John Goodbody

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since Feb 23, 2019
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Recent posts by John Goodbody

I'm very interested and shall try it this week. I have plenty of drums. Only problem: there won't be much room between them... they are 94cm tall, 59cm dia of open end and 52cm the other.
So what about the hole? Should I cut out whole bottom or just drill small holes? In previous post you mentioned fan too.
Can't wait to see the result

Thanks for the heads-up on stainless. Glad I shared this idea. Otherwise I would make another pricey mistake

The rattling airer (I figure that is what you refered to) was just the consequence of pulsing. These stone walls don't seem to be dumping vibrations. I have a diaphragm water pumped fixed to large boulder and it doesn't reduce the noise. When heater started panting, house started vibrating. Just now I had a thought which part of RMH would start these vibrations. Most likely it would be duct (which might have 'loosened' somewhat when I hammered cleanout caps in...), but could also be the floor... I really don't know what will be causing this. In 60 mins it appeared just like that for 60sec and just like that it disappeared... It was like... like something abruptly blocking strong draft. It certainly felt so around feed.
2 years ago
Time to report!

Although problems that are not logical in the yes/no sense are not my speciality (which is the case with my heater), I am inclined to say that this morning has brought me some joy.
To start with, following Julian's instructions, on Saturday I tested for leaks. Saying I was disappointed not to find any around the heater would probably be improper However, both cleanouts in the other room leaked.
Then, I swapped drum for another, unpainted and with no corrugations. It also turned out to be slightly wider towards the top (when upside down), which puzzled me because I thought I had used the widest one
This new bell is not yet embedded (last time I made a concrete ring around and spaced it with ceramic blanket, thought it would be much easier to reembed the barrel) and second leak test revealed some smoke there which I closed just for testing.
There was some panting. I was very surprised because seconds before it started, I'd assured myself about improvement in opperation.
System pulled nicely. Which, in absence of spinning cup and with some air movement outside, was a positive thing.
With correct draw, I could hold my palm over sticks and could easily tell good draft. Flames always pointed downwards (even from halfway up the tube) and top bricks remaind cool. One couldn't even tell much heat rising from embers.
Then the panting started and stayed there for about a minute. Airer hung 15' away was rattling. Even then no smoke escaped up and flames didn't seem to be changing direction. But obviously, with draw broken up, at least some heat started to climb up, warming upper feed tube. All in all, it was nothing to write home about, but worth pointing out.

To sum up, when fired every day, heater runs fine and I would like to attribute all symptoms described in this thread to cold firing and warm weather (actually, two days ago I was sunbathing for the first time this year - it's the climate here, two seasons: summer and winter). However, hints by other members have lead to improved opperation (sealing leaking heat exchanger and using unpainted barrel).
When this pulsing started, open front door didn't seem to make any difference. Neithere did partly closing feed or shuffling sticks. I forgot to spray drum with water, but, since ocstructions and restrictions have been pointed to cause this behaviour, I think it may have to do with my manifold. Closer look revealed it is slightly narrower than the bell. Perhaps I should have offset the last course of bricks I added two weeks ago. In any case, if I am to rebuild it, I will certainly try to use metal manifold. I now see why most people have them.

I think that I will now rest reassured until October or early November. Hope that cooler temps and different atmospheric pressure (as was also suggested here to be causing problems) will ensure correct opperation.

Twists and turns of my design don't help with cold firing. Nor does the distance between bell and chimney. Vertical piece that runs by the drum helps push gases, but then they have 3x 90deg elbows, 1x 180deg 'U' and final 90 deg albow to the chimney. Hence use of spinning cowl, but I think even more important is warm bench (and cool air sucked in through cleanouts didn't help much with that).

Any suggestions to wrap this up are very welcome!

I want to embed bell and I am tempted to lighly paint it... only outside but am afraid it could cause problems again... Maybe second drum, like Julian has suggested, is the way to go? Definitively cheaper than stainless bell
2 years ago
I will definitely remove the paint but I don't want to do it just now. Don't want to let the system cool down until I am sure it works as I want it with warm bench.

To be honest, I don't think this strong draft a problem. I don't see an issue with fuel consumption... There are 300 trees and there is just too much of twigs and small branches. And this is what I like about this heater, that it works better with small fuel rather than logs. I would not even say that the fuel races through... It is hard to tell how much firewood I have used this winter, but I'd say about >1m3 of larger pieces (2-6'') and 1-2m3 of kindling/twigs (weight-wise it was less than the former, but volume-wise it was way more, hence not easy to tell) - that kept the house between 21-25C (70-77F). Few people round here would insulate houses and many would use open fire. Compare with them, I was very impressed by my results.

As for the hot chimney:
I don't worry about heat loss too much (this morning I reached over 80F with open front door, after just over 60min burn, using mentioned sticks), and am concerned about proper draw.
Last year, before adding 3m to the bench and making it into 'L' (if you refer to my diagram, there was only 8' length along the stone wall), bench would be WAY too hot (melted my camping matt) and chimney way hotter than now. Hence the addition of quite a few more turns.
Having said that, I am very happy when it pulls strong and loud.

I understand it very well that RMH require some attention and understanding from operator. Problem is that throughout this winter it has worked so well (sometimes I didn't even bother lighting it properly and would shove sticks in, then place piece of cardboard on top and light that! No problems lighting it this way! Such was the draw. Perhaps too strong when windy, but I could live with that), that is spoiled me! Maybe this has cause problems I have been dealing with: because I was not carefull enough or too impatient...

As I said, I will keep firing, then will scrape paint off the bell, perhaps try another one on and test for leaks.
I will test, compare, compile and report.
But I can see a change already. So I hope it is only my 'right now' attitude that is to blame.
Fact is, I have never seen another rocket. I didn't know what to expect. But perhaps the way mine behaved was not very uncommon.... All I wanted was my old heater nothing more and nothing less!

Julian, I remember you asked what had been changed.
I did paint the drum and partly rebuilt feed tube.
Last year I wasn't happy about the operation. It behaved in a way like now (some smoke and swirling of flames at the back of feed). I completely rebuilt the engine and added insulation, then extended bench. I was very happy about improvement. Perhaps it was far from an avarage rocket, but I was glad. This is why I hinted a few times about rebuilding again, hoping to fix it again. Would be easy, but I don't want to rebuild every year. That's why I insist on finding answers.
2 years ago
A second drum? I see the concept. This way, the inside one doesn't have to be painted too. I have a few drums that I was going to take down to scrap yard. May experiment with them.
Anyway. First things first.

I had a really strong draw. It is still windy, which helped. Though I have to removed the spinner itself, I took its cap off so I don't know if rotating blades made any difference, because gases were free to go straight up (blades are on the outside; centre has only a cross that holds them in place). When came back in, I thought that this had improved draft, but it is normally loud and think I have this impression every time I enter the house.
Throughout the burn, I also kept cooling the bell, as advised. At first, I thought it improved draw but I'm so eager to solve this enigma that my hopes can deceive me. In any case, while cooling the drum, first with wet cloth and then spraying water, I realised that the bottom MIGHT (I do not have a digital thermometer and a fluid one that I am using will not give me realiable readings) have been warmer than the top... Should that be the case (and I figured it by the amount of steam and how fast it was produced), it may have something to do with the shape of this drum. Top of the inverted thing is corrugated (only gentle corrugations but still), while the bottom is plain. Since corrugation may decipate heat faster, the impression I had may be correct.

To keep this post as short as possible, at no time did heater show any signs of smoke trying to climb the wrong way out. Moreover, I did not see smoke (or steam) at the back of feed tube (flames there were sort of lazy, but pointed towards burn chamber and no smoke or steam were swirling there).
It pulled correct and strong even when only embers were left (at that point chimney's temp was as high as bell's, which is correct but would not be the case over previous firings).
Interesting and surprising was that the bell itself stayed quite 'cool'. I am sure it was due to strong draft. In turn, there was no need for cooling it, there were no indications of heat trapped in there and paint too did not give off almost any of the annoying smell (I actually forgot all about it, because it wasn't noticable).
Yesterday I sealed the thermal crack in manifold that I mentioned earlier. Because it only appeared during heating, I had to do it with hot manifold which dried mortar too fast and it is very brittle. The idea was to fill up the crack so it will not be closing and opening again. Not sure if my logic was correct. I read that epoxy resin should be used but one I have are for plastics and wood. Not sure it those could be used with concrete.
To test for leaks, I will have to remove spinner so didn't do it at the end. But just wondering if there would be need for that.

All in all, would the symptoms I have described in this thread be caused by cold bench and cold firing? Poor draw, chinmey cold while bell too hot, smoke back and stalling after 45-60min - all of these can be caused by poor draft, right? And a warm bench should improve it, especially in my design with so many turns in relatively short run. It isn't rhetorical question I would very much love if some one could confirm or deny.

I will keep firing, observing, changing, adding small things to see what they cause. There will be no wind on Sat and will be easiest to test for leaks

For the sake of learning, how far above roof can chimneys go safely? The insulated 250mm pipe I have used are only fixed to outside wall with stainless bands. Then every piece in the stack connects to another with a 'quick release' band.
My question is: how far up can this stack go safely without the need for extra bracing?
Mine runs along the highest point and so it may not be straightforwad to add support.
I asked this in the shop where we bought tubes but poeple there were clueless only showed us what to use to fix them to walls
2 years ago
Now we're talking!

I hope nobody reading this thread will think I am lazy, because I am far from that!
But Julian's posts are what I was hoping for

Bob, I am sure your ideas and logic are correct. But I could not stop believing that sollution must be in the parts I have touched I hope you know what I mean

Julian, I can't wait to try out 2 of your 3 suggestions (can't add another pipe until I get it). Actually, I pulled stove gasket and tried rocking drum as I wanted to replace it with another i have. I was more thinking the paint gasing or pin hole in the drum, but it is all the same to me I am not happy about the smell it gives off anyway. I thought it wouldn't because it is a stove paint at the end...

I don't know if you are barking at the wrong tree
I know I painted inside and out. And I said from the very beginning of this thread that drum was way hotter than before.
This is why I am so excited about your reply and about trying it out.
I was thinking how to do it... today tried fanning back of the drum. that's the hottest place (manifold is widest and bell is so close to vertical pipe I have there).
Heaters are not my thing and I don't know much about them. The Wisners' book was source of almost all I know.

Thanks, Julian!
2 years ago
Not at all!
Raising drum was one of suggested sollutions
Problem occured out of nowhere.
I painted barrel, replaced as it was (1/2'' lower it appeared) and changed one bridge brick.
Since then heater never has been the same... I mean, not anymore as it used to be.
2 years ago

julian Gerona wrote:Hey John, how about testing for leaks. Say start a fire and then seal all inlets and outlets. Smoke will find its way to the leak. With regards to vibration I see it as air speed inside as vibrating back and port. Why not add a length on the stack say 1 meter. Hot air will always have the tendency to go up. When its hot enough in the barrel the flue gas will tend to rise countering the downward flow. Thus at some point it becomes a tug of war between flue gas trying to go up in the drum and flue gas trying to go up the stack.

I see what you mean. It may be the case. As I implied earlier, sometimes I had a feeling hot air was trapped in bell and wouldnt go up the chimney.
I am still a bit afraid to add another 1m to the stack... it can blow real hard here. very strong gusts. I would not want it to crush fibrecement roofing...

I any case, should that be it, I have a good feeling about running this heater with bench all warm.
2 years ago
Hi, Julian

I'm afraid I don't have another legth of pipe. It would need to be insulated too, otherwise I have no means to secure it.
It has been brought up a couple of times. But no easily done here. Middle of nowhere. They don't deliver to PO box... I may have to go to Madrid soon so could look for maybe 0.5m at least...

I didn't know how to test for leaks. Your idea seems good. Have you actually tried it?
My problem is I am alone here now and it will take time to climb up the roof and back down. Will it not cause much problems? apart from some CO, I imagine?

Forgot to add
Bob asked about chimney temp.
When I said it was 'warm', I could hold my hand on lower part, by the 90deg elbow. And when I meant 'hot' it was impossible to touch it at all. I have no way to measure now. I plastered the only place thermometer would sit. When measured last year, it reached between 80-100C. cannot be more exact. I imagine it was this warm today, during the strong draw.
On the other hand, lowest part of chimney would be around 50c when not drawing well.

Where exactly do you mean, Julian, air would speed back and forth? Burn? Heat riser? duct? I am not sure if I understand

So in theory, we are talking about improving draw... warm bench should do it too, right?
Only asking as I want to reasure myself about the latest lead
2 years ago
I keep forgetting to add this
During the first firing today, with poor draw and panting, once flames started climbing up, fair amount of smoke was released (it did travel down though). I imagine it was due to lower temps in mid section of feed tube, as compare to burn chamber. This itself might have produced more charcoal and thus still weaker draw... Does it make sense?
In winter, I did have fire half way up feed tube, especially with a log inside. But have never seen any smoke like this. And flames always would point straight down.
I just hope that tomorrow, before most of you wake up, I will have good news
2 years ago
Thomas, it was only a joke that Bob is the only contributor. Well, fact is that he is the main figure, but I didn't mean it in a mean way

Peter, I'm sorry if I didn't descibe it properly. Didn't know how to put it well. Thing is, it isn't always like that. Sometimes slower pulses. But this morning it was the only time it scared me. To be honest, maybe it shook the rocket itself and fixed it for subsequent firing
Thanks for the link. I will read about it and maybe will figure something.

Peter, Bob
Since thses days I never get to fire it for longer than 60min, I only use twigs... max dia 3/4'', olive and almond prunings. They generally burn quickly. I have not seen anything unusual.
Actually, when pulsing, draft was very poor. When I re-fired later on the day, it amazed me because it pulled really strong. Really loud.
The reason for my second post earlier today was to share with you, guys, that the panting disappeared when draw improved. I have never experienced it before (pulsing) and from what Peter said here and on donkey32, I understood that stronger draw would actually escalate this pulsating. But it was gone altogether.

Bob, I am glad you take time to suggest all that. It's just that I don't want to go too deep, because it must be something so small that we (myself!) have overlooked.
That's why I have taken very seriously what you said earlier. My system may be on the edge of working or not. Maybe a small thing affects it. That's why I want to warm it up as in winter and hope it works. Meanwhile, I try to compare how it workes when I make small changes. Today I opened not only the manifold but also chimney cleanout. The latter cause fire to stall a little (and that was during the strong draw), so I realized that maybe hammering the tap on a little more or sealing it with aluminium tape will help. Then do the same with other cleanouts.
All has worked without those measures, but perhaps something small has changed...

When I commented about feed, I meant that I didn't necessarily do best job rebuilding the thing once I replaced bridge brick that cracked. Problem is, those bricks there have always been loose. One even kept sliding away, leaving 1/8'' gap where burn chamber starts. cracked bridge brick was loose too so not air tight at all. But the system worked great. That's why I didn't bother removing cob and insulation while redoing that. Even though I remembered that when last year I had similar problem (lazy flame at the far end of feed), redoing all brickwork (including heat riser and insulation) improved draft.

I wanted to remove the cowl. But since it was silicioned it (to stop it from rocking in VERY strong wind), I hesitated
Since you suggest so, I will do it tomorrow. I have almost 30C in the house and bell still warm so no need to fire this evening Top bench is warm and bottom is getting there too. So if my last theory about cold mass is to be true, I should have nice draw in the morninig! Fingers crossed. Maybe I won't have to touch the bell (although I already removed stove gasket due to curiousity

And please, ignore me next time I say that no one reads this thread it was my hopelessness laughing
2 years ago