Gasser function differences?

[711mhw]

I would like to know the operating difference of the wide variety of units that are represented here by all of us. Earlier this fall I had a chance to meet Mark? (name?) I think from AHoNH? at the Freyburg Fair in ME. Very nice guy, and I had a bunch of questions for him, but because I was not going to be a customer (already had my wood Gun) and he was loaded with potential customers there, so I stood down. In our little bit of conversation that we did get in, he was talking about o2 sensors and different fans and in general, a ton of gismos that are not in my WG. Rembering reading somewhere (here) a comment that you could fix a WG with bailing wire and duct tape, (I'll second that) it makes me wonder the following; (of all brands)
What are some of these controls
What is the benefit
If efficiency, how much
What are the potential probs. if that fails
Is it a "must have storage" unit
Really not wanting to get into what's the better unit (Ford vs. Chevy) type discussion, just more factual type stuff and please not to technical. This is a curosity and learning thing for me and I think it might help some new folks on here with their decision making. I stumbled across the WG guys crusing around on the computer one night and thought that they invented the gassifaction thing! I had never heard of it. THey were close to where I used to live so I checked them out in person one day, I was impressed- sign me up! Totally my ignorance of burning wood, but luckey me, I am very satisfied, but maybe with some more facts and knowledge I would have made a different choice? Please feel free to add relevant questions to mine.
In shorter words, I only know my WG tell me about yours.

 

[Hunderliggur]

I bought my Paxo 40 from Mark at AHONA, along with 2 refurbished 500 gallon tanks, stacking fixture, in tank heat exchanger, and two temperature controllers. I am satisfied with what I have. The controller is basically the same as the Eko controller (they are both built by Olan) and I think similar to others. It is basically a differential controller with timer functions and adjustable fan speed control. No offense to mark, but the controller probably could be better but what I have works. The FUEL out shutoff is unreliable, and I don't know an answer (using the supplied controller) on how to stop the circulator when the fire is out but the storage temp is about the circulator launch temp. I have ordered two $30 after market kiln controls to shut off the fans and circulator when the fire is out (based on stack temp) and turn on the circulator when the boiler temp is above limit (200F). As far as replacing the controller, it would be fairly straight forward to make a differential replacement if you could not net a replacement controller. The only moving parts are the fans and the circulator (both outside the boiler unit), a there is boiler temp sensor on the top of the unit. The cotrol logic for "puffing" the fans when idling would take some work but it can be done.

 

[711mhw]

Thanks Hunderligger! In reading your response, I realized that most of you guys are prolly as unfamilar with the WG as I am with the others! The only controls that I have - make that contol not (s) is a aquastat, period. It turns the fan on and opend the intake air door, and does the reverse when it's (aquastat) satisfied. WG directions: put wood in, turn on power, light match, close door. Repeat put wood in part when necessary. What does your controller monitor?
Another question that I have is there an "official" deffinition for idling? As far as I know, my WG is starved of intake air and the fire is as close to "out" as it can be. Are others more true to the term idling as in keeping a small fire?
I would like to have an "out of fuel" automatic turn off like your's has to keep cold air from breing pumped thru my fire box. (I have a outside air intake) I am also thinking that storage would be nice for the "shoulder seasons" , it can get pretty hot in the house when it warms up during the day, but it keeps the "old lady" 'bout half nekked so theres a plus.

 

[Fred61]

If you do not have a second aquastat installed, get one and set it to the boiler temperature you want the fan to stop. Have it activate a relay that breaks the power to the fan.
Now this design is more complicated than it sounds in the above statement but a competent circuit designer can make it work. I built one with the help of a friend but I must have thrown the schematic away.

 

[711mhw]

Got that, just didn't mention it because it's not a part of the (regular) operation of the boiler and I assume that all boilers have or are required to have this overheat shutdown function. Thanks
Fred, you should be speaking out here. I know that you are on your second boiler, sorry about your first go round. But ya got 2 wood boilers under your belt and surely can understand my question. You must have thought that you were looking under the hood of the space shuttle (of your new unit) after having your WG. Aside from your premature failure ( I'm not a metalurgist, can't even spell one but it may have been just a flaw in the sheet of steel) does your current WB have a lot of controls and do you think that it saves on wood or has an advantege? Thanks again!

 

[Singed Eyebrows]

I would like to know the operating difference of the wide variety of units that are represented here by all of us. Earlier this fall I had a chance to meet Mark? (name?) I think from AHoNH? at the Freyburg Fair in ME. Very nice guy, and I had a bunch of questions for him, but because I was not going to be a customer (already had my wood Gun) and he was loaded with potential customers there, so I stood down. In our little bit of conversation that we did get in, he was talking about o2 sensors and different fans and in general, a ton of gismos that are not in my WG. Rembering reading somewhere (here) a comment that you could fix a WG with bailing wire and duct tape, (I'll second that) it makes me wonder the following; (of all brands)
What are some of these controls
What is the benefit
If efficiency, how much
What are the potential probs. if that fails
Is it a "must have storage" unit

The Lambda boilers have a computor/PLC to operate the servo motors/flaps & the 02 sensor is one of the inputs. I believe the one from Ohona has one servo for both primary & secondary./ The benefit is being able to throw the wood in & just walk away letting the PLC adjust the air. The German Lambda Biturbo Kunzel(not in the USA) will burn kiln dried cabinet scraps, something my Atmos would go into meltdown with. I know the Froling controller is around $1000, never ever heard of one failing though. The Austrian KWB has a boiler that is right around 94 percent & this is condensing some as a moisture tight chimney is required. You won't burn with accurate low flue gas temps without computor control. My Atmos is a simple boiler with an induction fan that has it's inlet controlled by a Samson flap. This works well although untill the flap is down you need to keep an eye on it, Randy, I believe the German & Austrian lambda's will eventually get here, Froling already is.

 

[Fred61]

Got that, just didn't mention it because it's not a part of the (regular) operation of the boiler and I assume that all boilers have or are required to have this overheat shutdown function. Thanks
Fred, you should be speaking out here. I know that you are on your second boiler, sorry about your first go round. But ya got 2 wood boilers under your belt and surely can understand my question. You must have thought that you were looking under the hood of the space shuttle (of your new unit) after having your WG. Aside from your premature failure ( I'm not a metalurgist, can't even spell one but it may have been just a flaw in the sheet of steel) does your current WB have a lot of controls and do you think that it saves on wood or has an advantege? Thanks again!

Actually I wasn't talking about overheat protection. I thought you were asking about shutting off the combustion fan when the fire was out. I was thinking about a second aquastat to activate on temp drop to stop the fan from running and continuously cooling the boiler.

I've got to go now but I'll address your other question tomorrow.

 

[infinitymike]

I'd like to chime in.

I have a Wood Gun E100.

I will be starting the final piping on tuesday and should be ready to burn wed/thurs the latest.

AHS offers at the time of purchase a low-temp shut off control.
Which I, not being informed enough, did not purchase.

After reading alot more threads since my purchase I realized I should have bought it .

I called them and they said the could sell me the controller and I could wire it up.
They want around $250+/-

Could I do it cheaper like you did Fred?

The same goes for a cycle timer. Another $250 that I could spend (unless there is a cheaper way) Which is for heating DHW in the summer and possibly for the shoulder seasons when the heat loads are not too frequent.

What it does is cycle on the unit by turning on the draft fan and opening the air valve every couple of hours for 10 minutes or so to keep the unit up to temp so when the demand for heat is needed the unit will fire up.

Remember a WG "shuts off" by cutting off all oxygen to the fire box. and "turns on" or re-lights the wood by the introduction of O2 to a hot refractory.

So if the refractory is cold because the fire has been "off" for a while because there has been no demand for heat it won't re-light.

I say all this with ABSOLUTELY NO experience. Just what I was told from the guys at AHS.

What should I do? Bite the bullet and drop $500 or find a way to do it on my own with some aqua stats/relays and timers. None of which I have the intelligence/experience to design on my own.

 

[bpirger]

The Garn's have integrated storage, the firebox sits inside a 1500, 2000, or 3200 gallon water tank. With the latest controller, you push the button, which turns on the fan. The controller runs the fan for 10 or 15 minutes (I forget which), when you are supposed to be getting your fire going. After this 10 or 15 minutes, the controller starts comparing the flue temp (a sensor in the HX) with the water temp...and when it is within a couple of degrees, the fire is out...so the fan is shut off. For the Garn, that's it. You always burn flat out, each and every time, dumping everything into your integral storage. Everything is quite simple, quite rugged. Storage is an open system, so you want to monitor your water chemistry and remain isolated (through a HX) with your distribution system most likely. That is the down side of the Garn. And the price....the 1500 will have you sending out about $13K, for the boiler setup alone. But your storage is done, it is simple to connect, never have to worry about idling, bridging, etc. Monitor your water chemistry (inlcuded for life) and pay the upfront cost.
Efficiency is supposed to be in the low to mid 80's....I haven't yet measured myself...though Jim has some great reviews on the 3200...

 

[rkusek]

I'd like to chime in.

I have a Wood Gun E100.

I will be starting the final piping on tuesday and should be ready to burn wed/thurs the latest.

AHS offers at the time of purchase a low-temp shut off control.
Which I, not being informed enough, did not purchase.

After reading alot more threads since my purchase I realized I should have bought it .

I called them and they said the could sell me the controller and I could wire it up.
They want around $250+/-

Could I do it cheaper like you did Fred?

The same goes for a cycle timer. Another $250 that I could spend (unless there is a cheaper way) Which is for heating DHW in the summer and possibly for the shoulder seasons when the heat loads are not too frequent.

What it does is cycle on the unit by turning on the draft fan and opening the air valve every couple of hours for 10 minutes or so to keep the unit up to temp so when the demand for heat is needed the unit will fire up.

Remember a WG "shuts off" by cutting off all oxygen to the fire box. and "turns on" or re-lights the wood by the introduction of O2 to a hot refractory.

So if the refractory is cold because the fire has been "off" for a while because there has been no demand for heat it won't re-light.

I say all this with ABSOLUTELY NO experience. Just what I was told from the guys at AHS.

What should I do? Bite the bullet and drop $500 or find a way to do it on my own with some aqua stats/relays and timers. None of which I have the intelligence/experience to design on my own.

$500 sounds like a lot for that, I think you could buy the parts for less than a $100. An EKO controller sells for $200 (and that's marked up). I would consider that if I owned a Wood Gun before spending $500 because I believe the variable speed would still work with your fans (Not 100% sure though) and it would keep the coals stoked during idle with the short bursts. I will have to check my settings but sitting next to it last winter when it was in idle I though it gave about a 5 second burst of fan every 10-15 minutes. Much more often than what someone else was saying with the mechanical timer but I guess the effect would be the same.

All that said I bet your best bet would be to spend the $30 like Hunderliggur did and get a 2 stack probe meters with the digital readout and the relay outputs. Add a couple $5 relays and a maybe a 10 minute timer between that and the fan power source. So after the stack temp drops below a certain temp for 10 minutes WHILE THE FAN IS ALSO RUNNING we could assume the wood supply is gone. That would solve the FUEL out issue. Mechanical duty cycle timers are out there, you would just have to find one that would work. A quick Google search led me to this on Ebay (2 for $75) and they appear to be good quality. That could be used to "stoke" your coals for a set period of time after the timer has count down the setting of your idle time (say 20 minutes). The RESET terminal would connect to your existing fan control so if your fan came on normally the 20 minutes would reset. As far as aquastats go, I have a Johnson Controls A419 aquastat that goes for about $65 recommended by someone on this site that works well too. The mechanical Honeywells do the job as well but this one has a digital display and allows you the change the setpoints and thresholds a little easier. I'm just throwing out ideas, maybe someone with a Wood Gun can give out specifics if these things sound unfamiliar. It's good to learn all you can about your system and understand how it works so you can maintain it yourself. I think for many of us here wood burning is a hobby with some added benefits. I could never justify keeping a warm workshop all winter if I had to buy fossil fuel and mine is well isulated. JEBEATTY on this forum has a Tarm but is helping a nonprofit group with that heats a large building with both a Garn and a Wood Gun. It would be great to read up all his posts and see how he has that Wood Gun set up to handle the issues you have mentioned. He has done some neat stuff using temp sensors, controls, and measuring efficiencies.

 

[jebatty]

The fun never ceases. My experience is limited to a Tarm Solo 40 (my own), now in its 5th heating season; a Wood Gun E500 and a Garn WHW3200, both now in their 3rd heating season. The WG and Garn are installed at Deep Portage. Given what I've done, I can support simplicity and I also can support some key add-ons, or upgrades if available from the mfr.

As to the Tarm, the controller shuts the draft off when the fire is out, adjusted by its own thermostat, and it shuts the Tarm down completely on overheat. Simple and effective. I also have added 1000 gal pressurized storage. My only changes are wiring the controller to also shut off the circulator when the fire is out, and a stack overheat controller that shuts the draft fan off it the stack temp gets too high. Plus I monitor key system points and data logging as needed, both of which have greatly helped me to understand how the Tarm functions. Since I started weighed wood burns last year and learned that I now can always load the Tarm so that it burns full out and never idles, I am continuing weighed wood burns. Storage makes this possible, along with a couple of sensors and digital panel meters to monitor the storage tank. I have not had any repairs, wear-outs, replacements of any kind with the Tarm.

As to the WG, I know that the mfr says storage is not needed and letting the WG cycle is fine, but I also know that since DP added 4000 gallons of pressurized storage, WG operation has become a breeze and nothing could be simpler. The WG now always takes a full load of wood (100 lbs+) and then walk away. It no longer ever cycles. In this respect it operates much like the Garn, the primary differences being that the WG is kicking out 160F+ water nearly from the start -- no need to first heat the tank before hot water is delivered to the system -- and that the WG is designed to continuously put out high temperature water, 180F+ or so. The only add-on required for the WG was a motorized boiler return water protection valve, as I think all wood boilers require. Due to installer errors or ignorance, this was not installed or controlled correctly, but that now has been solved through re-plumbing, adding a 2nd sensor and reprogramming the Tekmar controller. What would be very beneficial for the WG is a draft fan and circulator shut down when the wood load has burned out. I'm waiting for the go-ahead from DP to add this, which must be done by or approved by an electrician. There have been no operational or mechanical problems with the WG, other than the mechanical timer failing, which DP did not replace.

As to the Garn, it functions with simplicity: throw in a full load of wood (100+ lbs) and walk away. What also would be very beneficial for the Garn is a draft fan and circulator shut off when the wood load has burned out. DP is following up with the mfr on this. Keeping the draft fan operating (now a mechanical timer) when the wood load has burned out continuously moves lots of air through the Garn tank, and I can't help but believe that this throws lots of stored btu's up the stack. Of course, the Garn does not deliver hot water immediately because it needs to heat 3200 gallons of water first. Garn also has advised that efficiency declines in applications where water temp greater than 140F is needed. There have been no operational problems with the Garn, but the draft fan motor has failed 3 times, I believe, and Garn now is providing a different motor than the one that was originally supplied. This new motor was just installed last week. Hopefully this motor will be more dependable.

I would think that lambda or other more sophisticated controllers, including variable speed draft fan, would result in all 3 of these boilers operating more efficiently. But with sufficient storage and the ability to always burn a full load of wood without idling or cycling, I tend to think that all 3 of these boilers are operating at their design best. It would be interesting to see some data on the efficiency gain provided by more sophisticated controllers vs how these 3 operate now.

 

[Fred61]

Got that, just didn't mention it because it's not a part of the (regular) operation of the boiler and I assume that all boilers have or are required to have this overheat shutdown function. Thanks
Fred, you should be speaking out here. I know that you are on your second boiler, sorry about your first go round. But ya got 2 wood boilers under your belt and surely can understand my question. You must have thought that you were looking under the hood of the space shuttle (of your new unit) after having your WG. Aside from your premature failure ( I'm not a metalurgist, can't even spell one but it may have been just a flaw in the sheet of steel) does your current WB have a lot of controls and do you think that it saves on wood or has an advantege? Thanks again!

The EKO in my opinion is simpler than the Wood Gun. More like a conventional boiler with a damper that shuts tight and diverts the burning gasses down. The LED controller could impress you for a few seconds but it's only a tool. It doesn't have the lamda controls that are being installed on the more current boilers. I have mixed feelings about whether it's worth fine tuning our fires to that extent. My EKO burns pretty clean and efficiently. The tin work and insulation is better on the EKO.

There weren't many choices when I bought my Wood Gun and it had a short life with alot of problems but I was still convinced that if you were going to burn wood, gassification was the way to do it, however I didn't feel it was worth it because they eat themselves up. After several years of using a wood stove and oil I sold my big place and purchased this little 1000 sf ranch and a big motor home. Having been a tinkerer and a pretty good carpenter and alot of time on my hands as well as a hyperactive mind, I had myself a hobby. I tore into walls, roofs, garages,and everything else you can think of. If you want to modify a house, a ranch is the thing to have. Anyway, one day I decided to put in radiant heat. Hey, lets heat it with wood! Remembering that the only way to heat with wood is gassification' I started looking. I know I didn't want a Wood Gun so I went over and visited Mark at AHONA. He showed me the Biomass and the EKO and all the time I was there I was asking more or less the same question to alleviate my fears which was "is it going to eat itself up like the Wood Gun?" So that's how I got to this point.

In reading other posts, I see that AHS is offering the low temperature shutdown add on for $250.00. In my opinion It's not worth it to build your own for that price. By the time you buy the components which in mine consisted of two momentary on switches one dpdt toggle, one time delay relay, one dpdt relay, lots of wire, indicator light and housing plus the labor and time spent refining it you could just buy it. And you should. It doesn't take much time to cool down your boiler when running outside air through it at the rate a Wood Gun moves air.

For the cycle timer, I would try to make my own. Something you could do on your own time. It's not that important and you could live without it unless if your home looses heat so fast, you will get up in the morning with a frozen house. Most people with woodstoves experience that every day. Don't forget, it's not going to fail to re-light every time, only occasionally. It should be pretty simple th toggle one up after you have slept on it for a while.

To answer your last question, no the controls don't save anything, just add convenience. In fact I disconnected the circulator controls and am using a Tekmar 156 which gives me more flexibility like differential temperature control between the EKO and storage leaving the control to control the boiler high temp set point and the low temp shut down as well as the on off switch.

 

[muncybob]

Fred, from what you know of the low temp shutoff option from AHS...will it work exclusively in "wood only" mode? I ask this since my boiler is wood/oil and I would not want the unit to shut down if it reached low temp point while in auto or oil mode as this is when I would want it to switch from wood to oil.
A low temp shut off would give me a bit more peace of mind and many nights I would not even bother to run the cycle timer since starting a new fire in the morning is no problem for me and by the time I have taken care of the animals I would have hot water & heat.

A statement Jim made about return temp protection has me concerned. How do I know if my valve is working properly?

 

[Fred61]

Fred, from what you know of the low temp shutoff option from AHS...will it work exclusively in "wood only" mode? I ask this since my boiler is wood/oil and I would not want the unit to shut down if it reached low temp point while in auto or oil mode as this is when I would want it to switch from wood to oil.
A low temp shut off would give me a bit more peace of mind and many nights I would not even bother to run the cycle timer since starting a new fire in the morning is no problem for me and by the time I have taken care of the animals I would have hot water & heat.

A statement Jim made about return temp protection has me concerned. How do I know if my valve is working properly?

Bob I only know that they offer it from posts here on the forum, maybe yours. Actually the one I built had the oil function in it. I think I posted this scenario before but here's the reason I had a need for it:

1 I load up the chamber with wood, get it going and either leave or retire for the night.
2 Boiler fails to re-light or runs out of wood and fan continues to run drawing in cold outside air until oil kicks in.
3 Oil burner fires and brings the boiler back up to temp. and shuts down.
4 The next time the boiler needs to be satisfied, the combustion fan starts and since there is no wood or it doesn't re-light it cools down until the oil brings it back up.
5 Over and over again. Not too efficient you might say!

My controller would lock the unit into "oil" mode until I was physically there to release it before starting the next fire. Th circuitry would be pretty much the same except mine shifted power to the oil burner instead of to the off position.

When I was around or not off too far and knew there wasn't a need to fire the oil, I just switched off the burner and the unit just functioned as a low temp. shutoff.

I would call AHS and ask them how it functions.

 

[taxidermist]

. .

The FUEL out shutoff is unreliable, and I don't know an answer (using the supplied controller) on how to stop the circulator when the fire is out but the storage temp is about the circulator launch temp. send me a pm as to what you dont get and maybe I can help you as mine works fine.

Rob

 

[willworkforwood]

A statement Jim made about return temp protection has me concerned. How do I know if my valve is working properly?

The most inexpensive option is to buy a "frothing" thermometer, or something similar - they're probably still around $5 on ebay. Tape (ASJ, h/t Duct, ...) the stem onto the pipe coming back into your boiler and wrap it with insulation. Make sure to "sync" the therm using ice or boiling water before installing it. The ones I'm using have a "red" zone highlighting 140-160, which makes it easy to spot any return temp issue, without needing to read the actual numbers. Others use IR guns to spot check temps, and there are also a bunch of previous threads describing fancier stuff using one-wire sensors and digital displays if you don't mind spending a few more $$. And, if you're interested in finding out exactly how the valve is working, buy a couple more for the feeder pipes into the valve, then sit back and watch the show ;-). I have 8 of them, checking various points in my system, and you can learn lots of things (and maybe make improvements) by watching the multiple temps.

 

[muncybob]

Thanks...a new project on the horizon.

 

[Fred61]

I just spent the last two hours searching for any information, in particular the schematic for my shut down circuit in hopes I could post it here to help you fellows out but I think I was so pissed off at the entire thing that everything went, including the paperwork. I now regret not salvaging the tankless coil, draft door actuator and controls.

 

[infinitymike]

I know I didn't want a Wood Gun "is it going to eat itself up like the Wood Gun?" So that's how I got to this point.

Fred what do you mean it ate itself up.

How long ago did you own it? How long did it last?
I bought a Stainless firebox maybe that will help.
Sorry to here your discontent with the WG.

 

[Fred61]

Fred, from what you know of the low temp shutoff option from AHS...will it work exclusively in "wood only" mode? I ask this since my boiler is wood/oil and I would not want the unit to shut down if it reached low temp point while in auto or oil mode as this is when I would want it to switch from wood to oil.
A low temp shut off would give me a bit more peace of mind and many nights I would not even bother to run the cycle timer since starting a new fire in the morning is no problem for me and by the time I have taken care of the animals I would have hot water & heat.

A statement Jim made about return temp protection has me concerned. How do I know if my valve is working properly?

Bob, could you look up the wiring diagram for your unit and either post it here or PM me with it displayed. If I study it for a while I may be able to figure out what I did to modify it.
No promises, I was 30 years younger then.

 

[muncybob]

Sure Fred, but don't do this on my behalf as I have to call AHS anyways and I'll ask them my questions. I'll try to remember to do this tomorrow.

 

[Fred61]

Sure Fred, but don't do this on my behalf as I have to call AHS anyways and I'll ask them my questions. I'll try to remember to do this tomorrow.

Well actually I was thinking if I could come up with a design, we could do a materials list to see what the cost would be on a do it yourself unit.

 

[711mhw]

Got that, just didn't mention it because it's not a part of the (regular) operation of the boiler and I assume that all boilers have or are required to have this overheat shutdown function. Thanks
Fred, you should be speaking out here. I know that you are on your second boiler, sorry about your first go round. But ya got 2 wood boilers under your belt and surely can understand my question. You must have thought that you were looking under the hood of the space shuttle (of your new unit) after having your WG. Aside from your premature failure ( I'm not a metalurgist, can't even spell one but it may have been just a flaw in the sheet of steel) does your current WB have a lot of controls and do you think that it saves on wood or has an advantege? Thanks again!

Actually I wasn't talking about overheat protection. I thought you were asking about shutting off the combustion fan when the fire was out. I was thinking about a second aquastat to activate on temp drop to stop the fan from running and continuously cooling the boiler.

I've got to go now but I'll address your other question tomorrow.

Ok I misunderstood you. I'm not an electronic control wiring type of guy so here's a question, can more than one function be controled from a typ. aquastat? And seeing that my boiler does not have extra "tappings" to add another one, is an aquastat available that will control several different motors/fans and that can have more than one temp.setting?
This has turned into a real nice discussion, thanks to all. And Mr.Fred, do you feel that your WG failure was caused by it's operation/design or something else? I did not get the SS upgrade and it was suggested that if I were not running it all summer for DHW that I'd be fine with carbon steel, but to keep it hot, run it at 200deg. My thinking was that if I got 10 or more years out of it, I'd be of the age where my wood chopping was no longer fun and go with something else. (my thoughts were a "Coal Gun")
One last question, why are the Garns unpressurised? I'v not had to juggle with the water chemistry and it may be a simple thing to do, but I do remember Rick's (name?) post and his cleaning nightmare with his (where is he?) Garn.

 

[Gasifier]

Hey 711. On your Wood Gun you should of had two Aquastats already on it. One for high limit, on the top of the Wood Gun. And one for operating limit, on the back of the Wood Gun(right side if you are looking at the back). On the left side, if you are looking at the back is another place you could put an Aquastat(same level). That is what my guys did. That Aquastat controls my circulation pump, and as Fred said, you could use it to control your fan if you wanted that to shut down at the same time. I think that is what Fred was saying. Hope that helps.

 

[Fred61]

Got that, just didn't mention it because it's not a part of the (regular) operation of the boiler and I assume that all boilers have or are required to have this overheat shutdown function. Thanks
Fred, you should be speaking out here. I know that you are on your second boiler, sorry about your first go round. But ya got 2 wood boilers under your belt and surely can understand my question. You must have thought that you were looking under the hood of the space shuttle (of your new unit) after having your WG. Aside from your premature failure ( I'm not a metalurgist, can't even spell one but it may have been just a flaw in the sheet of steel) does your current WB have a lot of controls and do you think that it saves on wood or has an advantege? Thanks again!

Actually I wasn't talking about overheat protection. I thought you were asking about shutting off the combustion fan when the fire was out. I was thinking about a second aquastat to activate on temp drop to stop the fan from running and continuously cooling the boiler.

I've got to go now but I'll address your other question tomorrow.

Ok I misunderstood you. I'm not an electronic control wiring type of guy so here's a question, can more than one function be controled from a typ. aquastat? And seeing that my boiler does not have extra "tappings" to add another one, is an aquastat available that will control several different motors/fans and that can have more than one temp.setting?
This has turned into a real nice discussion, thanks to all. And Mr.Fred, do you feel that your WG failure was caused by it's operation/design or something else? I did not get the SS upgrade and it was suggested that if I were not running it all summer for DHW that I'd be fine with carbon steel, but to keep it hot, run it at 200deg. My thinking was that if I got 10 or more years out of it, I'd be of the age where my wood chopping was no longer fun and go with something else. (my thoughts were a "Coal Gun")
One last question, why are the Garn unpressurised? I'v not had to juggle with the water chemistry and it may be a simple thing to do, but I do remember Rick's (name?) post and his cleaning nightmare with his (where is he?) Garn.

Did you get the oil burner add on. I don't know about the 100 but the 140 had a second aquastat on the back just to the left of the wood aquastat. If you don't have oil there should be a tapping for another well.

I have the sensor for my Tekmar 156 hugging the hot output pipe just at the outlet of the vessel and it works pretty good. close enough anyway.

do you have your boiler within the confines of your home or in a shed? If it's in your home you won't want to run it in the summer. They don't have the best insulation.

I think your firebox walls will corrode less if you add storage which will allow hotter, longer fires. Yes, having the vessel full of pinholes was something I fought for the last two years and periodically had a welder come in and apply patches but what I was fighting for most of the years I burned it was wear on the refractory, center bricks, door refractory and burned out door gaskets.
I think the air moves so fast that it causes erosion of the interior of the unit i.e. sandblasting with ash as the media. The other is the doors are used as targets for the hot blast and it puts a terrible heat load on the gaskets. The gaskets are on the same plain as the refractory target unlike the Eko which has the interior of the door extended into the heat which creates a labyrinth to protect the gaskets.