess.

 

[glhenry56]

Cokehead / Kart42,

Thanks for the coal grate info. I'd like to see the PDF files or a link if you could. Might be a project for next year.

Did my midwinter firetube cleaning tonight - lots of soot on the oil burner side. I have 2 particular issues that have been a thorn in my side when it comes to the oil burner: 1) "blinding over" of the oil burner air inlet with dust, and [I believe] inaccurate O2 readings by burner technicians when servicing my unit. Either or both have resulted in several really messy soot events over the years. The dust buildup issue is something that I can control, but if it isn't regularly vacuumed away or wiped off, it can creep up on me fast. With insufficient air to the oil burner, it starts to smoke, the soot rapidly plugs the firetubes, and soon I'm smelling sulfur in the basement and have a nasty sooty mess to clean up. Ugh!

My second concern is really a result of the draft inducer - one of those unintended consequences of making an improvement. For the inducer to work properly, it must pull a quantity of room air into the fan (which is located close to the boiler outlet). Thus there is a hole near the flue gas outlet. Unless the burner tech inserts his gas probe all the way into the boiler itself, it is likely that some of the room air is being drawn in to the flue pipe (by natural draft), diluting the sample. O2 reads higher than it should, and the burner tech is likely to restrict air to the burner. Since I'm rarely at home when this is done, I've relied on notes, and as I can tell from trying to describe the situation in writing, the message may not be getting through.

In any case, I'm going to try to attach some photos of the inducer for those who might be interested. It has served me well, and I recommend it as a way to reduce smoke blowback and as an assist in starting a fire. Don't know where or even if these are still available, but I would certainly think so. It is a Fasco brand, Type U63, 1600 RPM, 115V, 1 amp, continuous duty.

 

[kart42]

I found the pdf file with the coal baffle info. The pictures are not very clear. If I had a chance to do it over I would take some pictures before I put the pieces into the furnace. The part shown in figure 1 (of the pdf file) is made out of cold rolled steel. It sits on top of the rails that hold the shaker grates in the front of the firebox up against the separation baffles (those that separate the wood and oil combustion chambers. This piece performs two functions. 1. Hold the coal baffles themselves 2. Seal the space behind the coal baffles from air in the ash pit (the air must flow through the coal, burn and then go over the top of the coal baffle, down behind the coal baffle and then up the firetubes. The base of the cast iron baffles sit on the cold rolled steel plate and go up almost vertically. They are held away from the upper front of the combustion chamber by a couple of narrow cast projections at the top. They need to be away from the wall so the hot combustion gasses can flow down behind them and then up the firetubes. If you have your original Tarm manual the parts explosion page shows the coal baffles and the support plate in the upper left hand corner of the page (item 50, coal baffles) in my copy.

The baffles have had a really positive effect on my Tarms ability to burn coal. I am still learning, but I can now say for sure that without these baffles keeping a coal fire for a number of days would have been really difficult.

Paul

The pdf file was to large to include here. Now that I know what they are the picture in the Tarm furnace manual is descriptive. However, only a few weeks ago I didn't understand and it was not clear. Perhaps my description above will help with understanding, at least a bit.

 

[glhenry56]

I spent a few minutes and located the parts diagram in my Tarm manual. With your description, I now have a good idea of how it works. I also have a couple of drawings of the separation baffles and protection bricks that Craig Issod sold me back around 1991. I'll scan and post them sometime soon.

 

[TimfromPittsburgh]

Hi Fellow Tarm 502 Owners,

I just foiund and registered on this forum today. Great information here.

I have a Tarm 502 that I have been burning wood and coal in for 11 years. My boiler has the coal grates with external shaker handle. I bought the coal baffles when I purchased the boiler. I burn wood except when the temperature is consistently below 20 degrees (the entire month of January this year) I burn coal.

I would like to share some lessons learned from my experience burning coal:

1. The coal baffle is essential for burning coal.

2. Either anthracite or bituminous coal can be burned in the boiler. I prefer anthricite because it is smokeless. For me the "nut" size works best. Main thing is to get good quality coal. If the coal contains a lot of rock you will need to let the fire die and clean the grates frequently. The grates just won't allow big rocks to fall through into the ash pit. Coal that forms clinkers also clogs up the grates and chokes off air flow. With good coal I can run the boiler for 4 or 5 days before the grates clog up.

3. While burning coal I shake the grates often. When shaking the grates I continue shaking until I am getting hot coals falling into the ash pit. Some unburned coal falls into the ash pit but it helps prevent the grates from clogging. When I empty the ash pit I pick out the unburned coal and throw it back into the firebox.

4. When I burn coal, I close the secondary air control.

I just recently installed a draft inducer in the flue pipe. I wish I had done it a long time ago. The draft inducer really helps with smoke control when loading wood into the firebox. When burning coal, I can successfully burn coal at higher outside temperatures.

Hope this helps.

Tim from Pittsburgh

 

[kart42]

It has taken awhile but I feel I am starting to know how to burn coal in the Tarm 502. I am two days from having a continuous fire for a month. I guess I have "good" coal, because I have no problem with jammed grates, although I have developed a technique that is probably helping with that. A friend had a new coal stove of some kind, and noted that the grates were not moveable. The ashes were moved through them by moving a poker around in the bottom of the coal bed. The Tarm came with a long rod with a handle and so I have been poking that through the slots in the front swing gate all the way to the back of the chamber. Do this a number of times and some ash falls through, but it also helps to break up the "slag" and the shaker grates then work much better. I "shake and feed" twice a day. Generate a "hod" full of ashes a day and the oil burner hasn't even thought of turning on in 4 weeks. The "coal baffle" is , I now know, essential to successful coal burning. I had a few weeks of frustration while I learned (and unlearned most of my wood burning techniques) but it is going very well now. Only drawback is that I do need to be in the cellar twice a day, but that is to be expected. I am also not saving as much money as I had anticipated, since I decided to burn coal this year when oil was $4.50 / gal. However, I burned wood for 18 years and the price of oil stayed low until I quit. I still have the satisfaction of knowing the Arabs are not getting even $45/ barrel from me.

 

[glhenry56]

I guess this topic has gone cold (pun intended), but for anyone searching for info on Tarms and coal burning, I have an update on a "hot" topic (search "Tarm 404 - Question about coal baffles for burning anthracite" to find it).

The "official" Tarm coal baffles are very expensive (still available at Tarm USA in NH), but they have made burning rocks much easier than I previously experienced.

 

[cokehead]

I'm still out here. I took my oil burner out (It's in the back yard.) about 6 weeks ago. I'm heating my hot water with a mini coal boiler hooked up to a 77 gallon Peerless indirect water heater and heating the house with a coal stove upstairs. When I piped it up ( Montgomery Ward No. 20) I put in tees so I can pipe the Tarm to the same indirect for the heating system and use the tiny coal boiler for the summer. I have most everything I need to finish but the time. Don't hold your breath. I'm a bit slow. Maybe I'll have my first fire in the Tarm in a year or two. If I got by but in gear I could have it done in a coupe days.

 

[Jersey Devil]

Jonathan,

I have one. We have burned coal but went back to wood due to cost and ease of disposing of wood ash. Be sure to replace the DHW coil gasket before you fill it up.

Mike