Gábor Kertész

Update: I sealed the leaks around the oven, and got no alarms in the following burn. Got way too hot by night though.
I will switch to my woodstock with less BTUs for the time being. At least I get to use that as well.

The main bell was finished by the end of May and most of the bench by the end of August. Is that still not enough time withut regular fires?

I also checked the cold draft this morning. The chimney is fine, as is the bench but I saw nothing in the firebox and only the slightest at the port.

And as for now: the chimney is ready as well, the connection to it however (about a meter outside the yurt) is not yet insulated at all. The bench is also finished and I added a steel plate to the firebox as a door with the suggested openings for air intake.
We also lit two fires, and there was no backsmoking after the fire started up. There are two places leeking however. One was the cleaning port, which I managed to seel since, the other is the firebrick box of the oven, which I am still working on.

...

And my problem is that at the end of the second fire, as it was starting to quiet down, our CO alarm went off. We maanged to ventillate it out easily, but I have to think why that happened. I will check the draft when we get home today.
The uninsulated part of the chimney will be insulated ASAP.
And I will see to it that I seel the oven box as well.

What else should I check?
(I sure might have gone too close to the edge of the suggested parameters of CSA... I for now hope not however.)

Part III from this spring:

Part II from last autumn:

And hi again! "Soon" can be... weird.
Anyway here's the images I mentioned last time:

Hi everyone! I finally made progress again with the heater - I will post images as well soon. A question in the meantime: I understand that the top of the heater is partly held by T-profil steel pieces. Should I place kaowool under them as well for protection in the high heat above the riser? If so, how can I make the kaowool stay in place?

Thank you for the answers. I didn't realize the actual size difference between the designs because I noticed no ratios. (All of this wasn't meant to be a "but you told so", it was only meant to clear up my current or some potential later confusion.)

The real riser-to-minimum-bell CSA ratio is actually somewhat more than 5,1 as I designed with a 6 cm gap on both sides but ended up with 7,5 cm. I estimated during construction that it would still be within limits of the maximum total surface area. I will recheck more punctually but I can always make the bench a bit shorter if needed.
The bench CSA is also somewhat above 5x that of the riser.

Peter van den Berg wrote: How about the exit to the chimney? That is another potential friction area.

I have no detailed design yet but I intend to slowly narrow down to the 200 mm chimney flues I could get. The connection on the chimney is about 80 cm above the planned exit of the bench and about 50 cm away from it's end. I didn't yet decide whether to use two 90° turns on both the exit and the connection to the chimney or to make the entire length of the flue slanted and have 60° turns on both ends.

Peter van den Berg wrote:
I think this is it, better to ask first and build then?

Indeed it would be... Still far better to remake something then not to ask at all.

I calculated the size of the floor channel based on the 8,25% number from the Designs page on batchrocket.eu. A 60x60 steel duct would have a 9,98% internal cross section area of the riser. Would that cut it? (If not I will redesign accordingly of course.)
The stud being in the port is a great oversight on my part. At least it is easy to fix, but I remake the entire floor channel anyway. (Also by the Designs page the port of a 200 mm batch box should be 317 mm. Is that correct?)
I somehow missed the treshold. I will add one on the remade floor channel.

I built the riser into the rear of the firebox hence I wanted to make them level. I don't know why I didn't place at least fireclay mortar under there.

The total cross section area at the height of the gap is about 5,1 times the cross section area of the chimney.

Next pics and my first new question: the vertical piece of the floor channel is a bit off. Should I reweld it to make it straight? I think it ended up being far too short as well... I tried to base it off of the Mallorca core - but I realized only now that that core is 6"-es while mine is 8"-es large. How high should the vertical piece be?

And my second new question: I put a half inch kaowool sheet under the riser to make the base under it level. Will that cause cracks later on between the riser and the firebox? I have no desire to dismantle and rebuild the core but even less of a desire to finish a faulty heater...