CB-2400 temp patterns

[Bob Lentz]

So this winter i noticed that we were burning 30% more wood than previous winters. This winter was much warmer too!  So i started tracking down what was causing the demand and realized out domestic hot water re-circulation pump was running 24/7.  So i re-set the timer on the pump and things got back to normal.

One of the other things i have noticed while i have been monitoring the boiler closely is that under demand, the temps will dip down to the 165 degree area before being brought back up to 185.  I run a 175-185 diff with pulse every 15 minutes for 40 secs.

This just tells me that under demand, the boiler struggles to be brought back up.  i am thinking of changing pulse to every 12 minutes for 40 seconds to help keep the coals a bit hotter.  Also thinking of upping my range to 180-190. Sometimes it takes the boiler an hour of burn time under demand to bring the temp up from 165 to 185.

Thoughts?

[beenthere]

Bob
Where do you think the extra heat was going?
30% must have been going somewhere when the re-circ pump was running 24/7.

[doctorb]

Bob-

Have you checked the solenoid elbows for creosote.  It sounds like the entire operation has lost some efficiency.

Doctorb

[doctorb]

Bob-

Just read the other thread where you said you pull and clean your elbows three times a year.  So it's definitely not that!

[garret]

I observed (and attempted to quantify) that even light accumulations of fly ash and other combustion products coating the two rectangular heat exchanger (HEX) passages in the EC2400 noticeably reduces efficiency.  I now brush these passages about once every month and vacuum the area between the HEX access and the flue, as well as the area behind the by-pass door from inside the stack clean-out tee.

I designed a simple-minded experiment where I would monitor the Firestar II temperature display, stopwatch in hand, on the same day, before and after cleaning the HEX in an attempt to quantify any improvements in performance.  I realize this is something difficult to quantify due to so many different variables.  I was surprised to measure a nearly 50% reduction in the time required to raise the water temperature from 188-195 F (water temperature recovery after cleaning, 10:15 min:sec vs ~14:40 min:sec, before cleaning).  The clock was started when the furnace entered high burn during each measured cycle.  The RC temperature high reading was 1410 F on the first determination and 1290 F on the second (after cleaning the HEXs).  The measurements were made less that 6 hours apart, so the heat loads were assumed to be approximately the same.  I allowed one cycle to occur after the cleaning and before the second measurement, in an attempt to allow the furnace to equilibrate, as the furnace power was also disconnected during the cleaning and significant cooling had occurred.  Even though this experimental procedure is admittedly a little sloppy, IMO the observed changes were significant and surprising, especially because the high RC temperature was lower after the cleaning (has nothing to do with the cleaning, because airflow was not obstructed). I may even consider more frequent cleaning on the basis of this experiment.

I pondered whether I should share this kind of information because it will undoubtedly invoke many criticisms of my methods and conclusions.  Here goes.

[Bob Lentz]

Garret, don't sweat it - i believe there is a vast amount of information that is not shared when it comes to making these things run well.  I clean my HEX every 3 months along w/ the elbows.  Please share what kind of tool you use to clean the HEX.  My dealer recommended a spacial garden tool that is modified to fit down between to scrape the HEXs. I have never brushed them though. I kind of remember that when the unit was new, it really heated the water faster!

[Bob Lentz]

BeenThere, you asked where the heat was going. It was being lost in the house crawl spaces and in the walls.  I have two side arm water heaters. They are on opposite ends of the house.  The pex that runs between them is about 85ft. So pumping water from one tank into the other tank, then around the house causes the loss.  It only dropped the DHW temp about 1 degree an hour, but that degree was causing the side arm to call for heat to make up the 1 degree all the time.  so, the boiler was just working to make up that 1 degree. 

[boilerman101]

Bob, how long has your wood been seasoned and how high reaction chamber temps do you get each burn cycle?

[Bob Lentz]

I purchase my pinion from a firewood distributor here in CO so i don't really know how seasoned it is.  it seems to be pretty dry. Burns very, very hot.  My RC temps get up into the 1400's.

[Bob Lentz]

I purchase my pinion from a firewood distributor here in CO so i don't really know how seasoned it is.  it seems to be pretty dry. Burns very, very hot.  My RC temps get up into the 1400's.

[garret]

Bob,
I have an EC2400 manufactured early 2014 with the 2 rectangular and downward-curving slot-type heat exchanger passages that CB refers to as "heat x-tract system" or some such thing.  They provided me with a simple twisted wire-handled, wire brush having a bow tie-shaped cross section.  It fits snugly in the slot and is easily bent downward while brushing.  Cleaning doesn't offer much resistance and the adhering deposit is a dark brown powdery fly ash.  There is also a very light and fluidy powder fly ash that accumulates in the area above the passages probably due to simple gravimetric particle segregation.  The dark brown stuff appear to reduce the HEX efficiency mainly due to its acting as an insulator.  It offers little resistance and is easily removed and piles up in the RC.  I used to shovel this brown deposit out, but now just leave it in the RC because it still has heating value.  It appears to contain a fair amount of high temperature pyrolysis products entrained in ash that upon incineration converts into just plain ash.  I have to compliment CB that the draft from the stack prevents this stuff from blowing in your face while brushing and stirring up the dust.  Probably not by design-CB lucked out on this one.

[Bob Lentz]

Well, i just did a spring cleaning of the 2400.  This time, i scooped all the ash out from behind firebox and under the stack.  Never had done that before.  This was 4 years worth of ash! So, now the hex, stack shelf etc is clean along with the reaction chamber.  Will watch it now to see if it does better.

[boilerman101]

Wow, I have to believe that was a lot of ash if it had not been cleaned for 4 years! Wasn't it built up pretty full in the chimney tee cleanout as well restricting air flow?

[Bob Lentz]

I had cleaned the stack before, and did my best to remove ash from just to the right of opening for the HEX. However, i had never reached around and back under the T. So yes, there was quite a bit of ash in that area. I just put on an hold sweat shirt and a good pair of leather gloves and reached around and pulled the ash into the opening for the HEX.   I also used the wonder bar allow me to reach further over. Never thought to reach over there.  Glad i found a mention of this in another post otherwise, i never would have known to do that.

[boilerman101]

I use a shopvac  nozzle to reach the ash all the way across that shelf area on my final shutdown cleaning for the season. It works well. Otherwise I reach across with a hand trowel to pull it back to the cleanout opening once or twice during the heating season.

[Bob Lentz]

i can't believe nobody, not even CB has put together a guide to maintenance for these things.  Maybe we should put one together and make it a sticky?  If i had not come across a post that had mentioned cleaning that area, i never would have done it. What else am i missing? At this point, probably not much.

[JimBod.]

I have a E 2400.  This was the first one (?) My dealer sold.  I am still figuring the thing out.  The manual isn't very helpful on how to clean. I am thankful for this forum.  A guide to cleaning and maintenance would be great!

[boilerman101]

A couple of years ago I received a CDE with 3 videos on it mailed from CB. I believe this video comes with all Eclassics they sell now days. Videos were: Initial Start-up, Re-fueling Tips and Eclassic Maintenance. All are excellent and should help any newbe start off with all they need to know without having to learn it on their own. The maintenance video is excellent and shows everything for daily, weekly, monthly and end of season maintenance and cleaning procedures. Includes showing cleaning the primary elbow and cleaning the shelf area behind the chimney tee. Didn't you guys get one too?

[JimBod.]

Yes. Maybe I should watch the DVD.