# Froling FHG-L 50 Install



## jebatty (Oct 12, 2011)

Excuse me if I drool a little, but you may too when you take a look at this install. The Froling will be heating a 6000 sq ft educational interpretive center at Deep Portage (DP) in north central Minnesota, an older building with poor to fair insulation, windows and doors. It will replace two LP hot air gas furnaces, which remain as backup units. It also will provide DHW. 

The Froling was installed in its own boiler shed adjacent to the building, which also houses a 1600 gallon hot water storage tank. Domestic hot water is provided from a standard hot water heater which is now equipped with an integrated double wall heat exchanger and mixing valve. The tank can be heated to as high a temperature as the Froling will provide, and the hot water is mixed down to 120F for domestic service. With the 1600 gallon boiler hot water storage tank, there will be plenty of hot water, and DP also expects to be firing the Froling during the summer, perhaps once per week, to provide DHW. 

This winter I should be able to do some temperature measuring and data logging and provide a performance report. And I am excitedly awaiting the opportunity to put the Froling through its paces. The installation finished yesterday. The Froling is operating, the system has being brought up to full temperature, and all components are in operation.


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## Singed Eyebrows (Oct 12, 2011)

There's been a grievious error, this was installed at the wrong location, Milwaukee was the proper site. The Froling is nice & it looks like a very well thought out install, Randy


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## Gasifier (Oct 13, 2011)

Jim,

Is that the extent of the insulation on that tank? It is going to be warm in that room to say the least. Nice set up. What does DP do again?


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## EffectaBoilerUser (USA) (Oct 13, 2011)

This looks like a very nice installation.

I look forward to seeing some perfromance graphs of the Froling.

Was there any problem (with local officials) installing this as a pressurized system even though the boiler is not ASME rated?

Thanks,

Brian


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## Gasifier (Oct 13, 2011)

Remembering that I am a newbie at these systems. What is that thing-a-ma-jig on the wall there in the last picture? And how does it work?


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## ewdudley (Oct 13, 2011)

Gasifier said:
			
		

> Remembering that I am a newbie at these systems. What is that thing-a-ma-jig on the wall there in the last picture? And how does it work?



Looks like a DHW flat plate heat exchanger.  Maybe has integrated pump with variable speed to adjust flow from storage to meet demand, can't really tell.  Integrated output mixing valve for anti-scalding.

http://www.heliodyne.com/products_systems/heating/shw_module.html


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## jebatty (Oct 13, 2011)

ew has the link on the module. I didn't do this install and have not yet had a chance to explore the Froling, but very excited to do so.

Yes, more insulation will be needed, or otherwise this can be the staff sauna. 

DP is an environmental learning center, serving children, families and adults; seminars, day camps, multi-day camps, etc., focusing on a wide range of environmental learning opportunities. Deep Portage


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## jebatty (Oct 20, 2011)

I completed my second morning of operating the Froling. Although I have a penchant for hard data on everything, this report will be more experiential than data based. In short, this boiler is really "hot." It will take me more time to learn how to maximize the Froling, but that might not be necessary, as it appears to think quite smartly on its own.

Before my operations, staff at DP was experiencing some "slumber" (idle) operation, which the manual indicates should be avoided. The Froling is to be fired only when storage has capacity to absorb the entire wood load, assuming no system demand. My thought is that the slumber came from over-loading when storage would max out before the wood load burned out. Also, system demand was pretty low during these staff burns. 

My initial loads both mornings were about 1/3 of the firebox, and adding some wood during mid-burns. The firebox is big compared to my Tarm. I had the boiler set at 80C maximum the first morning. The Froling does an excellent job of varying output based on boiler temp, which means that as boiler temp approached 80C the induced draft fan would slow down to lower the output, then speed up as temp dropped. Perhaps it "thinks" and puts together a demand scenario and modulates accordingly, but I don't know that. Operation was excellent, no slumber. I set 85C as boiler maximum this morning, and operation remained excellent, no slumber.

Clearly my initial loads could have been more than 1/3 full. System demand was higher these last two mornings than staff experienced days ago, with early morniong outdoor temps during my burns in the mid to high 20'sF. 

Fire starts are effortless. The Garn has been the easiest boiler to start in my past experience (although I never would say that the Tarm is not easy), and the Froling has to be as easy as the Garn. Mid-burn reloads are effortless and smoke roll-out free. Open the outer door, the induced draft fan goes on "high," open the firebox door, add wood, close, fan slows down, and done. 

I don't think it will take very long to learn how much wood to load based on remaining storage capacity, which the Froling tells you on its display panel. And I will add a variety of sensors when I have time and then I can a data based report, although it might be early winter before that will happen.

The DP goal is to eliminate use of its propane hot air furnaces by use of the Froling, as well as greatly reduce electric use for DHW. The ability to achieve this goal will be demonstrated as the heating season progresses. Propane remains available for backup or supplement, if needed.


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## jebatty (Oct 21, 2013)

It's taken a long time to get to this update, and soon I hope to have hard data available. The install followed the plumbing Sketch A. 1) When the boiler is not operating, the load pulls from top of storage and returns cooler water to bottom of storage - operation as expected. 2) When the boiler is operating and no load, the boiler supplies top of storage and returns from cool water at bottom of storage - operation as expected. 3) But when the boiler was operating and there was a load, a major problem developed. Since all water leaving each of the tank and the boiler also must return to each, the result was that warm/hot load return water was being returned to the boiler and in this installation the result was boiler idling even though much cooler water was available from bottom of storage. If cool return water had been pulled from bottom of storage, the delta-T likely would have been sufficient to prevent or greatly reduce idling.

This problem also relates to the loading unit spec'd with the Froling and the demands of this particular system. The loading unit specs show maximum flow rate of about 12 gpm, but acutal flow rate is not known and based on the problem, actual flow rate is believed to be an unknown amount less than 12 gpm.  The Froling output is rated at 170,000 btuh. Assuming actual flow rate of 12 gpm, at about delta-T >= 28, the maximum Froling output is handled by the loading unit (28 x 12 x 500 = 168,000). But at delta-T < 28, the Froling output exceeds the btu's that the loading unit can move. This normally may not not be an issue with some care in fueling the Froling, but in this particular install, due to warm/hot system return water to the Froling, delta-T appears to have been commonly less than 28F, and therefore idling was the result, even though storage had lower temperature water available to absorb the excess btu's.

The solution which was implemented last week is shown in Sketch B. This solution was possible because the 1650 storage tank had 3 extra 1" ports available. The boiler now supplies only to top of storage and the load draws only from top of storage. The return to the boiler now is only from bottom of storage (coolest water) and the return from the system via dip tubes now is to about the mid-point of storage (because system return still is warm/hot) to avoid mixing with the coolest storage water. Delta-T to the boiler now is at the maximum possible in this system.

Early indications are that a much improved system is the result. The Froling coasts easily to its set output of 80-85C,  and decreases or increases the induced draft to maintain the optimum burn rate. With return water now from the bottom of storage, no idling is occurring. There still is more burn testing to be done, and I am data logging the following temps: boiler supply, boiler return, system supply, system return, and the tank with sensors near the top, at the middle and at the bottom of the tank.


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## __dan (Oct 21, 2013)

Thank You for posting this. It is something I had been giving a lot of thought to.

In my own arrangement I wanted to prioritize cold start performance. With cold storage and the burner firing, heat to the load and not storage.

I was considering some way to have stratification and the weight of the tank water to work in auto, so when return comes back a lot warmer, the heavier colder water in the storage tank should now prioritize loading into storage. That would be the elegant solution. The brute force method would be to use electronic controls and pumps for loading and heat scavenging.

In diagram A, the return riser going up creates a heat trap (trapping the cold lower), so in reverse flow when the boiler is firing and loading the storage, the colder water has to first rise then fall into the boiler, prioritizing the other path, the warmer return water has the easier job of just falling into the boiler.

In my plan, the tank is tapped at the bottom, so the weight of the colder water pushes down and out to the boiler when the boiler is firing, tees right at the loading unit with the warmer return water, and ideally the primary secondary would mostly eliminate pumped pressure differentials between the tank and the boiler, so hot water would rise from the boiler to the header for availability to the loads, return water would mix at the loading unit and hopefully as the return got warmer the colder storage water would get increased priority from the weight of the colder water pushing down and out.

It's all theoretical now as the taps for it are in but the tank is not. And my priority is slightly different. Maximize cold start performance, ignore the storage until the return water comes back a lot warmer, satisfy demand with the least quantity of fuel and go back to ambient (restart cold), loading the excess to storage. With the boiler off, heat scavenging will be the priority.

Of course there's also a big difference running with 10 kw of load compared to 60 kw of load.

I thank you again because it's something that needs more thought, for standardized implementations to become routine. Returning of the warmer return water to the middle of the tank is a keen insight.


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## ewdudley (Oct 22, 2013)

If return from system is warmer than bottom of storage, where did the cool water in bottom of storage come from?

It comes from system return after storage has been mixed by excess system flow after the end of the previous burn.

Another approach would be to control system flow such that system return is always at the minimum temperature consistent with satisfying load.


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## jebatty (Oct 22, 2013)

> Another approach would be to control system flow such that system return is always at the minimum temperature consistent with satisfying load.



This would be a very desirable result. A difficulty is dealing with an installed system and the expense of a change-over.

Later today I will post a graph showing the first data collection, and that will show system return temperature. The system drawing on the tank/Froling includes: 1) three zones supplied by a single 15-58 circ on Lo for two bedrooms plus a hallway; 2) two water to air coil units in the plenums of two LP furnaces (LP is “off”) each served by a separate 15-58 circ on Hi; and 3) a Heliodyne water/water hx unit served by a 15-58 on Lo to charge a dhw tank. The boiler loading unit is an LK 810 with an integral 15-58 circ on Hi. These all are as originally installed.
Any or all of these may have been active from time to time during the period that will be shown by the graph.


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## jebatty (Oct 22, 2013)

The graphs show my first data collection since the plumbing change. I started the Froling with the first wood load at about 6:30 am and staff at DP tended the boiler thereafter. During the entire operation shown, the following demands would have been active according to calls for heat: 1) three zones supplied by a single circ for two bedrooms plus a hallway; 2) two water to air coil units in the plenums of two LP furnaces (LP is “off”); and 3) a heliodyne solar water/water hx unit to charge a dhw tank. Each is served by separate 15-58 circs, 1) and 3) on Lo and 2) on Hi (2 circs). The boiler loading unit is an LK 810 with an integral 15-58 circ on Hi. These all are as originally installed.



> In my own arrangement I wanted to prioritize cold start performance. With cold storage and the burner firing, heat to the load and not storage.



The second graph shows that boiler supply to the top of the tank does not result in the same hot temperature water to system supply. While the temperature of the tank top rises rapidly, As does system supply temperature, the system supply temperature remains less than the boiler supply temperature. It is apparent that some mixing is resulting as hot water is supplied to the tank and as system return water is injected into the middle of the tank, and stratification, while good, likely could be improved by a different plumbing design.



> I was considering some way to have stratification and the weight of the tank water to work in auto, so when return comes back a lot warmer, the heavier colder water in the storage tank should now prioritize loading into storage.



I’m not sure of the physics of your operational theory. Pressure is equal throughout the system. While stratification depends on density, I don’t think that somehow the weight of the water provides an “auto” operation, other than enhancing the stratification process.



> In diagram A, the return riser going up creates a heat trap (trapping the cold lower), so in reverse flow when the boiler is firing and loading the storage, the colder water has to first rise then fall into the boiler, prioritizing the other path, the warmer return water has the easier job of just falling into the boiler.



For me this relates to the extent of mixing and impact on stratification during a load or discharge process.



> Returning of the warmer return water to the middle of the tank is a keen insight.



Thank you, but there have been a number of posts dealing with improved methods of handling warm return water to maximize stratifcation and to make the hottest water always available to the system and the coldest water available to the boiler return to maximize delta-T and boiler hx performance. Ideally, warm system return water would be injected into the tank at various points, depending on the temperature of the return water and the temperature of the stratified tank water. Injection at a mid-point seemed to make the most sense in the DP application and multiple injection points involve more complicated controls and plumbing.

Some other initial observations, and analysis by others is welcome.

1) The first graph shows pretty good stratification occurring within the tank. The objective of  making sure that coldest water was available to boiler return has been substantially achieved, while also achieving the objective of making hot  water available to the system.

2) During the period of operation covered by the graph, outside temperatures ranged between about 28-40F. I know that the Froling was not being loaded with wood to achieve maximum output. My first wood load was about a 2/3 loading of the firebox, and I have good reason to assume that subsequent loading were likely to somewhat less than ½ of the firebox. Even with this loading the Froling easily handled all system demands and continued to charge the tank. The building being served is 6000 sq feet, 3 levels, and is a 1970's building, poorly insulated.

3) I’m not sure what is occurring during the two sharp downward spikes and quick recovery of the boiler supply temperatures. My initial thought is that some bridging might be occurring in the Froling burn process.

4) The graph does not provide data to indicate whether or not any idling occurred during the burn process. I was present during the first 1-2 hours of operation, boiler supply temperature was relatively constant, the induced draft fan was in continuous operation,  was not noticeably modulating, and no idling was occurring during that time. At a later point I will add a sensor to monitor and log flue temperature, and that may provide more useful data to show the operational characteristics of the Froling, including idle periods which I think should be evidence by episodes of reduced flue temperature.

5) When weather gets much colder and the Froling can be pushed for maximum output over an extended period of time, I will do weighed wood burns and better assess the Froling performance.

6) The Froling is attended largely by inexperienced staff. I am working on wood loading instructions to make it easy for staff to not overload the Froling and cause idling when the tank does not have capacity to absorb the btu’s generated by the wood load. The Froling control has a sensor at about the tank mid-point which shows on the control display. Right now this will be used to indicate when and how much wood should be loaded.

7) I will be adding a display panel with digital panel meters to make it very easy to monitor various aspects of the Froling operation, much like I have done with the Wood Gun E500 and the Garn WHS3200 also in operation at DP and serving the main structures.


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## __dan (Oct 22, 2013)

One thing everyone should really grasp is the awesome power available in an efficient clean burning system to raise 1000 gallons of water up in temp. Normally, 1000 gallons of water would just laugh at any attempt to raise its temp, like a flea biting a dog.

It's really a demonstration of the power of 90% efficient systems that can convert the available heat in cordwood into satisfying demand for large, usually immoveable loads.

I have burned four fires total since the beginning of October, just tempering the slab, and the house is running 69 in the morning, 72 in the afternoon. Have about two years worth of junk to burn in the yard until I really get into the seasoned oak splits. If I had to burn oil to heat the slab I would be waiting for Thanksgiving.


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## BoilerMan (Oct 22, 2013)

__dan said:


> One thing everyone should really grasp is the awesome power available in an efficient clean burning system to raise 1000 gallons of water up in temp. Normally, 1000 gallons of water would just laugh at any attempt to raise its temp, like a flea biting a dog.
> 
> It's really a demonstration of the power of 90% efficient systems that can convert the available heat in cordwood into satisfying demand for large, usually immoveable loads.
> 
> I have burned four fires total since the beginning of October, just tempering the slab, and the house is running 69 in the morning, 72 in the afternoon. Have about two years worth of junk to burn in the yard until I really get into the seasoned oak splits. If I had to burn oil to heat the slab I would be waiting for Thanksgiving.


 I totally understand, but must disagree with this statement. 

You can heat 1000 gal of storage with a 20% solid fueled boiler if you want to, just more wood!  If you are not able to heat the same slab with oil you are undersized or over-pumped in the oil circuit.

Think about a typical statement: "That danged stove heats my shop better than my Miller trailer furnace".  Well that stove is a tire-rim stove welded up with 6011 'farmer's rod' and he puts in a wheelbarrow full of wood twice a day.  His Miller is rated at 60,000 btu.  

Apples to apples says heat from any source at any efficiency will provide the same heat as long as the output is the same.  Think about all of those OWB out there running less than 30% overall efficiency. 

TS


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## maple1 (Oct 22, 2013)

I think you guys are saying the same thing:

More heat from less fuel.


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## __dan (Oct 22, 2013)

Waiting for Thanksgiving means I am too cheap to pay for oil. Just google "cheap" and you'll see my picture. A winter with the slabs is ~ 1.5 tanks oil, maybe 450 gallons if I burned for heat the same way I burn wood. Since I was too cheap, I was burning one tank oil over the winter, 270 gallons. I  have lots more heat now.

I'm burning branches, bark, and splitter debris right now, actually earlier today, the boiler is off and the house is 73.

Try raising the water temp on 1000 gallons of water by burning bark and splitter sweepings. The storage will just laugh. It's a big load to move around.


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## Fred61 (Oct 22, 2013)

cheap? Thrifty?


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## jebatty (Oct 23, 2013)

From Sketch A it is apparent that the entire tank rather quickly will reach an equilibrium minimum temperature equal to system return temperature, and therefore, while the "coldest" water will remain at the bottom of the tank and be available to the boiler return, that "coldest" water will be quite warm and -T may end up in the vicinity of 20F +/-. At that temperature difference, and assuming 12 gpm from the loading unit, only 120,000 btuh can be moved from the boiler, which is well below the Froling capacity. 

One solution to increase -T follows from ewdudley suggestion "to control system flow such that system return is always at the minimum temperature consistent with satisfying load." That I will have to work on. Initially two prime candidates are the 15-58's serving the 3 zones and serving the dhw hx. 

Another solution would be to increase flow through the boiler to the tank, and a higher capacity circulator parallel to the loading unit would do this, and be controlled so that it would run only when tank return water was somewhat greater than 150F, for example. The loading unit's function to maintain boiler return water protection is not needed at this point, and I'm thinking that a relay to switch from the loading unit circulator to the parallel circulator, controlled by the Froling (the Froling would "see" the parallel circ as the loading unit circ), would do this.

Both of these fixes are only good so long as sufficient storage is available to absorb the excess btu's, and the Froling still cannot be loaded with wood when it's output exceeds system demand as the tank moves towards a full charge.

The Froling controls also have a way of dealing with this issue. The Froling modulates its output between 85,000 and 170,000 btuh. With the original design plumbing, this did not solve the idling issue, but a second issue was the Froling idling when the tank still had cold water available to store btu's. I think this may have mislead staff into believing that the Froling could still be loaded with wood because storage was not "hot."

Sketch A shows that the plumbing design changes will eliminate the "cold water available" issue and improve storage capacity, but idling to the extent caused by excess wood loading by staff still will need to be addressed. I think this can be adequately addressed once I add a monitoring panel that clearly shows the temperature of the storage tank and an instruction sheet is provided staff which will indicate how much wood to add based on storage tank temperature. This is the same procedure used for staff when loading the Wood Gun E500 and the Garn WHW3200, and wood over-loading is not an issue with those boilers.


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## Chris Hoskin (Oct 23, 2013)

I'm really loving this thread, of course   Jim, I wonder if you might want to get Fröling's "Vision" software that would allow you to easily monitor and data log most everything you are interested in and view it / save it onto an SD card or a laptop?  Also, you may want to consider adding our Acaso Automix outdoor reset control.  This time of year especially, you will just be sipping off the tank which will maintain better stratification and the lower return temps you are looking for.  One last thing, I am reminded of Piker's install where he was seeing higher than expected/desired return temps - turns out the loading unit pump was moving water too QUICKLY.  So what was happening was that a well defined stream developed in the tank where water was flowing from the supply straight to the return which was screwing up stratification and not doing much mixing either.  I'm not sure that is what is going on here, but it might be worth trying turning the loading unit down a speed.  Looking forward to hearing more.  Chris


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## jebatty (Oct 23, 2013)

Chris, thanks for the input, which I really appreciate. I will talk to DP about the software and outdoor reset, and I will try moving the loading unit circ from Hi to Med.


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## TCaldwell (Oct 23, 2013)

Chris, does the software log combustion parameters such as 02, co2, co, flue temp and damper outputs? If so have you seen any data trends, or sold the software to anybody. It would be interesting to compare with the ones Brian Crawford posted for the effecta boiler.


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## hiker88 (Oct 23, 2013)

I suppose there must be some ghost in the machine factor for every install.

I had to put my circulator pump to high from medium because it was idling at lower than desired return temps.  With the pump on high, and me weighing my wood before the burn, I can heat my 820 gallons of unpressurized storage 85c top, 80c bottom with zero slumber and a set point of 88c.  With over 1100 hours on the unit now, only 21 hours has been in slumber.

I'm sure you will get it dialed in.  I think the hardest part will be the number of different operators. Perhaps there will be a couple interested souls that will take the effort to load and run it properly.

Looking forward to the updates.


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## Chris Hoskin (Oct 24, 2013)

hiker88 those stats are awesome!  Well done.


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## skfire (Oct 24, 2013)

hiker88 said:


> I suppose there must be some ghost in the machine factor for every install.
> 
> I had to put my circulator pump to high from medium because it was idling at lower than desired return temps.  With the pump on high, and me weighing my wood before the burn, I can heat my 820 gallons of unpressurized storage 85c top, 80c bottom with zero slumber and a set point of 88c.  With over 1100 hours on the unit now, only 21 hours has been in slumber.
> 
> ...



Same here, setpoint 87, 845 gallons storage(total), cranking 85top, 80-82 bottom, no slumber with wood loads per volume,(eye balling it at this point)/outside temps/storage status/house temps, Logged in 1164 hrs, 13 hrs slumber. Pump is set at medium speed.

Right on about the operator fluctuations...when wife runs it, I make sure she underloads and get tanks to 85 top 50-60 bottom...playing it safe.

Just cranked it 3 days ago..all good.

Scott


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## mustash29 (Oct 26, 2013)

Chris Hoskin said:


> higher than expected/desired return temps - turns out the loading unit pump was moving water too QUICKLY. So what was happening was that a well defined stream developed in the tank where water was flowing from the supply straight to the return which was screwing up stratification and not doing much mixing either


 
That would be considered "channeling".....yes?

As in when you have high flow through a resin filtration bed (demineralizer, charcoal media, etc) you can cause a channelling / tunneling effect where the flow takes the path of least resistance and moves through the filter media and does not get cleaned / purified correctly.  At my work we have anion / cation resin beds that turn city water into grade A pure water for boiler makeup.  Exccessive flow will cause them to die with low throughput.  They usually break through on high silica before they hit the high conductivity set point.  We now have an RO unit and run the demin beds as polishers.  300 Kgal instead of 30 Kgal throughput before needing a re-generation.

Back to boilers & storage.....besides pumping capacity, what about using a flow diffuser on the tank tappings?  Say you have a 1" pipe from the boiler to the tank.  Why not insert that pipe into the tank, drill that pipe full of holes and "shower" the top of the tank with little jets instead of a 1" stream.  The same could be done with the cold "suction" from the tank to the boiler.

Simple diffuser manifold.  My boilers at work:

- Dearating feed water tank is 12 psi and roughly 290 deg F
- The boiler economizer pre heats that to about 400 - ish
- So 400 ish feedwater at 130 gpm is injected to the bottom of a horizontal steam drum via a 4" by 12 foot long diffuser pipe with lots of 1/2" holes
- Steam drum temps are running about 550 and 1000 psi, this is a saturated system 1/2 water, 1/2 steam with cyclonic and chevron moisture separators on the steam outlet.  That steam is then superheated to 830 deg F.


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## jebatty (Oct 26, 2013)

I doubt "channeling" is occurring. Data 4a and Data 5 graphs show that boiler return water is nearly the same temperature as bottom of tank water. It also seems that if any "channeling" is occurring, it most likely would channel from boiler supply to system supply, and it does not appear that this is occurring due to the difference in temperature between boiler supply and system supply. 

The graphs show pretty good stratification on tank charging although some mixing is occurring because hot boiler supply is greater than hot system supply, and as tank charging progresses bottom of tank temperature is closing to tank top temperature even when tank top temperature is dropping. I still will try slowing down the loading unit circ and data log to see the results. My intuition tells me that the solution will be 1) more care in not overloading the Froling as bottom of tank temperature rises towards the temperature of system return water and 2) working to adjust flows to achieve lower system return temperatures.


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## jebatty (Nov 20, 2013)

More flow tuning to do, but in the meantime I finished and installed the monitoring panel for the Froling. The temps for SS (system supply) and SR (system return) will make it easy to finish the flow tuning.

We will be using the M (middle) of storage temperature as the guide to reload and fire the Froling. Simply stated, for starters, if M is at or below 130F, load to bottom of firebox door opening. This will be about 50-80 lbs of wood (aspen/oak), or 65 lbs average, based on the wood mix; or about 390,000 btu's for the average mix of wood. Instructions will be to load only when low coals or fire out, and always a full load to the bottom of the firebox door.

Both the reload temp and the amount of the wood load will be revised based on demand experience and outdoor weather temp, may add reset later. This will allow the most inexperienced staff to load the Froling and allow it to burn with maximum output with no idling to end of burn because there always will be sufficient storage capacity to take the output, even if there is little system demand. The storage tank is 1650 gallons.

I'm just about at the point of shutting down the system and operating only the Froling to charge storage to better measure actual output and efficiency based on 6050 btu/lb of wood, assumed 20% MC. The storage tank is pretty well insulated, but there still is quite a bit of heat loss to the Froling/storage tank building, so an efficiency determination will be skewed downward by ambient heat loss.


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## maple1 (Nov 20, 2013)

Wondering on your temp guages - those look like the same Ebay ones from the far east that I have, but I think I see a bunch of Cat5 running into the box? Did you adapt/modify the 'stock' probe wiring to Cat5?

And do you have a link for your stage guage/probe? I'd still like to have digital probes in my stack & my secondary chamber - but I still haven't gotten around to finishing up all the other probes I have yet to put in.


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## jebatty (Nov 20, 2013)

The temp gauges use DS18b20 sensors. Each gauge needs it own direct wire to the gauge. I used Cat5e: orange/ow to one gauge; brown/bw to another gauge, blue/bw to a 3rd gauge; and combined green/gw for a common ground. More cable for more gauges.

On eBay search for "ds18b20 temperature meter" for the temp gauges. Most if not all of these come with the sensor. Different colors are available.

The stack gauge is K-type with probe:
http://stores.ebay.com/Procon-Products?_trksid=p4340.l2563
http://www.ebay.com/bhp/type-k-thermocouple-high-temperature

You can see a silver cable for the K-type, not modified for Cat5e.

For a power supply I used a 12vdc walwart, but I am going to replace it with about an 18vdc supply. The ds18b20 gauges are plenty bright on 12vdc, but my K-type gauge is rated at 24vdc, works on 12vdc but it is not very bright.


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## muncybob (Nov 20, 2013)

I'm considering an led display for my basement boiler...is there a way to have this info wirelessly sent to a monitor of some sort in a different part of the building? I'm not talking to a phone or pc but to a dedicated wireless display.


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## maple1 (Nov 20, 2013)

jebatty said:


> The temp gauges use DS18b20 sensors. Each gauge needs it own direct wire to the gauge. I used Cat5e: orange/ow to one gauge; brown/bw to another gauge, blue/bw to a 3rd gauge; and combined green/gw for a common ground. More cable for more gauges.
> 
> On eBay search for "ds18b20 temperature meter" for the temp gauges. Most if not all of these come with the sensor. Different colors are available.


 
Sounds & looks like we've got the same guages & sensors. So you needed to splice the Cat5 into the sensor leads, between the sensor tip & the plug on the other end? Is there a limit as to how long you could make the leads? Not sure I'm up to splicing that tiny stuff.

Thanks for the other info - I don't know if I will ever be 'finished'.


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## jebatty (Nov 20, 2013)

Yes, have to cut the sensor cable, strip and splice. Tedious and I soldered all splices, then shrink wrap for insulation. There is a limit I'm sure, but I have had success up to about 30 feet. What does "finished" mean? ha ha.


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## jebatty (Dec 14, 2013)

Learned something yesterday about the Froling. Although the control appears to be programmable for different output levels, that is only functional with an adjustable loading unit which I have not seen to be available in the US. Short answer is that output is at the maximum 170,000 Btuh rate regardless of the control setting. I wanted to make sure that the Froling was set for maximum output before proceeding further. This is a good result for DP because the building being served needs full output, and because DP has adequate storage, there is no need for a reduced output setting anyway.

Also good news on staff reports during our recent cold spell when temps got down to -29F at night and didn't rise above 0F during the day. The Froling met all heat and dhw needs without any need to switch to LP to meet demand or comfort levels. Supply water to the system during the highest demand periods at this time fell to a little over 130F, but no complaints about the building not being warm enough or insufficient dhw. I noticed middle of tank temp at 108F, and bottom of tank was about the same, so boiler supply to top of tank was remaining stratified to provide hotter water to the system.

With bottom of tank return to boiler at about 108F during this cold spell, the loading unit was mixing supply with return to provide required return hot water protection, so full boiler output was not available to the system. Output to the tank was in the 160-165F range, but flow from the tank to system was at higher gpm than boiler supply gpm to the tank, cooler water in the tank was being mixed with hot boiler supply to provide demand gpm, and therefore supply temperature to system was lower than boiler output to the tank. EDIT

And yesterday when daytime temp stayed at a nearly constant 0F, I observed that the Froling not only was meeting demand but storage tank temperatures were rising.

I didn't have time during the cold spell to spend a night with the Froling to do weighed wood burns, data log, and make any determinations of output, efficiency, etc. I want to be able to do that soon if the weather cooperates with my schedule. Regardless, it appears to me that the Froling is now operating as its design permits, and importantly DP also is getting the heat it needs. The data and analysis will be an add-on benefit for educational and informational purposes.


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## flyingcow (Dec 14, 2013)

jebatty, how ,any different brands of wood burners have you operated/owned/oversee? seems to me a few more brands for you to play with and you're the consumer reports of gasser's? BTW, a good part of your post here has been a bit over my head, but interesting and good reading. You've got me wanting to put my Innova down in my truck garage and replace with a Froling at the house.


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## ewdudley (Dec 14, 2013)

jebatty said:


> With bottom of tank return to boiler at about 108F during this cold spell, the loading unit was mixing supply with return to provide required return hot water protection, so full boiler output was not available to the system.


I don't see where any of the heat produced by the boiler could go except to the system.

Boiler not getting hotter or cooler, so zero heat flow to boiler.

Storage not getting hotter, so zero positive heat flow to storage.

All heat generated by boiler must be going to system.

170,000 btu per hour of heat generated by boiler.

5.96 gpm of 108 degF water coming in from storage, 5.96 gpm of 165 degF going out to  storage.

No less than 15.45 gpm of 130 degF going out to system, no less than 15.45 gpm of 108 degF returning from system.


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## jebatty (Dec 14, 2013)

Four brands: Tarm Solo Plus 40 - 2007, the Froling now in its 3rd heating season, and a Garn WHS3200 and Wood Gun E500 starting in 2009 if I remember correctly. If I had to replace my Tarm, I would consider a Froling or similar based on info then available. On the other hand, my Tarm is very simple to operate, the control system is simple and easily modified/supplemented, and it has been trouble free since installed, once I learned how to operate it. When the time comes, the choice will be challenging, that is if simple, quality boilers then are available.

Thanks for the compliment. I had no prior experience in HVAC, and only personal domestic water/drain plumbing experience before 2007. I've been given the title of "engineer" at DP, not really merited, but the educational and learning journey has been a ball. I still make mistakes and/or fail to analyze things correctly, but that's been my learning curve.


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## jebatty (Dec 14, 2013)

ewdudley said:


> I don't see where any of the heat produced by the boiler could go except to the system.



I am glad that you take the time to review my posts. I think you are correct. My example, which really is the same as yours, which leads me to the conclusion that you are correct: The Froling/loading unit with a single 15-58 specs 12 gpm maximum. If boiler output is 165F, if system return water is 108F, then delta-T = 57, and if boiler is producing rated output of 170,000 Btuh, then it follows that 170,000 / 57 / 500 = 5.96 gpm flow rate to the tank/system; which then also means that about 6 gpm is being recirculated through the boiler. Do I have it right?

You have stated in the past that all "heat produced by the boiler must go to the system" and I need to indelibly etch this in my brain. Thanks.

Your edit also is very helpful, and that's where I was going next in this reply, but no longer need to do so. Thanks again. I am editing my prior post to delete the erroneous statement.


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## jebatty (Dec 14, 2013)

ewd -- I don't think I ever will be able to reach the point where storage temp is in equilibrium so that i can calculate exactly what the flow is to the system, especially because 5 - 15-58 draw from the system in various series/parallel configurations, and none to one or more may be "on" at any point in time.


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## ewdudley (Dec 14, 2013)

jebatty said:


> The Froling/loading unit with a single 15-58 specs 12 gpm maximum. If boiler output is 165F, if system return water is 108F, then delta-T = 57, and if boiler is producing rated output of 170,000 Btuh, then it follows that 170,000 / 57 / 500 = 5.96 gpm flow rate to the tank/system; which then also means that about 6 gpm is being recirculated through the boiler. Do I have it right?



We've got two unknowns, actual boiler btu per hour, and actual 15-58 gpm. 
Assuming BTU per hour of 170000 we get one answer:

Calc GPM:
      7.64 GPMRecirc
     5.96 GPMStorageNet
    13.60 GPM1558
170000.00 BTU


And assuming 15-58 gpm of 12 we get another:

Calc BTU:
       6.74 GPMRecirc
     5.26 GPMStorageNet
    12.00 GPM1558
150000.00 BTU


```
use strict;

my $TBoilerSup;
my $TBoilerRet;
my $TStorageRet;
my $BTU;
my $GPM1558;
my $TBoilerDelta;
my $TStorageDelta;
my $TMixDelta;
my $GPMStorageNet;
my $GPMRecirc;

sub calc_gpm {
   $GPMStorageNet = $BTU / ($TStorageDelta * 500);
   $GPMRecirc = ($GPMStorageNet * $TMixDelta) / ($TBoilerDelta);
   $GPM1558 = $GPMStorageNet + $GPMRecirc;
}

sub calc_btu {
   $GPMRecirc = ($GPM1558 * $TMixDelta) / $TStorageDelta;
   $GPMStorageNet = $GPM1558 - $GPMRecirc;
   $BTU = $GPMStorageNet * $TStorageDelta * 500;
}

sub pr {
   printf("%9.2f GPMRecirc\n", $GPMRecirc);
   printf("%9.2f GPMStorageNet\n", $GPMStorageNet);
   printf("%9.2f GPM1558\n", $GPM1558);
   printf("%9.2f BTU\n", $BTU);
   printf("\n");
}

$TBoilerSup = 165;
$TBoilerRet = 140;
$TStorageRet = 108;
$TBoilerDelta = $TBoilerSup - $TBoilerRet;
$TStorageDelta = $TBoilerSup - $TStorageRet;
$TMixDelta = $TBoilerRet - $TStorageRet;

$BTU = 170000;
calc_gpm();
printf("Calc GPM:\n");
pr();

$GPM1558 = 12;
calc_btu();
printf("Calc BTU:\n");
pr();
```


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## jebatty (Dec 14, 2013)

I think the more objective variable is the gpm. I have used 12 gpm but the spec is not exactly 12 and an adjustment can be made for the actual spec. I also can do a head calc on the plumbing to estimate actual gpm. 

Btuh output may be a constantly moving variable, depending on the stage of the burn, moisture content, etc., although the Froling appears to seek a maximum available output through the lamda control, varying the speed of the draft inducer, and varying the air mixture in the firebox and gasification chamber.


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## ewdudley (Dec 14, 2013)

jebatty said:


> I think the more objective variable is the gpm.


So with boiler operating conditions not really out of the ordinary and a reasonably conservative 15-58 flow estimate of 12 gpm, the unit is supplying a solid 150,000 btu per hour net for real.  Around here, that's about $4.50 an hour in heating oil not burned, not bad!


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## jebatty (Dec 14, 2013)

Really appreciate the input. Thanks!


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## jebatty (Jan 2, 2014)

Getting close to a full report on the Froling. Spent the night with her last night, low of -27F, calm wind. Although the goal was not to determine whether the Froling could satisfy the full demand of the 6000 sq ft Interpretive Center building that it is heating, plus dhw, the Froling in fact did that, and it also slowly added to storage btu's. 

I want to do one more night after the Froling has been fully cleaned, which should provide maximum output results. The burn last night was after a number of days of full-time, full output, 24-7 operation, and I'm guessing that flue temp probably was somewhat high and available output was somewhat low as a result. Anyway, a 2nd burn will determine that. We're headed for another very cold spell this weekend, and I hope that can be another night out with a sweet, hot friend.


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