TARM SOLO 40 Plus MKII WATER STORAGE

[Patti]

Hi All!
I’ve been following this site for a number of years, and learn something every time I read posts. . I appreciate the advice and answers that are offered by so many experienced people!
I have the Tarm model mentioned above, and this will be the third winter using it.
First winter: had a 600 gallon water storage tank, but didn’t stand up to the pressure, so not hooked up. (Not happy about that). Burned a fair amount of wood.
Second winter: Modifications made (not by me!), but couldn’t get it airtight, so not hooked up-
(again). 😠 (really not happy about that).
Third Winter (this year): 1000 gallon tank ‘in the process of being installed’…. so not hooked up yet. (REALLY REALLY not happy about that
😠😠)

Now… my friend who is doing this installation and I are having heated ‘discussions’ about the whole ‘water storage’ thing, so I’d like to hear people’s opinion.

I have explained (many times) that running this model (don’t know about others - I’m just speaking about this Tarm) without water storage is NOT GOOD.
•I’ve told him that Tarm would NOT honour warranties on their boilers if they were operated without water storage.
(that should be SOME indication of the IMPORTANCE of water storage! 🤷‍♀️)
•I have explained that without the water storage,
a) you burn far more wood
b) it needs to be stoked every 4 -5 hours (not fun trekking out to the shop in the middle of the night😒)
c) Constantly shutting down, idling, and reigniting not only causes more creosote, but more importantly- it is HARD on the boiler’s components. This will mean costly repairs and will shorten the lifespan of the boiler considerably.

However…my friend absolutely refuses to take my word for it that this Tarm gasifier NEEDS to have WATER STORAGE.
(He is a plumber (& had his HVAC ticket) and has installed outdoor boiler systems before.
He also knows someone with the same model Tarm I have, with NO storage.
BUT…it is inside their heated garage attached to the house that has radiant heating.
Whereas mine comes 110’ from my shop to my house and goes through a heat exchanger to supply forced air heat (to a 160 year old log cabin..that needs new windows but is otherwise fairly energy efficient).

So because this other guy doesn’t have a storage tank, my friend is adamant that it ‘won’t do any harm to the boiler’ to run it without water storage.
I have had to (very unwillingly) use it for the last two winters without the water storage.
He says I should just be ‘starting the boiler’…but I am putting my foot down and WON’T start the boiler until the water storage is there (and in the meantime, HE can pay the $750 a month it costs for propane (& that’s with the thermostat at 65°)

SO….I need some back-up from experienced Tarm owners 😊
He’s telling me I’m wrong, and shouldn’t be concerned about it- water storage is just a ‘recommendation’. 🙄
I, on the other hand, totally disagree, 🤦‍♀️ so this is causing some battles! 😣

SO…Can anyone provide me with detailed information about how the boiler is affected overall, and what specifically may be damaged/need replacement.
Can other people confirm that storage is NOT just a ‘recommendation’ but is a NECESSITY for Tarm gasifiers, to enable the system to operate efficiently AND not sustain damage (well, any MORE damage than has already possibly occurred.🙄)
Perhaps if he hears it from experienced Tarm owners it will be enough to convince him…and he’ll believe what I am saying

And if I’m wrong, you are welcome to tell me that too! 😊 I don’t profess to know everything about these boilers …but after reading and researching this model for a few years, I do think I know what I’m talking about when it comes to the water storage issue! 🤷‍♀️😁)

Thanks for any input!
(and for helping to stop World War 3 from happening! 🤣)
Patti

 

[peakbagger]

You have ticked off most of the reasons why folks use storage. Normally a boiler is installed inside the conditioned space (or adjacent to it like in a basement) so that heat loss from the boiler or the storage is not wasted. As for structural damage to the boiler I am not sure how much is done by operation without storage. Creosote can be acidic and when it builds up thickly, it can be more agressive at attacking steel so this type of operation will need to be cleaned far more often or the boiler could rot out. I say "could" as Tarm's in general were pretty robust units and my guess is they were overbuilt so that fireside corrosion is less of an issue.

I am not familiar with the newer Tarm designs on how they control boiler over temperature conditions, the older ones had a air damper that closed when the amount of heat being produced by the boiler exceeded the amount of heat being asked for from the house via the thermostats. Some systems have heat dumps so if the demand doesnt match supply they just dump heat to dump zone.

I am assuming that the installation is equipped with a thermovar valve (broken link removed to https://store.tarmusa.com/collections/thermostatic-valves) that minimizes low temperature operation during startup?. It effectively forces water from the outlet of the boiler to the inlet of the boiler during startup to reduce the period of time the boiler is operating below dewpoint temperature (usually 140 F) this period of operation is when creosote forms the quickest and is most acidic. Once the temp in the boiler jacket warms up the thermovar slowly starts to open up and circulate water to the house. Installation of a thermovar or equivalent was also a warranty requirement that many folks skipped as they didnt understand the importance and went cheap with the installation as they are pricey. Operation with storage, dependent on the piping arrangement, usually minimizes the period of "cold" operation thus reducing this creosote generation and corrosion phase.

Note there have been several boiler firms that went out of business who came up with an untested design and the boiler rotted out prematurely due to fire side corrosion. They went bankrupt and customers were left in the lurch with boilers that effectively were unrepairable due to design flaws.

As you have noted, the biggest issue are safety, convenience and fuel usage. A boiler without storage is going to build up far more creosote especially in the spring and fall (shoulder seasons). That means have to clean the chimney and boiler heat exchanger areas more often. If you skip that you could have an out of control fire one day in the heat exchanger area of the boiler and the chimney. My guess is if it is in an outbuilding, it has got a short stack so most of the creosote forming tars are being dumped into the local air instead of building up in the chimney but at some point, the creosote that does build up can turn into some very high heat content glaze. Get the right conditions and you definitely can permanently damage the boiler by overheating the heat exchanger section of the boiler. As for convenience, the more hassle to use it, the less it gets used. I used to run my older wood boiler without storage and due to the hassle I used far more heating oil. Once the storage went in and I got into a routine I used it more often and have not bought oil for 6 going on 7 years. Fuel usage is the last issue. A Tarm gasifier will not gasify very well if at all with green or partially dried wood. It means a longer start up burn with the bypass damper open until it hopefully gets up to temperature. Dry wood takes time and takes up space to dry and store it. Its lot easier and takes up less space to store smaller volumes of wood. Many folks get into the "dog chasing its tail" mode where they need a lot of wood to stay warm and dont have time to process it so they burn wet wood as they do not have the time to process it and burning wet wood means they need even more wood.

So now my true "horror" story. My neighbor in Northern NH built a really nice tight log sided home 25 years ago. His wife wanted a big fieldstone fireplace surrounded by glass on either side so they built it. Fieldstone fireplaces look great but rock does not insulate well. That meant their heating costs were quite high so he went cheap after a couple of winters of high heating bills and got a used older model Tarm. He installed it without storage and got a big load of green wood in the spring. He slowly cut and split it over the summer and started burning. The first chimney fire happened early in the winter and continued every month or so. He started out paying to have it cleaned and then started doing it himself. He eventually chained a ladder to the top of the two and half story stack. Its a PITA, so easy to let it slip and the result would be a chimney fire. Eventually he had a real hot one and they chimney tile cracked. That meant a new insulated liner was installed which was supposed to solve the creosote problem. It helped but he continued to have chimney fires less often but he still needed to clean it on occasion. After one particularly hot one, the liner "melted" making it unusable. Not sure if it actually melted but chimney fires can do strange things. He ended up the winter burning lots of heating oil and went with an illegal outdoor wood boiler the next summer. His chimney fires went away as the creosote just runs back down into the boiler. The result is 8 cords of wood per year, very poor local air quality around his house and the neighbors including myself and more heating oil as his wife is unwilling to put up with the odor during spring and fall. He also had to add a 2 story stack on it and a utility pole to support it to try to reduce the local air quality issues. I think the house will be up for sale next summer. I wonder if he is going to keep the OWB as it and its stack looks like crap next to a 500K home.

BTW I have the identical model Tarm sitting in my garage stored that was removed from a local home. It was installed by well regarded licensed plumbing and heating contractor without storage sharing a flue with at least an oil boiler and possibly another wood stove on an upper floor (illegal). The piping and workmanship was neat and tidy and included a thermovar but the owner wanted it gone after several years because she didnt trust the tenants who would be renting the house in the winter to be able to run it. The guy who installed it has an outdoor wood boiler without storage. Few heating contractors have any training on wood boilers system design, they treat them like a propane or heating oil boiler and unless the wood boiler distributor like Tarm tried to get them installed correctly by withholding the warranty, Tarm ended up getting blamed for crappy installations. NY state has a free online course on how to install wood boilers properly to get generous state incentives and it requires storage.

 

[salecker]

Tell your friend to pound sand if he doesn't believe you.
It's your house ,you are right and he should follow your directions.
Tell him politely if that will help, but stand your ground.
I built my system 13 years ago,after i spent months reading on here.The guy who helped me knew his stuff,i told him what i wanted to do.He was in total agreement even though there was never a sytem like mine built in the Yukon that he knew about.He was also the dealer for Econoburn at the time.

 

[pettibone]

I have the same boiler with no storage and have no issues with creosote but think it would be better with storage. Just picked up a stainless tank for storage just have to figure out hooking it up. But no way I'm buying oil at 5.50 per when I can heat with wood. I have all the original papers with mine and the guarantee says nothing about storage.

 

[Patti]

You have ticked off most of the reasons why folks use storage. Normally a boiler is installed inside the conditioned space (or adjacent to it like in a basement) so that heat loss from the boiler or the storage is not wasted. As for structural damage to the boiler I am not sure how much is done by operation without storage. Creosote can be acidic and when it builds up thickly, it can be more agressive at attacking steel so this type of operation will need to be cleaned far more often or the boiler could rot out. I say "could" as Tarm's in general were pretty robust units and my guess is they were overbuilt so that fireside corrosion is less of an issue.

I am not familiar with the newer Tarm designs on how they control boiler over temperature conditions, the older ones had a air damper that closed when the amount of heat being produced by the boiler exceeded the amount of heat being asked for from the house via the thermostats. Some systems have heat dumps so if the demand doesnt match supply they just dump heat to dump zone.

I am assuming that the installation is equipped with a thermovar valve (broken link removed to https://store.tarmusa.com/collections/thermostatic-valves) that minimizes low temperature operation during startup?. It effectively forces water from the outlet of the boiler to the inlet of the boiler during startup to reduce the period of time the boiler is operating below dewpoint temperature (usually 140 F) this period of operation is when creosote forms the quickest and is most acidic. Once the temp in the boiler jacket warms up the thermovar slowly starts to open up and circulate water to the house. Installation of a thermovar or equivalent was also a warranty requirement that many folks skipped as they didnt understand the importance and went cheap with the installation as they are pricey. Operation with storage, dependent on the piping arrangement, usually minimizes the period of "cold" operation thus reducing this creosote generation and corrosion phase.

Note there have been several boiler firms that went out of business who came up with an untested design and the boiler rotted out prematurely due to fire side corrosion. They went bankrupt and customers were left in the lurch with boilers that effectively were unrepairable due to design flaws.

As you have noted, the biggest issue are safety, convenience and fuel usage. A boiler without storage is going to build up far more creosote especially in the spring and fall (shoulder seasons). That means have to clean the chimney and boiler heat exchanger areas more often. If you skip that you could have an out of control fire one day in the heat exchanger area of the boiler and the chimney. My guess is if it is in an outbuilding, it has got a short stack so most of the creosote forming tars are being dumped into the local air instead of building up in the chimney but at some point, the creosote that does build up can turn into some very high heat content glaze. Get the right conditions and you definitely can permanently damage the boiler by overheating the heat exchanger section of the boiler. As for convenience, the more hassle to use it, the less it gets used. I used to run my older wood boiler without storage and due to the hassle I used far more heating oil. Once the storage went in and I got into a routine I used it more often and have not bought oil for 6 going on 7 years. Fuel usage is the last issue. A Tarm gasifier will not gasify very well if at all with green or partially dried wood. It means a longer start up burn with the bypass damper open until it hopefully gets up to temperature. Dry wood takes time and takes up space to dry and store it. Its lot easier and takes up less space to store smaller volumes of wood. Many folks get into the "dog chasing its tail" mode where they need a lot of wood to stay warm and dont have time to process it so they burn wet wood as they do not have the time to process it and burning wet wood means they need even more wood.

So now my true "horror" story. My neighbor in Northern NH built a really nice tight log sided home 25 years ago. His wife wanted a big fieldstone fireplace surrounded by glass on either side so they built it. Fieldstone fireplaces look great but rock does not insulate well. That meant their heating costs were quite high so he went cheap after a couple of winters of high heating bills and got a used older model Tarm. He installed it without storage and got a big load of green wood in the spring. He slowly cut and split it over the summer and started burning. The first chimney fire happened early in the winter and continued every month or so. He started out paying to have it cleaned and then started doing it himself. He eventually chained a ladder to the top of the two and half story stack. Its a PITA, so easy to let it slip and the result would be a chimney fire. Eventually he had a real hot one and they chimney tile cracked. That meant a new insulated liner was installed which was supposed to solve the creosote problem. It helped but he continued to have chimney fires less often but he still needed to clean it on occasion. After one particularly hot one, the liner "melted" making it unusable. Not sure if it actually melted but chimney fires can do strange things. He ended up the winter burning lots of heating oil and went with an illegal outdoor wood boiler the next summer. His chimney fires went away as the creosote just runs back down into the boiler. The result is 8 cords of wood per year, very poor local air quality around his house and the neighbors including myself and more heating oil as his wife is unwilling to put up with the odor during spring and fall. He also had to add a 2 story stack on it and a utility pole to support it to try to reduce the local air quality issues. I think the house will be up for sale next summer. I wonder if he is going to keep the OWB as it and its stack looks like crap next to a 500K home.

BTW I have the identical model Tarm sitting in my garage stored that was removed from a local home. It was installed by well regarded licensed plumbing and heating contractor without storage sharing a flue with at least an oil boiler and possibly another wood stove on an upper floor (illegal). The piping and workmanship was neat and tidy and included a thermovar but the owner wanted it gone after several years because she didnt trust the tenants who would be renting the house in the winter to be able to run it. The guy who installed it has an outdoor wood boiler without storage. Few heating contractors have any training on wood boilers system design, they treat them like a propane or heating oil boiler and unless the wood boiler distributor like Tarm tried to get them installed correctly by withholding the warranty, Tarm ended up getting blamed for crappy installations. NY state has a free online course on how to install wood boilers properly to get generous state incentives and it requires storage.

Thank you so much for your detailed reply peakbagger!
Although…I panicked and my heart started racing when I read your first line 😂😂😂
I thought the next word was going to be ‘people’ and I felt terrible!
(Well- just for a second -until I read the words that followed! 😂😂😂)

Man…that IS a horror story!! 😳

Now…if one builds a house such as that one…(I’m guessing it’s pretty darn nice for $500,000!)… I have to ask…why wouldn’t they have gone right to the Cadillac and got a Fröling? ☺️ I think the majority of people using gasifiers would probably say that if they weren’t so expensive, they would be the manufacturer of choice. Do you think that?

I’m assuming he had it installed by someone? It sounds like they didn’t offer much product support afterwards, which is too bad.

It sounds like he didn’t do his homework, that’s for sure-because
Yup! -DRY WOOD is the key!
I’ve finally started to get ahead by a couple years! Mine’s been cut, split & either stacked or piled outside. Then I bring it in the shop, where it has ceiling fans going above it 24/7. I am always testing my wood, and depending on the species, my moisture levels range between 5- 10%, which I’m happy with.

I was just trying to think of how many cords I went through last year…(but my brain is too tired to start calculating at the moment). I’m going to ‘guess’ roughly 15-18.
(grrr😡). Wayyy too much- and it wasn’t even started until the first week of January 😖
I’m hoping that 7-8 is a more realistic number!

Yes, you’re right about those Tarms being like tanks!!
Are you going to install the one you have for your own personal use, or are you going to sell it?

I’m still looking around for someone who could come and test my flue gases and such. I’d like to be sure I’m burning it properly, but there doesn’t seem to be many guys around here that deal with gasifiers. 🤷‍♀️

I think my smokestack is 15’ above my roof, so that helps…a bit…
Whenever I clean my chimney there’s a surprisingly small amount of creosote, so that makes me happy! 😊
Thanks again for your input and sharing your experiences. I learn something new every time I’m on the site!! 👍

 

[maple1]

You can make things worse by adding storage. If it's not done right. And sounds like he won't be much help in making sure it's done right. So this will be all on you - to make sure it's done right. The thing of critical importance being, return temperature protection. Being done right.

Edit: that is assuming you have the right tank for the job.

 

[sloeffle]

I was just trying to think of how many cords I went through last year…(but my brain is too tired to start calculating at the moment). I’m going to ‘guess’ roughly 15-18.
(grrr😡). Wayyy too much- and it wasn’t even started until the first week of January 😖
I’m hoping that 7-8 is a more realistic number!

Are you talking full cords or ricks / bush cord ( 1/4 cord )? If you are burning that much wood that would be a full time job, almost.

I’ve finally started to get ahead by a couple years! Mine’s been cut, split & either stacked or piled outside. Then I bring it in the shop, where it has ceiling fans going above it 24/7. I am always testing my wood, and depending on the species, my moisture levels range between 5- 10%, which I’m happy with.

Are you checking a freshly split piece of wood on the face ? Most dry firewood is between 15-20% moisture, not unless you live in a desert or it has been kiln dried. Wood is hygroscopic, it's going to gain and release moisture throughout the various seasons.

 

[peakbagger]

As to how and wny my neighbor did what he did, I dont care to guess.

The Tarm he put in was a used non gasifier version very similar to my ancient Burnham . It had been hauled to the dump by a prior owner and someone dragged it out. Nothing wrong with that but whoever installed it thsi time just hacked it in. Storage is an expensive addon and it requires some design knowledge to do it right. Few HVAC folks have the background. Here is a course that NY state sponsors from probably the number one heating pro in the country https://www.heatspring.com/courses/hydronics-for-high-efficiency-biomass-boilers. Most folks are shocked at what a proper installation would cost even if the labor is free.

My house is small and fairly tight, I bought the storage to match the Burnham boiler and with a new somewhat complex control system it works pretty well. The Tarm I bought has a higher output and my 500 gallons of storage is too small to really compliment it. I live not that far from the Canadian border (about an hour) in Northern NH so my heating load is fairly high but I only burn 3 to 4 cords of dry wood a year for all my heating so its not really worth spending the money and time to swap in the new boiler. I am considering building a new house and that Tarm will probably get installed, otherwise I expect I can sell it for more than I paid for. Tarm used to build their own boilers but this model was actually built by another firm in Eastern Europe and dressed up as a Tarm and then imported by Tarm. They got out of that business and the folks in Lyme NH found anothee line of European boilers to import, Froling.

If you are not seeing a lot of creosote than you are burning fairly well especially if you truly are using that much wood. It implies you are heating a "barn" so that the boiler does not idle that often. Storage only makes a big difference when that the boiler had to idle frequently.

 

[cpeltier]

I have a Tarm Solo Plus 60 and I’ve been running it hard for 20 years with absolutely no issues. I have 750 gallons of pressurized storage and I run it flat out in batch mode. It parallel’s a propane boiler. Chimney only has light fly ash never any creasote to clean. Very low maintenance setup. Wouldn’t do it any other way.

 

[TimfromPittsburgh]

Mine is a Tarm 502 (with oil backup) installed in 1996 with no heat storage or thermovar valve to modulate water temperature at the boiler inlet. Incidentally this was before I discovered this forum (possibly before this forum even existed). Over the years I added heat storage and a thermovar so I think I have gained some perspective on how these upgrades have affected performance of my boiler.

The Tarm 502 is a purely mechanical system where primary air to the fire is controlled by an aquastat that opens and closes the primary air door based on boiler water temperature whereas the the newer Tarm gassifier models employ electronic controls to manage combustion. I believe the heat exchanger section (fire tubes) of both older and newer Tarms is about the same (i.e. six heat exchanger tubes about 3" in diameter by 24" long). The problem I encountered prior to adding heat storage was a buildup of a sticky tar-like coating on the inside of the fire tubes which was very difficult to remove and I am certain significantly reduced boiler efficiency. I came to learn that this tarry substance was produced when the boiler was idling (boiler water temperature at upper limit and no demand). Since adding storage my boiler spends very little time idling and tarry deposits on the fire tubes is no longer an issue. Now there is a coating of ash that is easy to remove.

A further advantage to having heat storage is that the cycling of boiler water temperature is greatly reduced which, in turn, reduces thermal stress on the boiler itself. I can't comment on overall firewood consumption pre and post storage as that would necessitate a lot of record keeping which I have not done. I can say that the convenience of heat storage is huge.

 

[cpeltier]

Mine is a Tarm 502 (with oil backup) installed in 1996 with no heat storage or thermovar valve to modulate water temperature at the boiler inlet. Incidentally this was before I discovered this forum (possibly before this forum even existed). Over the years I added heat storage and a thermovar so I think I have gained some perspective on how these upgrades have affected performance of my boiler.

The Tarm 502 is a purely mechanical system where primary air to the fire is controlled by an aquastat that opens and closes the primary air door based on boiler water temperature whereas the the newer Tarm gassifier models employ electronic controls to manage combustion. I believe the heat exchanger section (fire tubes) of both older and newer Tarms is about the same (i.e. six heat exchanger tubes about 3" in diameter by 24" long). The problem I encountered prior to adding heat storage was a buildup of a sticky tar-like coating on the inside of the fire tubes which was very difficult to remove and I am certain significantly reduced boiler efficiency. I came to learn that this tarry substance was produced when the boiler was idling (boiler water temperature at upper limit and no demand). Since adding storage my boiler spends very little time idling and tarry deposits on the fire tubes is no longer an issue. Now there is a coating of ash that is easy to remove.

A further advantage to having heat storage is that the cycling of boiler water temperature is greatly reduced which, in turn, reduces thermal stress on the boiler itself. I can't comment on overall firewood consumption pre and post storage as that would necessitate a lot of record keeping which I have not done. I can say that the convenience of heat storage is huge.

My neighbor has your boiler and I remember seeing the brochures on that 25 years ago!
One thing you can do since you’re only dealing with fly ash now in the boiler tubes is add turbulaters. I added them to my Tarm Solo and found some in an old oil boiler that I cut back. It definitely lowers the stack temperature and more of your heat ends up in storage. My Solo plus 60 is all mechanical and runs flawlessly.

 

[JMihevic]

My boiler is a Tarm MB 55 that I bought in 1980 when I built my house. I have a 2 row hot water coil installed above my heat pump air handler that heats my 2,000 sq. ft. house. Also, I have a 40 gallon Amtrol boiler mate that supplies all our hot water for the house. I have been using the boiler every winter now going on 43 years. Trouble free with no maintenance issues, other than replacing the thermal element in the Samson draft regulator once. The MB 55 came out before the 502 and doesn’t have the fire tube heat exchanger like the 502. The heat exchanger at the back is simply a plate heat exchanger that I clean by scraping the walls with the scraper that came with the boiler. Probably I lose some efficiency with the flat plate compared to the tubular heat exchanger. But cleaning is very simple with the scraper. I scrape the heat exchanger once a year (at the same time I clean the chimney). Cleaning is very easy as the creosote is very flakey and comes right off. There is the hard glazed creosote that is all over the boiler walls. When I first got the boiler, I tried to get that creosote off down to the steel of the boiler walls. This was next to impossible. What I have found with time, the tar like creosote hardens and becomes thicker on the walls. With a hot fire, the hard creosote, burns off to a flakey creosote that is easy to scrape off. As a result, the hard glazed creosote never gets above a small coating on the boiler walls.

A few days ago, when the outside temp was 3 degrees below zero, our house was at 72 degrees. At this condition, I could still have increased the water flow for more heat. I keep my house at a constant 72 degrees. Based on outside air temp, I match the boiler heat output to the heat loss at a given outdoor temperature. This makes it very comfortable in our house with no variation in indoor temperature. Boiler operation makes it more comfortable in the house than when the heat pump is maintaining the house temperature. The worst winter I have gone through with the MB 55 was when the outside temp was 20 degrees below zero. With my Tarm there was no problem maintaining indoor house temperature.

One other note. I have absolutely no corrosion/rust problem with the steel in the boiler walls. The secret is the 60 watt resistance heater I have in the boiler when not in operation during the summer months when the humidity is high. The boiler wall temperature is always above the ambient air dew point temperature. AS a result, there is never water condensate on the walls. Condensate on the boiler walls in combination with the corrosive chemicals in the creosote is an absolute condition for destruction of the boiler.

John M.

 

[TimfromPittsburgh]

My neighbor has your boiler and I remember seeing the brochures on that 25 years ago!
One thing you can do since you’re only dealing with fly ash now in the boiler tubes is add turbulaters. I added them to my Tarm Solo and found some in an old oil boiler that I cut back. It definitely lowers the stack temperature and more of your heat ends up in storage. My Solo plus 60 is all mechanical and runs flawlessly.

I actually did add turbulators last year (along with a homemade flue temperature regulator) in attempt to better control flue temperature. I'm pleased to report that I can now set the desired flue temperature and the boiler will maintain it to within +/- 50 degrees or so. Since I did both enhancements at about the same time I can't say how much adding turbulators improved boiler operation, but understanding the purpose for turbulators I'm certain they are they are making a big contribution to boiler performance.

Prior to installing the flue temperature regulator it was a continuous battle to maintain a reasonable flue gas temperature. I installed both a barometric and manual dampers which needed a lot of adjusting in order to keep flue temperature under control under varying weather conditions. Life with my Tarm 502 is definitely better now!

 

[TimfromPittsburgh]

My boiler is a Tarm MB 55 that I bought in 1980 when I built my house. I have a 2 row hot water coil installed above my heat pump air handler that heats my 2,000 sq. ft. house. Also, I have a 40 gallon Amtrol boiler mate that supplies all our hot water for the house. I have been using the boiler every winter now going on 43 years. Trouble free with no maintenance issues, other than replacing the thermal element in the Samson draft regulator once. The MB 55 came out before the 502 and doesn’t have the fire tube heat exchanger like the 502. The heat exchanger at the back is simply a plate heat exchanger that I clean by scraping the walls with the scraper that came with the boiler. Probably I lose some efficiency with the flat plate compared to the tubular heat exchanger. But cleaning is very simple with the scraper. I scrape the heat exchanger once a year (at the same time I clean the chimney). Cleaning is very easy as the creosote is very flakey and comes right off. There is the hard glazed creosote that is all over the boiler walls. When I first got the boiler, I tried to get that creosote off down to the steel of the boiler walls. This was next to impossible. What I have found with time, the tar like creosote hardens and becomes thicker on the walls. With a hot fire, the hard creosote, burns off to a flakey creosote that is easy to scrape off. As a result, the hard glazed creosote never gets above a small coating on the boiler walls.

It's really encouraging to hear about Tarm boilers in operation for 40, even 50 years. I would be so pleased to get 50 years use from my Tarm. I absolutely agree the key to boiler longevity is doing the maintenance.

One other note. I have absolutely no corrosion/rust problem with the steel in the boiler walls. The secret is the 60 watt resistance heater I have in the boiler when not in operation during the summer months when the humidity is high. The boiler wall temperature is always above the ambient air dew point temperature. AS a result, there is never water condensate on the walls. Condensate on the boiler walls in combination with the corrosive chemicals in the creosote is an absolute condition for destruction of the boiler.

My Tarm has oil backup, so during the off-season I let the oil burner keep the temperature in the water jacket at 100 degrees or so. With the price of heating oil so high it might make sense to switch to an electrical heating element. My owner's manual for the 502 stresses the importance of not allowing condensation to occur in the firebox. early on in its life a black coating was deposited on the surface of the firebox which hardened to the point where it behaves like a coat of paint. On occasions when I have scratched through this coating I see shiny metal beneath. I also use the scraper tool supplied with the boiler to remove the flaky crust that forms on top of the black coating.

wishing you continued good service from your Tarm boiler.

 

[glhenry56]

It's really encouraging to hear about Tarm boilers in operation for 40, even 50 years. I would be so pleased to get 50 years use from my Tarm. I absolutely agree the key to boiler longevity is doing the maintenance.

My Tarm has oil backup, so during the off-season I let the oil burner keep the temperature in the water jacket at 100 degrees or so. With the price of heating oil so high it might make sense to switch to an electrical heating element. My owner's manual for the 502 stresses the importance of not allowing condensation to occur in the firebox. early on in its life a black coating was deposited on the surface of the firebox which hardened to the point where it behaves like a coat of paint. On occasions when I have scratched through this coating I see shiny metal beneath. I also use the scraper tool supplied with the boiler to remove the flaky crust that forms on top of the black coating.

wishing you continued good service from your Tarm boiler.

Tim,
I really enjoyed reading your posts about your 502. Mine was built in '85, bought new in '90 (it was a floor model), and still runs great after 34 heating seasons. Based on your post, it looks like mine has many more good years ahead! I also have that thin 'hard black' layer on the combustion walls that you mentioned, and no sign of corrosion at all. I always leave the boiler down during non-heating season. We recently decided to go to an oil-only boiler (several reasons) and now have the old girl in the garage, ready for its next owner. I replaced the domestic coil gasket, which allowed me to inspect the water side - also corrosion free (see pics). The 502's may not have the higher tech, super-efficient burns of Tarm's newer models, but they certainly are solid workhorses. I will truly miss mine.