flue temp

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KarlK

Member
Hearth Supporter
Nov 28, 2007
82
Pa
Can anyone tell me how to get my flu temp up on eko 60 at best Im at 200 at the collar on the boiler. I seem to be getting condensation out of my masonry chimney and its dripping water at the base of the chimney. My primary air is open 1" my fan sliders are 1/2" open and my secondary air is 6 turns out.
 
I am assuming you are burning dry seasoned wood? If you are, try opening the primary air fully and then open the fan sliders a little more maybe up to 3/4." Also when this is happening, is your water temp in the boiler above 70 degrees celcius?
 
Does that model have a click temperature switch on top to limit the pump running until it hits the proper temperature? My EKO 40 came shipped with that switch.

It sure sounds like a problem the could be caused by extended periods of cool return water temperatures.

Look to see 130F or more at the return pipe at the boiler within 15 minutes. Get a strap on thermometer or a point and shoot temperature gun. That is critical or you will end up the the pictures in the post above ;)

Also a tall masonary flue will take some time to warm. Is it inside or outside the home? Is the chimney sized properly? To much flue dimension or to much draft will cool down the flue gasses and encourage condensing in there. A draft gauge would be handy to test draft accurately. Excessive draft may call for a barometric damper.

hr
 
I have a eko 60 with no storage right now its warm outside so I idle alot I have primary air open 1-1/4" fan sliders open 1" and secondary 6 turns . Im trying to adjust the fan pulse time from the factory setting of on every 6 minutes for 5 seconds to 4 minutes 5 seconds in order to raise flu temp . right now at idle my flue temp is about 160 . It seems ok during the day but at night when I load for all night burn I wake up to condensation at the base of my chimney. Am I on the right track?
 
You are correct. You have way too much horsepower and little, to no load. That boiler really prefers to run hot and long, and that is the only way things will warm and dry out. Pulsing may not offer much relief.

In all honesty this time of year when it warms into the 60's during the day, I shut 'er down and go back to lp fired heat. The cost of keeping a building at 70 when it is in the 60's is so low. Passive solar may even do the job :)

It's not a fun job cleaning out a creosoted boiler and or chimney. Efficiency goes way, way down when the boilers get a layer of creosote on the HX walls. It insulates the fire from the heat transfer surface, if it gets bad enough you'll be breaking out the hammer and chisel. Flue draft gets impaired also as the creosote layer builds. It's just not worth the risks. A boiler that size may not be a 4 season appliance. Storing or dumping heat gets a little silly when you have too much firepower.

I know Taylor owners that have had to use roto-hammers to clean out their fire tubes after idling them excessively.

hr
 
Thanks for the imfo I just got the boiler and wanted to run it a few days so I know what to expect next heating season I was hoping to resolve this so I know it isnt some other problem. It runs good all day if Im around to keep small fires in it . It only seems to happen at night when I load for 8 hr burn.
 
Yeah, heating with wood is a pretty interactive sport. It takes some hands on to get everything burning smoothly. With practice it gets easier, but they really have a one track mind. With a firebox full of fuel and a low or non existent load they become a bit "high maintenance" Like a race horse they prefer to go full speed ahead :)

hr
 
He's got one of the newer models like mine, hr. They have turbulators that move up and down when you yank on the handle. This keeps the creosote from building up too much in the tubes, as long as you shake the handle when you load the stove.

But you're right about warm temps and excessive idling. Ironically, I thought that dirty hx tubes caused higher stack temps because there's less heat transfer into the pressure vessel.

I run my 60 in this weather with no storage, but I do it by burning a small, hot fire in the morning, then another small, hot fire before bedtime. It's probably not the most efficient way to fly, but it allows the boiler to run hard for a shorter period and avoid a lot of idling. I've noticed that dry pinecones are a very good fire starter, since they seem to get gasification going a lot faster than plain firewood or hardwood kindling.

Anyway, I never see stack temps that low. Mine tend to hang in the 350-400 range during normal operation, with occasional spikes as high as 600 or 700. And I never have any condensation or creosote formation at the exhaust, for that matter. Just a little bit of gray ash in the cleanout.

Nofossil has some data pertaining to stack temps on the EKO, I believe. I'm hoping he can shed some light on your problem. I think leaddog also has some empirical observations on his 80. The masonry chimney may be a contributing factor. I'm thinking it's more likely something you can manipulate with the air control settings. I think it's generally accepted that anything below 250 puts you at risk of condensation.
 
I think it's excessive idling, plain and simple, though I'd check the controller wiring and setpoint as well. If the controller is maintaining a water jacket temp of 180 degrees or so while idling most of the time, that could cause what you're seeing. My analogy is a race car engine - it's designed to run hard and fast, and it doesn't like to idle.
 
My boiler water temp is set at 180 it has a 10 degree drop point so it comes back on at 170. The highest flu temp I seem to get at gasification is about 250 . I only have a cheeper magnetic thermometer it showes in 25 degree increments but I dont think its off that much . Today I installed a dampener on smoke pipe ,its a new chimney maby to much draft ?
 
KarlK said:
My boiler water temp is set at 180 it has a 10 degree drop point so it comes back on at 170. The highest flu temp I seem to get at gasification is about 250 . I only have a cheeper magnetic thermometer it showes in 25 degree increments but I dont think its off that much . Today I installed a dampener on smoke pipe ,its a new chimney maby to much draft ?

If you're measuring flue temp with a magnetic thermometer, then you should likely see around 250 at full tilt. That's what I see on mine. The actual flue temp is quite a bit higher on mine - around 500-550 as measured with a thermocouple.
 
Thanks nofossil that makes me feel better. I just started a small fire with one nozzle, got up to temp but it takes a while with 1 nozzle now Im going to let it go out like Eric does it just seems to me that I will get condensation when it cools off I hope Im wrong.
 
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