Wood Boiler W/Storage Control Logic and Plumbing Diagram... How'd I do?

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

TuckerTerra2000

New Member
Mar 18, 2021
17
Maine
This is the theory of operation I have come up with for my diagram. I am looking for you seasoned professionals to review it and tell me how it will work.
The storage tank is 500 gallons pressurized.

Wood Boiler W/Storage Control Logic and Plumbing Diagram... How'd I do?


I will be programing a PLC with thermocouple at the locations given in the diagram. I am an electrician, not a heating tech. Let me know if my diagram and controls seem they will work correctly.

Theory of operation: If the wood boiler is at temp and house isn’t calling for heat, send the heat to the tank. If the wood boiler is at temp and the house calls for heat, send the heat to the load. If the house calls for heat the tank is at temp but wood boiler isn’t, send heat from the tank to the load (this will depend on whether it is a radiant (low temp) call or a DHW (high temp) call. If the wood boiler or the storage is not hot enough the oil boiler will fire.

  • -If the temperature at location “A” is above 100 degrees and there is at least a 10 degree difference between Location A and location B the circulator at location B turns on and the valve at location A opens
  • If the boiler return (Location B) is over 150 and the boiler output (location A) is hotter than Location D, and the house is NOT calling for heat the tank valve at location C opens.
  • If the boiler return (Location B) is over 160 and the boiler output (location A) is hotter than Location B and the house calls for heat, the valve at location C closes, the valve at location E opens, and circulator at location F energizes. (all valves/ circulators resume back to operation as in step #3)
  • If the boiler return (Location B) is NOT over 160 or the boiler output (location A) is NOT hotter than location B and the house calls for heat:
  • Valve at location A closes and Circulator at location B deenergizes. This holds true until the temperature at location A exceeds 160.
  • If zone calling for heat is radiant and the tank temperature at location H is above 100 the valves at location C & E opens, and the valve at location G closes. If the temp is not above 100 the valve at location G opens, Oil boiler is fired, and valve E is closed.
  • If zone calling for heat is DHW and the tank at location H is above 140 the valves at location C & E, and the valve at location G closes. If the temp is not above 100 the valve at location G opens, Oil boiler is fired, and valve E is closed.
  • If the tank rises above 200 it forces valves at locations A, C and E open and energizes circulators at location B. It also forces on the basement radiant zone which is 2600 of slab radiant. If the tank doesn’t drop below 200 for 5 minutes it triggers a trouble alarm output on my security system



    here are more ways of saying the same theory of operation
    Anytime the oil boiler is operating the valve at location G is open. Valve at location E is closed.

Anytime the tank is feeding the heat load Valves at location G and A are closed and valve at location E is open.

Anytime the Wood Boiler is feeding the heat load the valves at location G and C are closed and valve A is open.

I will have a toggle switch on the control box that will either:

  • In normal position/operation Connect the zone controller end switch with the PLC input and the oil boiler control will be operated via a relay controlled by a PLC output.
  • In Emergency Bypass position it will allow all function of the PLC to perform normally EXCEPT: It connects the zone controller end switch directly with the oil boiler control. This will allow the oil boiler to operate as a complete standalone system if there are any issues with controls/components.
I will have a digital readout of tank temp at location H and LED lights that will illuminate if each valve/ circulator is active.



I am relying on an automatic standby generator for power loss issues.
 
Looks complicated
I was told you should be pumping away from your pressure tank.
My designer has my backup oil boiler tied into the main line with close spaced tees.
Wish i could use a computer to make that nice diagrams i see here.
 
Looks complicated
I was told you should be pumping away from your pressure tank.
My designer has my backup oil boiler tied into the main line with close spaced tees.
Wish i could use a computer to make that nice diagrams i see here.
Here is a simpler diagram. The other one was a little more complicated than it needed to be, and looked confusing. Not to mention the heat return line was done in a different fashion. This makes more sense to me...

Wood Boiler W/Storage Control Logic and Plumbing Diagram... How'd I do?
 
It would be easier if you would just put up the original Tarm schematic first and then tell us what you are changing.
Don't just copy and past "stuff" created by others. At least make a reference to them.
I agree on location of exp tank.
 
It would be easier if you would just put up the original Tarm schematic first and then tell us what you are changing.
Don't just copy and past "stuff" created by others. At least make a reference to them.
I agree on location of exp tank.

No intension to "Plagerize" here. I am just trying to make a system work for what I am trying to do. I have tried explaining before but without a visual reference it seems a lot of people do not understand.

I was told after that I need the exp tank on the cold return....?

I have updated the diagram to one that is less confusing and fixed some issues I had on the first one.

Wood Boiler W/Storage Control Logic and Plumbing Diagram... How'd I do?
 
My expansion tanks are all on the hot side with the pumps pumping away from them.
I run a heat exchanger, my wood boiler and storage is water and have the Backup oil boiler, underground and house is glycol.
 
The system looks overly complicated. My system uses the oil boiler to control the heat and hot water and the boiler is kept warm via an injection pump controller and pump piped into the return of the oil boiler. Wood boiler and associated circuits have flow meters so they only get the flow they need and the excess goes into storage. The only electronic component is the injection pump controller which is a Tek-Mar off the shelf unit.

1666747200430.png

Froling S3 Turbo 50, 880 gallons of storage.
 
My system uses a PLC (EASYIO FG32+) and it appears complicated but it’s been one of the most reliable and easy to operate systems after over 6+ years of operation. Just load wood and start the boiler and the system adjusts accordingly.
 
Not sure what you are using for software to generate the drawings but looks nice.
 
This is the theory of operation I have come up with for my diagram. I am looking for you seasoned professionals to review it and tell me how it will work.
The storage tank is 500 gallons pressurized.

View attachment 300814

I will be programing a PLC with thermocouple at the locations given in the diagram. I am an electrician, not a heating tech. Let me know if my diagram and controls seem they will work correctly.

Theory of operation: If the wood boiler is at temp and house isn’t calling for heat, send the heat to the tank. If the wood boiler is at temp and the house calls for heat, send the heat to the load. If the house calls for heat the tank is at temp but wood boiler isn’t, send heat from the tank to the load (this will depend on whether it is a radiant (low temp) call or a DHW (high temp) call. If the wood boiler or the storage is not hot enough the oil boiler will fire.

  • -If the temperature at location “A” is above 100 degrees and there is at least a 10 degree difference between Location A and location B the circulator at location B turns on and the valve at location A opens
  • If the boiler return (Location B) is over 150 and the boiler output (location A) is hotter than Location D, and the house is NOT calling for heat the tank valve at location C opens.
  • If the boiler return (Location B) is over 160 and the boiler output (location A) is hotter than Location B and the house calls for heat, the valve at location C closes, the valve at location E opens, and circulator at location F energizes. (all valves/ circulators resume back to operation as in step #3)
  • If the boiler return (Location B) is NOT over 160 or the boiler output (location A) is NOT hotter than location B and the house calls for heat:
  • Valve at location A closes and Circulator at location B deenergizes. This holds true until the temperature at location A exceeds 160.
  • If zone calling for heat is radiant and the tank temperature at location H is above 100 the valves at location C & E opens, and the valve at location G closes. If the temp is not above 100 the valve at location G opens, Oil boiler is fired, and valve E is closed.
  • If zone calling for heat is DHW and the tank at location H is above 140 the valves at location C & E, and the valve at location G closes. If the temp is not above 100 the valve at location G opens, Oil boiler is fired, and valve E is closed.
  • If the tank rises above 200 it forces valves at locations A, C and E open and energizes circulators at location B. It also forces on the basement radiant zone which is 2600 of slab radiant. If the tank doesn’t drop below 200 for 5 minutes it triggers a trouble alarm output on my security system



    here are more ways of saying the same theory of operation
    Anytime the oil boiler is operating the valve at location G is open. Valve at location E is closed.

Anytime the tank is feeding the heat load Valves at location G and A are closed and valve at location E is open.

Anytime the Wood Boiler is feeding the heat load the valves at location G and C are closed and valve A is open.

I will have a toggle switch on the control box that will either:

  • In normal position/operation Connect the zone controller end switch with the PLC input and the oil boiler control will be operated via a relay controlled by a PLC output.
  • In Emergency Bypass position it will allow all function of the PLC to perform normally EXCEPT: It connects the zone controller end switch directly with the oil boiler control. This will allow the oil boiler to operate as a complete standalone system if there are any issues with controls/components.
I will have a digital readout of tank temp at location H and LED lights that will illuminate if each valve/ circulator is active.



I am relying on an automatic standby generator for power loss issues.
That seems overly complicated. Why would you use so much logic and motorized valves in a system? I have a Froling FHG and installed my own Tarm BLT controller. The two things in your schematic that is different than mine is the use of valves (A) and (C). They do not exist in my system. I dont know why you would need those motorized valves when you have the thermostatic valves at (6) and (7).

Do you have a specific question?

In a nut shell, the zone demands get preference for heat when the boiler is firing. The motor operated valve (E) is like the gate keeper. When the boiler is firing and there are no zone demand its closed, the flow can only go to the storage tank. Once a demand is created, the MOV allows flow to the zone(s). The other valve (6), is thermostatic and changes state at about 150F, no controls needed, this is passive. Its thermal protection so your returning water is not too cold. Valve (7) is also thermostatic also and doesn't allow water back to the tank/boiler until it's dropped <160F. That allows the water in the zone to be circulated until it's given up its heat. On the FHG, the circulator at the boiler (B) turns on by the boiler control once the water jacket reaches 140F.

If it helps, you can search the threads I've created and find my build thread. I re-drew the piping schematic for my system to help me understand how I would tie together my existing piping and what Froling is suggesting.
 
Last edited:
WOW!
I finally went there, the rabbit hole that is the " Boiler room."
It started with a google search about what exactly was a Froling FHG turbo 3000 wood gasification boiler which seems old as the threads were back in 2010. I read about the guy in CO with the electric baseboard with the $70,000 estimate install who found himself freezing along with his wife in January because his installer had knee surgery. He built a separate room attached to his house because of the rock at his location. Those FB marketplace ad's do it every time I see something I'm not familiar with.This time it was this beast!
309903041_6024157987645715_658804865322099570_n.jpg

Froling FHG turbo 3000 wood gasification boiler. Unit alone without 3 tanks of storage was over $15,000 new. Unit works perfect and heats over 3,000 sf with 800 gallons of thermal storage. Can fully adjust all settings to personal preferences or application, this isn’t your average “wood boiler”. Only reason for selling is I converted to propane because I’m not at location 24-7 to feed the boiler. It is still installed, will remove for buyer.​

313027199_5668343866586088_3485209983826740134_n.jpg
 
Last edited:
  • Like
Reactions: sloeffle
Looks like a great system, I like the "rolling safe" option ;). I would suggest that you put this in the for sale section with more details on the models and sizes. For Sale should be in the thread title. Also you should define what goes and what stays. Unfortunately it is probably going to take a while to sell. I have a spare Tarm Solo Plus60 in the garage minus storage so its not for me unless you get to the point of parting the system out, but for someone looking to get a first class system, its a great start. A big plus is Tarm Biomass in Orford NH most likely imported it and has a great rep for supporting their products.

I know of various approaches to selling stuff on line about neither the seller or buyer naming the initial price but someone has to do it and sad to say no matter how good it is the market is thin and anyone grabbing it needs serious equipment to remove and transport it. It may be worth listing how easy or hard the access is. If you could support getting it out of the basement into the back of truck or trailer that will increase the number of buyers. The other issue is that there are few if any competent installers out there so anyone buying it is on their own to fit it into their system unless they just duplicate your install. That further reduces the real demand. There may be a lot of tire kickers out there and your goal should be to screen them out early unless you have infinite time and patience.

That is how I got my Tarm, the owner was clueless about the unit and didnt realize that not everyone is capable of moving a 1200 pound boiler across a basement and then up and out of a bulkhead without trashing things. She wanted close to the original retail price, but I paid $1000 bucks as she was a motivated seller.
 
Looks like a great system, I like the "rolling safe" option ;). I would suggest that you put this in the for sale section with more details on the models and sizes. For Sale should be in the thread title.
Ya, $11.000
sorry for any confusion. It's not mine. I saw it for sale and it led me back to here the boiler room. Actually that's not entirely true I came straight here as I know a search would have inevitably taken me here. First time checking out this portion of the forum and I read threads for a few hours.

I would have attached my thoughts there but they were all around 2010 and closed. I saw this thread and it was about the same boiler so I just wanted to comment what a great forum this is. Yesterday I had no clue what a gasification boiler was and now I almost feel like there's one in the basement!:eek:
 
Ya, $11.000
sorry for any confusion. It's not mine. I saw it for sale and it led me back to here the boiler room. Actually that's not entirely true I came straight here as I know a search would have inevitably taken me here. First time checking out this portion of the forum and I read threads for a few hours.

I would have attached my thoughts there but they were all around 2010 and closed. I saw this thread and it was about the same boiler so I just wanted to comment what a great forum this is. Yesterday I had no clue what a gasification boiler was and now I almost feel like there's one in the basement!:eek:
So I'm confused...are you buying, or selling?
 
So I'm confused...are you buying, or selling?
Neither, I'm commenting.
"I saw this thread and it was about the same boiler so I just wanted to comment what a great forum this is." With pictures!
 
Last edited:
Neither, I'm commenting.
"I saw this thread and it was about the same boiler so I just wanted to comment what a great forum this is." With pictures!
Funny you bring this up because I just saw this boiler listed for sale today and I had to chuckle about the price also. That boiler was about $10k new. I know because I bought one new but, heavily discounted. Nice system, be a shame to dismantle it.
 
  • Like
Reactions: Tylervt
I agree with above posters, all the dwgs you displayed are over complicated IMO. This is the system i installed last year using a Froling S3 Turbo heating 3600 sq ft and doing it with ease. Storage is 2 x 250 gal tanks piped in series, couldnt fit a single tank in my boiler room nor could i use more storage.

System consists of 5 zones supplied with one circulator. The system also supplies all DHW using a Turbomax instantaneous indirect water heater.

Below is the schematic as well as the 3D CAD dwg i did for the job. If you have any questions please drop me a line and ill be sure to help. Im no heating expert but i did 5 years research here with help and advice from many on this forum and willing to pass on some of what i learned. With that said i am a instrumentation and controls tech with 25 years experience so that no doubt helped.

I can tell you that this design is now proven and works perfect in every way, i was lucky enough to get it right on first attempt. If i had one wish it would be for more storage, the S3 can pump out some serious BTU's and i can easily drive the boiler into slumber (idle) on a full load after heating house on a cold morning and also bringing storage to 185 deg.
 

Attachments

  • Boiler piping 2-Model.pdf
    365.5 KB · Views: 178
  • Boiler 3D Model Rev 3-Model.pdf
    155.6 KB · Views: 177