Hi..have Tarm Solo 40 installed since last December...with storage added a few months later...American Solartechnics 820 and it is now working well, owner of this company stands behind his product, for those of you looking for water storage tank solutions....this is a very good solution. I have seen some who have tried to add storage with homemade tanks that include "pond" liners from home depot and such....those are most likely not rated for the type of temps required, and that is why we decided to go with the people who design for this type of need. Tom from Maine (American Solartechnics) has been very helpful, dealt with the problem we had and didn't go hide when we were in need of answers. Anyway, to the subject....I am wondering if any of you Tarm users who have been burning for a while could upload some photos of the inside of your smoke box ......I would like to see how it compares to mine......also wondered why the unit would not take all the heat thrown at it ....when running a good fire the boiler gets up there to 175 or so and is sending heat to the storage tank, but the tank seams not to be able to always take all the heat being sent....sometimes the boiler goes into idle mode even though the the tank temps are below the 140's ...any thoughts? Thanks
TARM SOLO 40 USE/EXPERIRENCEs AND QUESTIONS
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Do you have a balancing valve between the boiler supply and the termovar (assuming you have one), and if so how do you have it set? I initially set mine at about half off, then had to go a little more to get hot water to my air handler.
I have standart Tarm set up with Termovars and the balancing valve ...set at half ...have never tried to change it as I am not sure witch way to go...did you close yours off some more..and what did that accomplish for you
The company I bought the boiler from did the near boiler piping and didn't put in a balancing valve, so I am currently using the termovar isolation valve for this purpose (not ideal, but it works). I had to close it a little more than half way to force the hot water out to the load rather than back to the return. You obviously don't want to shut it off completely, but try a little bit at a time. If you have a valve with a single handle it is wide open when the handle is parallel to the pipe, and shut off when the handle is perpendicular to the pipe.
Tarm's material suggested this at half way .....but if we close it a little, it will then direct more heat to the storage tank (or house) .....and cool down water to the boiler return? Which then would allow the boiler to not reach idle because it is sending more heat to the load? ......I thought the termovar valves handled that part thermostatically....While I am here, does anyone use the BLT control sold by Tarm and have the autobackup feature in use ...which would kick the backup (oil) on when heat in the storage tank falls below the set point on its aquastat....I am wondering if anyone uses the auto backup to handle not only heat to the house but DHW as well.....mine right now leaves the DHW off and only the heat kicks on when the auto backup kicks in ....I am looking for ways to incorporate the DHW into that loop as well....Does that mean thermostatic valves on the Original DHW tank that will also be kicked on when the auto backup kicks in...
Glad things are working out well. As to the Terovar balancing valve setting, make it easy on yourself by getting a probe meat thermometer or "milk frothing thermometer" (search ebay), cable tie it to the boiler return water pipe after the Termovar, wrap it with insulation, and then monitor the actual temp of your return water. Set the balancing valve to maintain (IMO) minimum return water of 140F, or higher up to 160F. Once set, you usually can leave this alone, but if sysem return water is consistently 140F or higher, might want to close the Termovar down a little more, again watching the actual return temperature so that it is not higher than 160F unless system return water is higher than 160F.
As to your other questions ...
Such photos have been posted, but suffice to say that the smoke box cover, the walls of the smoke box and the plate on top of the hx tubes will collect a moderate amount of flyash over a period of a couple of weeks, should be no creosote of any consequence, and flyash and other accumulations in the smoke box surfaces should easily brush off into dusty material. Vacuum it up or scrape it down the hx tubes, brush the hx tubes regularly, and then pull out the accumulated ash in the bottom of the refractory chamber. Also vacuum out the short flue pipe run from the back of the smoke box to your vertical flue pipe run. IMO, a cleaning every two weeks, or at least when you notice flue temps rising, is good practice -- then brush the hx tubes also. I'm on a pretty consistent 2 week schedule.
The storage tank not taking all the boiler output is a simple equation of btu transfer, which relates to delta-T, gpm, and if an open system and a coil or plate hx, the efficiency of the heat exchanger to storage. Use the same milk frothing thermometers on you boiler to storage pipe and storage return to boiler pipe. That will give you the delta-T. You should be able to approximately, at least, compute your pump head in the boiler/storage loop. Take a look at the circ pump curve for your circ at the calculated pump head and you will have your approximate gpm. Gpm x 500 x delta-T = btu. I think that number, for delta-T=20F, should be about 75% (or higher) of your boiler rating in order to handle normal range of boiler output. Even then at times your boiler will have output greater than storage acceptance and you may experience some idling. But if much less than 75%, idling frequency will increase.
Assume 8 gpm. If delta-T = 20, you can move 80,000 btu output; if delta-T = 30, you can move 120,000 btu output. The higher your delta-T at a given gpm, the easier it is to handle boiler output, and vice versa.
If your tank return to boiler is 170, and boiler output is 185F (delta-T = 15), then you have to move 18 gpm to handle 135,000 btu output, almost the rated capacity of your Tarm, and I'm going to assume that your circ will not move 18 gpm through your boiler/storage loop. Consequence -- idling.
A tip. As your storage temp rises, time your burns or load for burns that are burning down towards the end of tank charging, as boiler output then is falling, and easier to top of your storage without much idling. If you're in high burn and storage is nearing capacity, your boiler output likely will be far in excess of storage capacity to receive at given gpm's. Consequence -- lots of idling.
If you're getting lots of idling and storage return to boiler is less than 140, then you do not have a very efficient hx in your open storage and/or your gpm in this loop is low. If boiler output is 180F, then delta-T = 40, and you only need 7 gpm to move 140,000 btu, your Tarm max rating. I suspect that if boiler output is 180F or higher, storage return is 140F, and you are experiencing idling, then your pump head is high and you are moving, perhaps considerably so, less than 7 gpm.
Hope this is helpful.
As to your other questions ...
Such photos have been posted, but suffice to say that the smoke box cover, the walls of the smoke box and the plate on top of the hx tubes will collect a moderate amount of flyash over a period of a couple of weeks, should be no creosote of any consequence, and flyash and other accumulations in the smoke box surfaces should easily brush off into dusty material. Vacuum it up or scrape it down the hx tubes, brush the hx tubes regularly, and then pull out the accumulated ash in the bottom of the refractory chamber. Also vacuum out the short flue pipe run from the back of the smoke box to your vertical flue pipe run. IMO, a cleaning every two weeks, or at least when you notice flue temps rising, is good practice -- then brush the hx tubes also. I'm on a pretty consistent 2 week schedule.
The storage tank not taking all the boiler output is a simple equation of btu transfer, which relates to delta-T, gpm, and if an open system and a coil or plate hx, the efficiency of the heat exchanger to storage. Use the same milk frothing thermometers on you boiler to storage pipe and storage return to boiler pipe. That will give you the delta-T. You should be able to approximately, at least, compute your pump head in the boiler/storage loop. Take a look at the circ pump curve for your circ at the calculated pump head and you will have your approximate gpm. Gpm x 500 x delta-T = btu. I think that number, for delta-T=20F, should be about 75% (or higher) of your boiler rating in order to handle normal range of boiler output. Even then at times your boiler will have output greater than storage acceptance and you may experience some idling. But if much less than 75%, idling frequency will increase.
Assume 8 gpm. If delta-T = 20, you can move 80,000 btu output; if delta-T = 30, you can move 120,000 btu output. The higher your delta-T at a given gpm, the easier it is to handle boiler output, and vice versa.
If your tank return to boiler is 170, and boiler output is 185F (delta-T = 15), then you have to move 18 gpm to handle 135,000 btu output, almost the rated capacity of your Tarm, and I'm going to assume that your circ will not move 18 gpm through your boiler/storage loop. Consequence -- idling.
A tip. As your storage temp rises, time your burns or load for burns that are burning down towards the end of tank charging, as boiler output then is falling, and easier to top of your storage without much idling. If you're in high burn and storage is nearing capacity, your boiler output likely will be far in excess of storage capacity to receive at given gpm's. Consequence -- lots of idling.
If you're getting lots of idling and storage return to boiler is less than 140, then you do not have a very efficient hx in your open storage and/or your gpm in this loop is low. If boiler output is 180F, then delta-T = 40, and you only need 7 gpm to move 140,000 btu, your Tarm max rating. I suspect that if boiler output is 180F or higher, storage return is 140F, and you are experiencing idling, then your pump head is high and you are moving, perhaps considerably so, less than 7 gpm.
Hope this is helpful.
I use the backup to control the OB and the DHW. I have a Bosch Tankless for DHW, so I simply have the storage tank aquastat control SS zone valves that guide the DHW flow through (for backup) or bypass the Bosch.beantaxi said:
You could use a relay activated by your backup. This relay would turn on your DHWH when backup is energized. I don't know your pipe config., so you may or may not need some zone valves to direct water flow.(as in my case, the DHW either flows through the Bosch or around it)
Jim, Excellent description That really tells the whole story. I do find that about 175* is all I can transfer to the tank, As the delta T gets lower the transfer gets tougher
Got the same tank and hx coils as you have. i have the loading valve option on my set up. The loading valve will shut off the mixing, basically close off the port when the boiler really gets cooking. the TV-2 will handle all my diversion to house or tank. this will put priority on house zones and at the same time it will feed extra btu's to tank. I think thats how all that stuff works. But, bean, i have no problem getting my tank to take all my heat. Will idle to the end of the burn, but i can't recall at what temp the tank is(keep in mind, my boiler is next door, 100ft away from the tank), but its up there. In the summer, i don't fire the boiler up until tank is 105/110( about the same way i do now). But keep in mind i've got 820gals of storage with a 102,000btu boiler. In the summer, I don't try to heat tank over 165ish. waste of wood. i am very impressed with these HX coils and how they handle the btus'. They extract the btu's quite nicely.The DHW coil will does a nice job. And i am happy with american solortechnics. Tom doesn't avoid a problem. He's got a lot of time and experience behind him. You might want to bounce this off of him. Or 1st i'd call tarm. Maybe email your problem first, they wiil get the preliminaries first, than talk face to face.
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