boiler questions

[torence 20]

ok guys i have read posts for days hours on end about boiler set ups but i cant seem to find an anser to my question, so i have an old energy mate indoor wood boiler that im going to build a shed and insualte it and make it an outdoor unit my question is this unit is a sealed unit with no draft control on it only a forced draft blower so i understand that i use and aquastat to tell the draft blower when to turn on 170 degress or wht ever you set it at and shut off at 180 my question is if the fire burns out and the water drops below temp how do i keep the draft blower from turning on and running non stop until i manually shut it off and build another fire?

 

[fixit1960]

ok guys i have read posts for days hours on end about boiler set ups but i cant seem to find an anser to my question, so i have an old energy mate indoor wood boiler that im going to build a shed and insualte it and make it an outdoor unit my question is this unit is a sealed unit with no draft control on it only a forced draft blower so i understand that i use and aquastat to tell the draft blower when to turn on 170 degress or wht ever you set it at and shut off at 180 my question is if the fire burns out and the water drops below temp how do i keep the draft blower from turning on and running non stop until i manually shut it off and build another fire?

You don't ....

 

[fixit1960]

Well, I take that back, you could. You would have to wire in an opacity sensor into the fire box and wire it into a timer. When the forced draft fan turned on it could start the timer, which you could set for however long you wanted it to time. If after that set time you did not have a fire in the box (provided the lens was not carboned over) it would kill the power to the fans. That's a lot of work and to much electronic gimmickry. Better to just plan on being there at the end of the cycle to stoke it. That's the downside to heating with wood.. .

 

[Henry Fuller]

You can installed a inline low temperature cutout 140 F (snap disk or adjustable stat control) with an manual bypass toggle switch connect parallel with the cutout switch/control circuit, when the water temperature reach 150 F and above (depend on differential setting) just turn the bypass switch off as your wood fire build back up and going again.

Henry

 

[Joesell]

Do people let owb go out? How do you keep it, and the lines from freezing?

I'd say the best bet is to keep it full of wood!

 

[Rockarosa]

I light up my Cozeburn in late October and keep it fired up until late March. It's a lot of work and it's easy to get hurt or killed down in the woods cutting trees down. But my house is warm and it helps keep this old man in decent shape.

 

[Paragon Builder]

You can installed a inline low temperature cutout 140 F (snap disk or adjustable stat control) with an manual bypass toggle switch connect parallel with the cutout switch/control circuit, when the water temperature reach 150 F and above (depend on differential setting) just turn the bypass switch off as your wood fire build back up and going again.

Henry

This is exactly how I would do it too. But you can add a simple twist timer in place of the bypass switch. Simply crank the timer on every time you load the stove to give it time to get up to Temp. And when the stove runs out of wood the low cut off will kill the fan for you.

 

[fixit1960]

You can installed a inline low temperature cutout 140 F (snap disk or adjustable stat control) with an manual bypass toggle switch connect parallel with the cutout switch/control circuit, when the water temperature reach 150 F and above (depend on differential setting) just turn the bypass switch off as your wood fire build back up and going again.

Henry

I like that idea Henry Fuller. Cleaner and simpler than my suggestion. Do you use this method or have you seen it installed?

 

[fixit1960]

Do people let owb go out? How do you keep it, and the lines from freezing?

I'd say the best bet is to keep it full of wood!

To answer your 1st question, NO, I light mine once a year in the fall and it has a fire in it until I give up in the spring.
2nd question; My system holds about 180 gallons of water so when I installed it way back when I added 50% antifreeze, In the event something happen and it went cold it would not freeze and destroy my system.

 

[hanniedog]

Should be able to do it with an aqua stat and a relay. Stat gets to 150 trips and drops power to fan. My boilier system uses a stat to keep the propane unit from running until the water gets to 140-150.

 

[NSMaple1]

A second simple make-on-rise aquastat, wired in series with the first one, or between the first one & the fan. Set it for 140 or 150. When the boiler is that hot it closes that part of the circuit and all fan control rests with the first one. If the temp drops below 140 or 150, it will open & interrupt control to the first & the fan will not run.

Easier to do if you get an aquastat with a strap on sensor - then it doesn't need a well. Or use a Johnson A419, it has a surface mount sensor - plus a handy digital temp display.

 

[06switchback]

I would do just as NSMaple said but put a bypass around the low temp Stat so when the temp is low you can switch the blower on to bring the temp back up

 

[torence 20]

i like the idea of the low temp stat with the bypass thanks alot for the info guys, i dont plan on letting the fire go out but ive also read that these older burners only get 4 to sometimes 6 hrs of burn time so working at 8 hr day obv i wont be around to fill it up. ive got an indoor unit in my basement now thats forced hot air but im tired of the mess in my house and i think that using the indoor air for the combustion process it makes my home more drafty as its over 100 yrs old. either way its going to keep the mess out of my house and cut how many times i have to handle the wood in half so i am looking forward to that

 

[Henry Fuller]

I like that idea Henry Fuller. Cleaner and simpler than my suggestion. Do you use this method or have you seen it installed?

fixit1960,
I been doing HVAC (self employed) for a living, I have customers that I set up multi-controls tied together with indoor boiler and outdoor wood boiler combo, ect.... You'll be surprise how long before outdoor pipes will freeze up when wood are gone (like half a day or longer if insulated right and protected from the wind). I had one customer boiler went down over 18 hours (cir. pump quit working) in 0 F degree in the night and lucky nothing frozen up and no fire when I first got there. I just remember, when you have time (a day or 2 reading this) look up on this AS and search for shaver boiler, somewhere had wirings and controls information.

Henry

 

[torence 20]

thanks henry, i plan on burying the insulated pex below the frost line at 5 foot and the boiler will have a well insulated shed built around it and my circ pump will be on 24/7 with a second on standby if a problem were to arise so im not going to run antifreeze im doing infloor heat in the garage so that will be where i have to worry if something does happen to my circ pump but still with that concrete slab warmed up to temp it should maintain for a decent amount of time

 

[fixit1960]

thanks henry, i plan on burying the insulated pex below the frost line at 5 foot and the boiler will have a well insulated shed built around it and my circ pump will be on 24/7 with a second on standby if a problem were to arise so im not going to run antifreeze im doing infloor heat in the garage so that will be where i have to worry if something does happen to my circ pump but still with that concrete slab warmed up to temp it should maintain for a decent amount of time

I agree with your train of thought, but my piece of mind dictated to me back in 1997 when I installed mine to just go ahead and install the antifreeze and not worry about it. My kitec tubing is also 4 ft below ground and in insulseal. It is exposed in the back of the stove and it's the only heat source for my garage so if I have a flame out and am not there for a day or 2 I don't have to worry about my plumbing above ground and the heat exchanger in the garage. Back then a drum of antifreeze was about 170.00. I check it yearly for PH level and add corrosion inhibitor. No worries if something goes wrong or I can't fire it (which has never happen). I think I've got my investment back as far as adding antifreeze.....

 

[Henry Fuller]

torence 20,

When you get ready to do your garage floor pouring, prepare elevateded surround above ground level for drainage, use crush stone (well tamp down), vapor barrier , insulation boards also around the outer edge , rebar/wire mest and add expansion joint when you are pouring your floor. I have seen too many cutting corner on this type of job. I have seen one place had a foot of clearing of snow melting around the outside of building (big heat loss), slab buckle, another where no insulation under slab (big heat sink), ect... You will enjoy your heated garage floor when done.

Henry,

 

[torence 20]

fixit when you put it into perspective like that 200 bucks will be alot cheapter then jack hammering a floor out , and henry thank you for the advice i was planning on doing almost everything you mentioned im not sure what you mean by elevated suround above ground level you mean i should core out the sod and put my rock down above grade and then pour on top of that?

 

[torence 20]

fix it what kind of system do you run, how many gallons? did you have to buy a certain kind of circ pump to run the antifreeze? are you heating your house also with it? did you do a heat exchanger in the plenum? sorry i have so many questions for you. where in iowa are you lol ill come look for myself jk lol

 

[taskswap]

I wonder what Energy-Mate you have - I haven't heard them mentioned in a while. I have one myself. I wanted an indoor setup, but couldn't afford a brand-new boiler AND the plumbing and controls etc. to install it, at the time, so I compromised and bought an Energy-Mate from a guy on eBay who takes them out of basements where people want to get rid of them, and fixes them up - new paint, fully relined, pressure-tested, cleaned, etc. I figured I'd use it either for several years or until it gave out, then get something better and more efficient.

I don't know what unit you've got there but mine definitely gets only 4-6h. It's a pretty large firebox, but it's super inefficient compared to what a modern boiler will do and I'd be shocked if it was more than 30% efficient. The forced draft is nice in terms of never having to worry about your chimney drafting well, but I've had plenty of second thoughts - it's not a HUGE amount of power, but it needs it the entire burn cycle. A natural-draft damper setup can be adjusted. This thing is basically on or off. IMO you hae to watch your loads more. On warm days, too big of a fire runs the risk of overheating even if the draft fan is off and sealed tight. I rigged mine to force zones in the house open if this happens so at least the heat gets dumped where it's useful, but still... It's a waste.

I went with a slightly more sophisticated system than people are suggesting above (I'm an amateur electronics hobbyist so I built a Raspberry-Pi controlled unit that I had all kinds of plans for, then had another baby and kinda stopped as soon as it was barely "good enough"...). You CAN just leave the ash door open while you're lighting it, and stand there until it's up to temp and the low-limit kicks on the draft fan. But that's annoying and not safe if you're going to walk away, so a snap-disc set at 140 to turn it off, and a simple light-switch timer in parallel to it that you set at like 20 minutes is a good way to address turning the draft on and off at the start/end of a burn.

You want a bigger swing on your high/low limit though. You don't want to set it close to 165 or the system will "hunt" a lot and produce a really inefficient burn. It's much better to let it swing to like 185 or higher - whatever you feel safe at (and your plumbing can handle), and then down to like 165 or so on the low side. Nothing is going to make this unit amazingly efficient, but it's definitely MORE efficient when it's running hotter - and more efficient at heating your house, too. Usually you also set the aquastat up so that any demand forces the draft fan on even if the boiler temp doesn't require it. Most of these don't have those 100-gallon reserve that those "I don't even split my wood - just dump it in with the Bobcat" folks have on the shed-sized beasts they have. What happens is, if it's been a bit since the last call for heat in the house, there's loss in the lines that the boiler needs to replace. But the aquastat well is almost always on top of the boiler - where you draw the heat off from. So the first few gallons you draw off to heat the place don't register as a dropping temp to the aquastat, and it's not running the fan. Then, bam, the cold water coming into the boiler reaches the top and bam! suddenly it's 145F or whatever you set your mixing valve to. Now the system panics, shuts off the circulator and stops heating your house, and fires the boiler - several minutes later than it should have.

It's also good, if you have digital thermostats, to set them up for a bigger "swing" too. Wood is just not like oil - it's not an on/off system. It has an efficiency curve in its burn cycle, and damping it down doesn't put it out - it's still producing 10% output in most cases, and if you aren't putting that in your house, it's going up the chimney. It's better to have something more like 66-74 than 69-71. Just like a wood stove, in a way.

A digital aquastat is really nice here. Until I built my HotPi unit I was using an L7224U and pretty happy with it - they're cheap on eBay FWIW. I didn't bother with something to disable the draft fan, so it would keep running after the burn was done - but that didn't happen much because I had to run the thing flat-out just to keep up with that "Polar Vortex" we had. Anyway, I wired my zones into the "demand" input, set my low-limit to 165F and my high-limit to 190F and had pretty good success with that for a long time.

Love a pic or two - I'm curious about what unit you have.