Boiler controls

[Hilltop366]

Thinking about this...if things are in danger of freezing you would want the boiler circulator to run full time regardless of boiler temp and have a different way to regulate the house temperature.

One way to do this is to have a continuous loop from boiler storage tank to home, you put tees in the line for your radiator and after the first tee (hot side tee) put a reducer to make the main line smaller and a valve on the return side of the rad.

The most basic would be to have a valve that you open or close the amount needed for the heat required a better set up would be a non electric zone valve.

Zone valve open and water flows through loop and rad(s)
Zone valve closed all water flows through loop only.

With this there will be no freezing and a even controlled temp in home.

I run a apartment building with this kind of setup (except we use motorized zone valves), it has three loops and 23 zones.

[mike_belben]

the easiest thing for me is to make the flame output constant.. well..  manually variable.  oh its sunny today lemme turn down the flame knob on the hopper on my 30th pass as i walk right by it.  this part is built and functions great, i dont want to fiddle with what is working well.  if it gets too hot inside that is a blessing.  open window, vent all the moisture and get some fresh air in. be a good thing. 

its easier for me to fiddle with finding adding storage to dump the hot water if overtemp is an issue.  which i wont really know for a few days of test and tune as i get this v2.0 online. v1.0-1.5 did learn me a lot but im still learning the sizing on of v2.

frost line here is 6 inches on a severe year.. most times a frozen pipe is a one afternoon wait for thaw and those problem spots all have icemelt cord and insulation so no there is no real frozen risk.  yes i have had a frozen pipes but thats mostly under a cabin crawlspace that i chopped all the plumbing out of because it was all wrong. everything about the entire place is wrong but weve outgrown a camper, kids are toddling anymore, theyre texting.  cabin will have internal plumbing, i refuse to be heating a crawlspace just for pipes and mice, or crawling under it all the time for frozen pipe repair, or having the puppy shred foam insulation to be scattered across the entire property every week.  i dont wanna have to shoot the puppy. interior piping suits me fine, its a shack anyway. i will never miss a leak or have to tear out drywall or rugs etc like normal people with that superior hideaway shoddy plumbing job behind a $1200 rug.  thats the reality ive seen any time i tore out drywall to fix plumbing or wiring issue.  pretty veneer.

a secondary tank is in the works to be modulate load and match it to the flame and changing daytime temps.  this stove im building now is to heat a camper and hot water for this winter.  then i will do a big OWB for 4ft green limbs (firebox is done, just not water jacket or controls) to heat every space i ever build on the front acre.. shop, cabin, camper, sheds, kiln who knows..  the little thing im doing now will become my summertime hot water heater.  so it is being done with a lot of expandability and relocation in mind.  its turning out very compact so far.  the other one was getting pretty close but i kept having an irregular stainless steel to copper braze joint fail and got tired of complete drain and dismantle to fix it.  delete boiler loop and redesign firebox to work by heating the reservoir direct.


will keep yall posted.

[DWyatt]

Here was a picture of the back of my OWB, it's bone simple. The white box is a thermostat that you set high and low set points. The grey wire is a probe that goes into the water jacket port above the two pumps. When the water temp drops, the thermostat closes the contacts and sends power to the solenoid connected to the blower fan that actuates to flop open a little door about an inch and turns the fan on at the same time. Go from a dead fire to a rager in 10 seconds. When the water temp hits the high set point, the loop is opened, closing the door and shutting off the fan. 

I had 1 thermostat and 1 solenoid go bad in 8 years. I'm convinced the fan was bulletproof. If I forgot to shut off the fill water, water would overflow out of the top of the stove and waterfall over the fan while it was running and I never had any issues. The fan blew into the ash pan and up through grates to the fire, sending air to the core of the fire.




 

[mike_belben]

Thank you for that.  Ive built v4.0 and this is the first night im going to bed with it running.  Ive gained a lot of insight on what does and doesnt work.  

[mike_belben]

Well in the heat of the moment.. Or lack of much heat for 2 cold weeks.. I guess 51 inside was the lowest i woke up to... We are livin in luxury. Radiant heated floors, no shirt on and i finally have a window cracked to let the swampy condensate out.  

For any reader just tuning in to my ridiculous lifestyle- I live in a camper for a while longer, why build my forever house just yet for my kids to destroy? We can wring the last drops out of the camper while they get a little more mature.  Campers are 3 season, have no dehumidification capacity, and drip condensate everywhere unless you open a window.  But they absolutely cannot supply enough heat to do that.  Used up my 4th blower motor in 5 years..  said enough is enough.  

I tried about 5 different versions of making junk into an outdoor flame appliance that heats water pumped into a radiator in the underbody crawl space to keep the pipes and our feet warm. Finally warm.

My deepest gratitude to BeenThere who PMd me a sketch of a small tank boiler he had which in my frusteration at all the fails that shoulda worked.. I threw in the towel and cloned aspects of his commercially made unit.  Ironically this is the only picture i took while fabbing away in mostly dark and sideways snow several days. but with a smile like that i knew it was gonna work. if you flip that smile 180 youll see the stoves water jacket orientation.






I cut up a free compressor tank and a gas grill propane tank welded one inside the other for a thin crescent water jacket.  One 4" flame tube and a 4" exhaust tube so the fire goes into the interior of the propane bottle. Pressure tested to 60 psi and submerged for pinhole repair.  One drain hole so that when it rusts out and leaks water it doesnt flood the flame, just dribbles onto the dirt to tell me i have to build another soon.

Right now am firing it with a manual propane gun. It was some 1940s oxy acetylene heat-treat wand that i picked up free along the way, put a cap on the acetylene port and a hose barb on the oxygen side.. Connected it to a fixed propane regulator.  Open a brass ball valve, strike the weedburner, stick it in the 4" flame pipe and walk away faster than i typed that sentence.

My exhaust tube is lower than my flame tube so most heat goes in the water.  The stack is running under 100F and you can grab it any time. So far it seems fairly efficient

Controls are zero. Full manual. No stats or safeties at all.  Its a small btu unit that really isnt capable of overproducing, and in fact will eventually become just my summertime water heater. It makes less flame than a turkey fryer. But for now its my boiler.   If the sun comes up strong throttle the gas valve back. At night open it up.  2 changes a day at most with slow response times.  

The pump never turns off and it draws .4amps this way.  My KWHs has already dropped from the electric space heater that couldnt keep up, finally shutting off.  

A box fan down below runs all the time to push the heat out of the radiator and heat the under compartments and black/gray tanks.  No more dumping hot water down the toilet to prevent it from freezing.

I cut some registers in the floor and tore out some furnace ducting i will never use again.   It took 2 days for the mass of the floor and walls and pipes to come up to temp but now it stays there, storing the heat.  The "basement" is warmer than the living space so the floors feel warm. That is a wonderful, luxurious feeling.  

I dont care how hot you made the living air, the floors were stone cold and you got a few minutes of ice water every time the faucet came on. You always felt cold here. Now i step out of a hot shower and stand right over the hot hallway vent and its just magic.  With forced air it would be 74 and cold. With hydronic radiant floors 67 is warm.

The original forced air furnace cycled on and off continually. It was loud, and would race up too hot then shut off and leave a continual breeze flowing from center to corners. Especially at startup and cooldown when it blew cold air.  The walls were slick with dampness that could actually ice up on a really deep cold snap as heat just blasts right out through the walls next to you.  The cold draft and hot/cold cycling kept me up.  

Now everything is so consistent and slow to change temp.  The sound never changes and has become white noise.  I can glance out the window and see a flame flicker any time its dark if i need to know the tank hasnt run out.  I know why the rich have variable speed drives on their hvac systems now, while the rest of us have on/off bimetal snap switch controls.  Nope, never again. No more start stop for me.  It just makes uncomfortable temp swings and expensive start loads.


Interesting discovery.. Black 3/4 plastic water pipe has handled boiling hot water unexpectedly.  I have pex sitting here waiting to go in but didnt havethe money when i started and needed to get some warmth in there before everything froze solid.  At the time none of my inventions were getting hot enough but it was an emergency.  Do what ya gotta do michael. If it melts it melts.

The lines are just laying on the ground uninsulated until i can get everything right and trench + insulate the pex then just switch over, flush, test, and refill with antifreeze.  Yes the heatloss is temporarily massive but so what i have the miracle of heat.  I throttled the pump flow down too slow one night and steamed off all the water.  The black water pipe was al dente but it didnt pop open. If it does i will mention it.  My mental rating committee approves black water pipe for 150F at 3psi or so no question.


 Right now its straight water in there for test and tune.. My whole system is under 15 gallons.  one 18 degree night with no fire lit i just left the pump running to circulate icewater so i wouldnt have to dump it and rebleed next day.  It never froze up. One more reason not to start/stop the pump is it struggles with a bit of air each time. I should build an air trap in the loop.

Now ive just gotta fabricate a crankshaft agitator into my sawdust and waste veggie oil feedhopper, which is the original fuel i have built all this stuff around.  It holds incredible free BTU but (unlike dry woodpellets that always fall into the auger) it is a clumpy tacky fuel that is hard to meter.  It burns best when loose and fluffy but is easily compacted into clumps by augers, and it forms a bridge over the auger so that a full feed hopper will run out of fuel and let the flame out.  


Once i get it feeding consistent i will have to get btulloh or ian to help me figure out an adjustable start/stop timer.  My auger is infinitely variable but as a fuel it burns better with intermittent feedings like a pellet stove.  Continual slow feed not so good.


Thanks for the help guys. God bless

[mike_belben]

 what do you guys recommend for the most economical way to combat rust in the boilers water jacket?  

also, are commercially water jackets typically vented or are they capped and running a few PSI?  

i am running open top with an expansion pipe and am losing a lot to evaporation.  straight water while i get things sorted and then i figured anti freeze for permanent but i dont wanna be losing tons of it. 

[beenthere]

To avoid rust cheaply, you have to de-gas the straight water and drive the O2 out of it. Cheapest way is to heat that water to drive off the O2.  
Add cold water and be sure to heat that water right away. 
Worked in my closed-system boiler for 40 years. No rusted steel water jacket. 

I understand there are products to add to the boiler water, but do not know what they are.

[mike_belben]

Mine is not always gonna be hot so i cant count on that. Its puking tremendous foamy rust blobs. 

[mike_belben]

Boilers dont typically have filters do they?

[Southside]

Couple of thoughts - what about some of the conditioners used in diesel cooling systems?  If not that - would some of your filtered veggie oil work in place of the water?  

[mike_belben]

No im using a copper radiator, itd catalyze into poly super fast.  

[PoginyHill]

Water contains the least amount of dissolved oxygen around 200F. Pressuring it would ensure oxygen wouldn't be re-absorbed after it's cooled. A pressurized system would need a vent to allow gases to escape once they've been driven from the water. An expansion tank is best as it separates the air from the boiler water. Or you can add something to raise pH to 9.0 or so.

[Hilltop366]

Once i get it feeding consistent i will have to get btulloh or ian to help me figure out an adjustable start/stop timer.  My auger is infinitely variable but as a fuel it burns better with intermittent feedings like a pellet stove.  Continual slow feed not so good.

That is kind of how the Harman pellet boiler I have in a apartment building works, it has a high temp, low temp, and feed control I plumbed it to pre heat the return water before the oil boiler, I can do this because it is a continuous circulation system I don't get a cold shock on the return. If the circulators did not run continuously I would have put a separate loop from one boiler to the other.

The feed system has a small door in the bottom of the hopper that opens then the auger runs, the door is a safety to prevent fire backup in the hopper as well as the lid on the hopper is quite tight and latched down. the higher the feed is set the longer the auger runs each cycle and as the maximum boiler temp is reached the less pellets are fed into the burn pot. There is a safety over heat protection and restart as well. The blowers (burner pot and exhaust) run all the time, heat output is controlled by fire size.

If you could control the feed auger speed and the auger run time you should be able to control the output quite well, staying above 140f well keep the fire box dry.

Pressurized systems run at around 12 psi, typically have a pressure regulator and a back flow preventer in the feed line. Pressure relief valve is factory set at 30 psi and should be vented to within a few inches of the ground. And as mentioned a expansion tank is needed. A way to bleed off air at the highest point is really handy too.

Another idea would be a semi pressurized system, leave a raised opening on the top of the boiler with a weighted lid the boiler would be full but there would be a air space for expansion in the raised opening. I would still add the pressure relief valve incase the lid sticks. Some experimenting would be required, I'm thinking a 12psi fill with a 30psi relief valve then weight the lid to let off pressure at around 25 psi.  

[mike_belben]

2 great posts in a row, very insightful.  thanks gents. 

i have moved on to several more revisions in sort of a trial/knowledge frenzy, and sort of a seeking the best system for my life.  i havent taken pictures or documented any of it and have covered a lot of ground.  

for now due to lack of time and money the sawdust/veggie feed hopper has been shelved, every fix created new issues and i know when im getting frusterated i need to do something else for a while. i need to solve the issue of bridging and compaction in the feed hopper and just dont have the stuff on hand to do it right.  the gear box and resistance from the fuel is enough to break a lovejoy, to give some perspective on what im dealing with. 

this has all been an unexpected benefit because it shaking out 15 not great ways, i mentally wandered over to what i hope to get working on today, which will be so much better than what i was working on if it goes right.  sometimes its better to drift onto a better island than cling to the crummy one youre on. we shall see. 

[Hilltop366]

Almost like you would need some sort of scraper/packer that then covers the feed area while a plunger pushes the fuel into the fire chamber. Could be run off of one rotating mechanism where the leading edge would scrape the bin and have a snowplow shaped leading edge to roll the fuel in a tube shaped troth with a open top as the scraper goes passed it then covers the troth and a sprocket on the outside of the bin has a ramp that actuates a rocker arm to push the plunger in and out to push the fuel mixture in.

Probably easier to burn firewood and shovel in some of your sawdust and oil once in a while.  

[mike_belben]

theres a million ways to do it, but you need to know how not to fabricate the feed mechanism first, in order to fab it right the 5th time.  i have crossed that first bridge.  

i heated entire house for 2 years on a baffled wood stove by shovelling in sawdust and oil in batches.  it requires massive turbulence to burn in piles.  youve gotta blow off the charred layer and reveal the next or itll smolder out. a blower will make it run away or blow the fuel up the chimney so theres a balance. 

i had to do this as a disposal for the sloppy watery settlings from processing road fuel. i had a contract with a sheraton hotel for grease removal and couldnt keep up, it was overwhelming.  hundreds of gallons a month.  when the entire shop i rented was full of barrels i had to buy totes to consolidate drums into just to get in the door. woulda stacked them if i could have but low ceiling prevented it. 

[mike_belben]

now lets say you had a feed mill and had ground, dried proteins and carbs you wanted to pelletize for dogfood.  waste vegetable oil is your fat and your binder. cant keep a dog off the stuff.  it taste like a hodgepodge of every fast food there is.  canine crack.