# Tarm Solo Plus vs. Tarm Solo Inova



## hd28vsb (Feb 3, 2009)

Can someone give me some insight on the differences in the boilers.
What are the + and - of each one.
The Innova looks to be more efficient . Noticed the Innova has a thinner firebox than the solo . 
Will one hold up as well as the other in the long run ?

Thanks


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## flyingcow (Feb 6, 2009)

I've got an Innova. Only had it in service since Jan 17th. Starts very easy(throw kindlin' in, light paper, wait maybe a minute, throw wood in, shut door, and leave) , very, very little smoke when opening the door. Different draft system than the solo. Ideal for basement,but mines in a garage. From when I touch the kindlin' off, I'll usually have 165 degree water circulating(in about 35 minutes), and very soon after have 180 climbing to 200 in a hurry. You need to have storage with it. Had ordered a solo, but were back ordered, could get the Innova quicker.


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## BrownianHeatingTech (Feb 6, 2009)

The Innova requires thermal storage, but will release less smoke during loading and, as noted, is more efficient.  The Innova is more expensive (though not by much).

In my business, I really don't even bother with the Plus, now that the Innova is here, although I understand that some folks are really set on doing an installation without storage, and obviously will need to use the Plus.

That's my opinion on the matter, anyway.

Joe


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## hoth2oguy (Feb 7, 2009)

yup.  Really, if you are able to go with thermal storage right away, the Solo Innova makes the most sense (modest increase in price, easier to use and more efficient).  If you are not able to add storage with the original install then you would choose the Solo Plus.


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## chuck172 (Feb 7, 2009)

Chris Hoskin said:
			
		

> yup.  Really, if you are able to go with thermal storage right away, the Solo Innova makes the most sense (modest increase in price, easier to use and more efficient).  If you are not able to add storage with the original install then you would choose the Solo Plus.


Then wouldn't the owners of the Solo Plus without storage benefit from a thermostatically controlled variable speed fan? Since idling is the big issue. 
This would possibly provide gasifaction at a lowered output, and the boiler might idle less.
Some other boiler manufacturers provide this. 
It might be a good retro-fit kit from Tarm.


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## hoth2oguy (Feb 8, 2009)

Chuck172, not sure if variable speed fan would be beneficial or not.  The pellet boilers step down from 100% fan speed to 30% fan speed once boiler temp is within three degrees C of set point.  I suppose something like this would not be hard to set up on a Solo Plus.  I think it would take some experimenting to see how much you could reduce fan speed and still get decent gasification.  Would be very curious to hear anyone's experience if they try it.


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## hoth2oguy (Feb 8, 2009)

hd28vsb, I just re-read your original post and noticed you asked about boiler/firebox wall thickness.  The Solo Innova walls may be a bit thinner, but they are also shielded by additional 5mm (I think) thick steel aprons that line the primary firebox.  The key thing, however, is that because the Solo Innova is being used with storage it should not be subjected to the creosote and condensation build up that can prematurely rot out a steel boiler.  In other words, the Innova should last at least as long as the Solo Plus.


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## jebatty (Feb 8, 2009)

In addition to variable fan speed to reduce gasification, chimney draft also needs to be controlled, and these two are somewhat independent. I have a speed control on the draft fan on my Tarm, and it does work to slow down gasification. Depending on temperature, wind, and other factors affecting draft, however, slowing down the draft fan does not always result in a lower draft being pulled through the firebox by the chimney, as measured by stack temp. Another consideration is the MC of the wood load, which often varies somewhat from load to load, even with wood from the same stacks that have been seasoned the same length of time. Drier wood generally burns hotter and gives off more gas more quickly. Another consideration is even if gasification is slowed down, is the firebox turning out wood gases that due to reduced air flow are not being combusted in the gasification tunnel and simply escaping up the chimney? If this is happening, then the boiler is operating in part just like an ordinary wood stove. It seems to me that although likely possible, the parameters to be measured and controlled to achieve the most efficient final combustion are several and interrelated, and achieving the desired result is fairly complex.

This for me all gets back to the ultimate goal of achieving nearly complete combustion/gasification, on the one hand, and, on the other, capturing as much of the resulting heat as possible without condensation of the final flue gases. I have to assume that the Tarm is pretty well engineered to achieve nearly complete combustion. 

As to capturing the heat, I am limited by the hx tube engineering in the Tarm, which I have supplemented by adding the chain turbulators combined with regular cleaning of the hx tubes. I also have plenty of storage which greatly has reduced idling, although idling begins and then increases as tank temp rises. This means that the Tarm is transferring more heat to its boiler water than my system demand (actual demand plus storage demand) can use. 

The "simple" solution appears to be a modulated demand heating system that can absorb the extra heat when needed to prevent boiler idling.

What about a 2-stage storage system, combined with a heating system that can efficiently operate at, say, 110-130F water (assumed "no-idling" range for boiler)? The primary stage storage would be relatively large and the secondary stage storage relatively small. System demand would first deplete the secondary storage to as low a temp as would be usable, then switch to the primary storage until it approached low temp. The boiler then would be fired, first to raise the primary storage to the  "no idling" temp, and then until the wood load was burned out switch to raise the secondary as needed. Since the secondary would start at a very low temp, there should be no idling as the wood load burned to completion.


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## Nofossil (Feb 8, 2009)

jebatty said:
			
		

> What about a 2-stage storage system, combined with a heating system that can efficiently operate at, say, 110-130F water (assumed "no-idling" range for boiler)? The primary stage storage would be relatively large and the secondary stage storage relatively small. System demand would first deplete the secondary storage to as low a temp as would be usable, then switch to the primary storage until it approached low temp. The boiler then would be fired, first to raise the primary storage to the  "no idling" temp, and then until the wood load was burned out switch to raise the secondary as needed. Since the secondary would start at a very low temp, there should be no idling as the wood load burned to completion.



This is in effect a way of artificially creating stratification. A system with really good stratification does this automagically.

One of the 'lessons learned' for me is that you ideally want to design your system with as large a delta T during operation as possible. I'd love to have enough radiant so that I could supply a small amount of 180 degree water in and get back water at 90 degrees. I'll never be able to do that, but I'm setting up my radiant zone as a secondary loop (closely spaced tees) that pulls from the return manifold after the water has passed through the baseboard zones, hopefully dropping the return temp a few more degrees.


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## twitch (Feb 9, 2009)

nofossil - 

I have a very simple setup, Scandtec Solo 30 with an air handler, no storage.  With my grundfos on meduim speed and the air handler on high (hardwired), I'm getting about a 20 degree delta T.  Does your ideal delta T only apply when using storage?  I could turn down my circ to get a larger delta T, but not sure what the difference would be.


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## Hansson (Feb 9, 2009)

The walls in the innova firebox is 7mm thick.If you ha a storage tank the innova is a better choice.


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## hd28vsb (Feb 9, 2009)

If not mistaken , the literature I have states the Innova firebox  is 6mm thick. And the Solo is 7mm.
but thats only .039  difference  , not a whole lot in the big picture i guess.


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## Hansson (Feb 10, 2009)

The solo plus firebox 7mm the innova firebox 7mm says literature here.
The solo plus is not sold over here any more..


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## Rory (Feb 10, 2009)

You guys are killing me.   My dealer told me that the only difference between the new Tarm and the old was the outer door.   Smoke escapement is a huge issue in my house, and I would have sprung for the Innova if I'd have known that there was a difference.


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## hoth2oguy (Feb 11, 2009)

Rory, the difference between the old Solo PLUS and the new Solo PLUS is the outer door.  My guess is the Solo INNOVA was not available when you bought your Solo Plus, we have only had them for a couple of months.  If you have not done so already, give your dealer or us a call to talk about ways to minimize smoke roll-out.  Don't beat yourself up too badly, the Solo Plus is a great boiler and we should be able to minimize the smoke issue for you.  Best,

Chris


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## oldmilwaukee (Feb 11, 2009)

Once I re-read the manual and realized it said _open the door 3/4" for 20 seconds_ and not _open the door 3/4 for 20 seconds_, the smoke rollout became a non-issue.    So far, with less than 1 week of experience of using the boiler, the Tarm Solo is exceeding my expectations.  I must admit a tinge of envy wondering what the newer model is like, but the fact that there is a newer model does not make the previous model any less capable than it was before.  Ever been married? Ha ha... I better not go there.


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## flyingcow (Feb 11, 2009)

oldmilwaukee said:
			
		

> Once I re-read the manual and realized it said _open the door 3/4" for 20 seconds_ and not _open the door 3/4 for 20 seconds_, the smoke rollout became a non-issue.    So far, with less than 1 week of experience of using the boiler, the Tarm Solo is exceeding my expectations.  I must admit a tinge of envy wondering what the newer model is like, but the fact that there is a newer model does not make the previous model any less capable than it was before.  Ever been married? Ha ha... I better not go there.



Read part of your house blog. Liked the thread about pipe thread.  Nice looking house, fireplace,etc. When I get time I'll finish reading the rest of it.


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