Tarm Solo fan adjustments

[garysec]

Hi, searched the site for what I was looking for but could not pin down the answer. I have been burning without storage 24/7 during the winter months for 5 years, love my Tarm but suddenly yesterday started getting puff backs, smoke would not clear from the fire box and no good gasification in the secondary. Blamed it on being 5 weeks since being cleaned and sudden warm temperatures. Did a good cleaning, tubes, stove pipe, ashes in lower and restarted. Still not good, no gasification, real weak flame, no flue temp, opened tamper let fan run and still wasn't clearing smoke from fire box.
Noticed fan didn't sound like it normally does. Took off top shield and what they show in my manual as 'B' (fan damper I am guessing) started banging like it was stuck. I cleaned the fan, played around with 'A' which I have never touched, moved 'B' back and forth and it seemed to loosen it up. Turned it on and starting burning again more like normal, fan sounded better, but I would like to understand how I should set (A and B) because the manual does not help at all.
Any suggestions or explanations would be greatly appreciated.
Gary, Northeast Kingdom of VT.

 

[flyingcow]

My only suggestion is to call Tarm. They should be able to help you.

 

[jebatty]

My Tarm Solo Plus 40 has been in operation since the winter of 2007-08. It has been and remains a fantastic boiler.

As to A and B: A is the locknut assembly which sets the stop for the fan damper, and B is the damper itself. No adjustment of B, as its opening position is determined by the A locknut. If the fan itself is operating properly and the damper freely moves on its pin hinge (opens to the stop when the fan is on and falls against the fan housing when the fan is off), then I adjust A to limit air into the boiler if flue temps are too high and the boiler otherwise is clean.

Make sure the airway from the damper into the firebox (primary air) is clean and not plugged with creosote, and make sure the airway into the secondary gasification chamber similarly is clear. Brush the firetubes. Clean, but too well, the fly ash that collects in the lower chamber. A coating of fly ash on the refractory is OK. Make sure no buildup in your flue. Clean the smoke chamber on top of the firetubes.

If you have very dry wood and/or very small splits, both of which result in an especially hot fire, or other conditions which result in a very hot fire, you may have to adjust A to limit draft fan air into the firebox. Trial and error here. I burn very dry pine, I have homemade turbulators installed, and I need to adjust A anyway to limit air. I probably have it closed down to limit the damper opening to about 1/2 of full open. Flue temp tells me then if I need to open or close more. I aim for maximum flue temp less than 500F, more typically 380-450F. Because my wood is dried at least two full summers, I rarely have to change the A setting, as my wood is quite consistently of the same dryness and split sizes.

As you note regarding sudden warm temperatures, draft through the boiler diminishes with higher outside temperatures, and vice versa. Warm temperatures decrease draft and can contribute to the problem you mention, as can particular wind conditions. In fact, during the early and late heating seasons when outside temps are warmer, I may adjust A to allow more air into the Tarm if I'm not getting a good burn/gasification.

 

[garysec]

Thanks Jim, a much better explanation then the manual provides. Think maybe 'B' was not moving freely just due to dust etc. and never being cleaned, and possible the weather. My 'A' adjustment knob has always been all the way out so 100% open and I have a good heated interior chimney that drafts well and for the most part have good seasoned hardwood and small splits. That is probably why my flu temps have always been around 600+ and figure when I am pushing 700 it is time for a cleaning. I do check the 2 holes in my firebox above the door to make sure they are clear from creosote but guess I will need to look to find the airway into secondary to check but think it must be pretty good because I have gotten my good roar back I like to hear. I have never taken off the plate between the 2 doors either to clean which I need to plan to do. I normally try to do a good full clean, brush, and vacuum of boiler, tubes and stove pipe every month during the heating season. Thanks again, Gary

 

[rcollman]

Not saying why I suggest this, but check for ash build up anywhere in the horizontal flue pipe before it goes vertical. Also check for ash buildup and pull ash from the very back of the boiler under the tubes to the cleanout door.

I am willing to share my sins but will stick with the solution, until someone wants to know how I know I liked the explaination of the A and B and will look closely at mine and put that on my checklist.

 

[Thom Griffin]

As long as you're doing all this adjusting, you might want to take the fan out and give it a really good cleaning. It drastically changes the output when the squirrel cage gets a thick coating of dust/ash/whatever. No need to be obsessive about it; I've only cleaned it once in 3 or 4 years, but it did make a difference.

 

[garysec]

rcollman, I must admit that I had more ash in there than I have every had, usually I clean my tubes first but when I ran my brush down the first one I felt a little resistance and then realized I had not down a very good job of late cleaning horizontal on a regular basis so pulled all that out first.
I started to play a little with fan adjustment last night but even if I turned 'A' all the way in I don't think 'B' would ever hit it so turned it back. Guess I will need to take the fan off so I can see how that damper is set up. I don't see where adjusting 'A' as it is will do anything.

 

[jebatty]

"A" is a bolt with a locknut that determines how far the "B" damper travels between open and closed: open when the fan is on because the fan pushes the damper open and closed when the fan is off because the damper pivots to a down/closed position. Natural draft through the boiler with the fan off can result in the damper being pushed open to some extent. Loosen the locknut, adjust the bolt travel, and refix the locknut.

 

[KenLockett]

Not saying why I suggest this, but check for ash build up anywhere in the horizontal flue pipe before it goes vertical. Also check for ash buildup and pull ash from the very back of the boiler under the tubes to the cleanout door.

I am willing to share my sins but will stick with the solution, until someone wants to know how I know I liked the explaination of the A and B and will look closely at mine and put that on my checklist.

In my third season with my Solo Plus 40 and I usually clean the ash in the horizontal flue at the end of the season. Have that buildup in the rear and just under the tubes and do my best to get it out but usually can't get all of it. By the way, by the end of the season there is a substantial amount of ash in the horizontal section of the flue. Have contemplated taking the flue apart mid-season to clean the ash but hate taking it apart as I have to re-silicone the joints. What exactly do you mean by share my sins? Just curious.

 

[KenLockett]

Thanks Jim, a much better explanation then the manual provides. Think maybe 'B' was not moving freely just due to dust etc. and never being cleaned, and possible the weather. My 'A' adjustment knob has always been all the way out so 100% open and I have a good heated interior chimney that drafts well and for the most part have good seasoned hardwood and small splits. That is probably why my flu temps have always been around 600+ and figure when I am pushing 700 it is time for a cleaning. I do check the 2 holes in my firebox above the door to make sure they are clear from creosote but guess I will need to look to find the airway into secondary to check but think it must be pretty good because I have gotten my good roar back I like to hear. I have never taken off the plate between the 2 doors either to clean which I need to plan to do. I normally try to do a good full clean, brush, and vacuum of boiler, tubes and stove pipe every month during the heating season. Thanks again, Gary

In my third season of operation with the Tarm Solo 40. First two seasons used mechanical probe type gauge provided with boiler and regularly saw flue temps in 600 - 800 range. Like you cleaned when temps reached 750 - 800 on regular basis (around 4 weeks between cleanings). This season I actually bought a type K thermocouple and have run it back to temperature controller and PLC based monitoring system I put together. What I have realized is that the mechanical gauge is highly inaccurate. My flue temps when running with the chain turbulators Jim (JE Batty) recommended i now see temps between 350 - 500. Attached below is a trend of the flue temps beginning with my last cleaning on 12/4 and the cleaning I just did last night (36 days). The signals are not noisy as they appear. What you are seeing in the trend are the idle/fire cycles Notice that the temps start out around 350-400 and I finally start seeing temps on a regular basis above 500 and actually saw a 581 day before last signaling time to clean. In addition, wanted to show off the tool I fabricated to clean the boiler tubes (based upon a post I saw on the forum). This tool takes any crud off the tubes like they were butter. It is on a 3' threaded rod and I used my wireless drill to clean tubes with. Steel gauge heavy enough that it pretty much retains shape but I simply stretch the sides a bit if I want to be more aggressive in the tube.

 

[KenLockett]

With the warmer temperature today, just generated a new alarm in my PLC based monitoring system alerting me when an idle cycle exceeds 90 minutes. typically, my idle cycles are in the 20-60 minute range depending on heating load and outside temperature. When the alarm comes in, I simply bump my thermostat up a degree or so. Essentially transferring stored heat energy from boiler to house thus reducing idling period. I must have too much time on my hands!

 

[KenLockett]

By the way, after a fresh cleaning, firing cycle times vary between 8-12 minutes (depending upon heating load and ambient of course). When boiler tubes are dirty and coated with ash, firing cycle times increase to 20-30 minutes or more. For us analytic types, data is so insightful. My wife just stares at me blankly when I get excited about these things,