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Post by stolzy on Aug 2, 2021 16:16:52 GMT
Oh …well if you decided to keep the oven I am sure it can be made to operate just fine! The problem is when a high mass casement is heated without any insulation the heat will not be evenly spread and the top of the dome will become much hotter than the the sides. Unfortunately this then causes different rates of expansion and can very easily cause cracks to form! Once a layer of insulation is applied, then the heat will be spread all around and start radiating back into the dome, in turn air is being drawn into the dome through the door opening. The air is then super heated and goes back out and up he chimney. That is the principle operation of a dome wood fired oven. It quite simply wont work efficiently without insulation. If I recall correctly one of the issues with this model is the small diameter chimney, however you can retro fit a larger 150mm chimney and even though the exit will still be 100mm the bigger flue will help a lot! Good luck with whatever happens . We've managed to avoid cracks so far, but with a (large and very smokey) fire going for 5 hours yesterday the top of the oven directly above the fire barely reached 300C (306C actually). I dream of getting the oven hot enough to have to worry about cracking the walls. I've started a Money Claim Online action (what used to be small claims court) against Vitcas Ltd. |
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fox
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Post by fox on Aug 2, 2021 16:25:36 GMT
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Post by stolzy on Aug 2, 2021 16:59:45 GMT
Yep, I'd seen that thread before. A different design and somewhat smaller oven than mine. the fire looks much more energetic than anything I've seen in mine. |
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fox
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Post by fox on Aug 2, 2021 17:57:50 GMT
Well if your claim is not successful, we are here to help you get it working.
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Post by truckcab79 on Aug 2, 2021 18:58:33 GMT
….and you’re certain that the flue isn’t closed?
It makes no sense that you can’t keep a fire going in it. Clearly they’ve sold many many of these without the same issue. It’s not like it needs to be doing something to help the fire. It’s just an empty shell. So long as you have dry fuel and air-flow it will burn.
Earlier comments about insulation are perfectly valid but they won’t stop you lighting a fire and getting it hot enough for pizzas. There are plenty of pizza ovens on the market with little or no insulation.
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Post by stolzy on Aug 3, 2021 5:10:15 GMT
….and you’re certain that the flue isn’t closed? It makes no sense that you can’t keep a fire going in it. Clearly they’ve sold many many of these without the same issue. It’s not like it needs to be doing something to help the fire. It’s just an empty shell. So long as you have dry fuel and air-flow it will burn. Earlier comments about insulation are perfectly valid but they won’t stop you lighting a fire and getting it hot enough for pizzas. There are plenty of pizza ovens on the market with little or no insulation. Absolutely certain. I asked them to put me in touch with one of the 'many' owners who have these working, but answer came there none.
My impression is that the oven isn't getting enough air because the inflow of air is choked by the smoke coming out.
This oven is actually sold without insulation and is intended to work without it. No insulation is provided, but it can be bought separately at extra cost.
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fox
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Post by fox on Aug 3, 2021 7:10:36 GMT
The vitcas site says ….
The dimensions are as follows:
External: 1,000mm wide x 1,720mm deep x 440mm high
Internal: 800mm wide x 1,400mm deep x 400mm high
So is the oven round inside with a 600 gallery or is it an oval shape?
So the traditional wood oven dome that I am used to working with would be exactly half a sphere ie 1000 wide and 500 high. The door opening hight is also a critical size of 63% of the dome hight.
Do you know the door opening dimensions?
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Post by stolzy on Aug 3, 2021 10:18:28 GMT
There's a slight misunderstanding, my oven is Vitcas Pompeii 100, not a 140. Consequently it is 1000 mm deep, not 1400mm. These ovens are based around a small, almost half-spherical shape. The larger ones (mine for example) have a 'straight' section in the middle so the oven is oval in shape. yet larger ones have two 'straight' sections making it even more oval.
The door/chimney section is the same on all their ovens (which might be the problem).
The door opening is 40 cm wide and 21.5 cm high at its maximum point.
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Post by truckcab79 on Aug 3, 2021 11:51:54 GMT
No it that it matters but I didn’t think it looked deep enough to be a 140. Shouldn’t make any difference though.
I appreciate that you’ve now used two different woods but have you checked the mosuture content of either one? You’d be unlucky to get two batches of wood that were not as ‘kiln dried’ as they should be but worth checking to rule it out.
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fox
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Post by fox on Aug 3, 2021 13:03:24 GMT
I found the dimensions although I cant really understand exactly where they are measuring from, however I assume that the Vitcas Pompeii 100 Is in fact what I would call a 80cm oven because it has an 800mm internal diameter, that would be classed by many as a small oven but in fact is a very sensible size oven!
They say the internal hight is 400mm and the external hight is 440mm suggesting the oven thickness is 40mm however the external diameter is 1000 making the sides 100mm thick … that is extremely unlikely?
The normal thickness of a high mass cast dome is between 50-65 mm.
Anyway with a 400 high dome the entrance should be around 400 wide and 252 mm high.
My own cast ovens are made to a very similar size 32”( 820mm)) and use a 430 x 260 opening.
So the opening is a little low.
I have no way of knowing how the trasisson from the inner dome into the chimney gallery is shaped as this is another critical area and of course you have an uninsulated 100mm chimney!
Them we have the insulation issue… I know I am just repeating myself but assuming the dome is 40mm thick, you can not expect to captivate that much heat as it will just pass through the mass into the air and in fact even Vitcas recommend 7 meters of ceramic fibre matting to cover the dome.
I have built somewhere in the region of 30-35 ovens but I have never tried firing one without insulation so to be absolutely honest I really don't know how hot you could get the inside of a new oven without insulation?
If it were possible to see the oven, I am sure any obvious issue would become clear but from a armchair it all a bit speculative and subjective!
However as truckcap points out it is unlikely Vitcas would sell a product that simply does not work.
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Post by stolzy on Aug 3, 2021 14:47:06 GMT
I found the dimensions although I cant really understand exactly where they are measuring from, however I assume that the Vitcas Pompeii 100 Is in fact what I would call a 80cm oven because it has an 800mm internal diameter, that would be classed by many as a small oven but in fact is a very sensible size oven! They say the internal hight is 400mm and the external hight is 440mm suggesting the oven thickness is 40mm however the external diameter is 1000 making the sides 100mm thick … that is extremely unlikely? The normal thickness of a high mass cast dome is between 50-65 mm. Anyway with a 400 high dome the entrance should be around 400 wide and 252 mm high. My own cast ovens are made to a very similar size 32”( 820mm)) and use a 430 x 260 opening. So the opening is a little low. I have no way of knowing how the trasisson from the inner dome into the chimney gallery is shaped as this is another critical area and of course you have an uninsulated 100mm chimney! Them we have the insulation issue… I know I am just repeating myself but assuming the dome is 40mm thick, you can not expect to captivate that much heat as it will just pass through the mass into the air and in fact even Vitcas recommend 7 meters of ceramic fibre matting to cover the dome. I have built somewhere in the region of 30-35 ovens but I have never tried firing one without insulation so to be absolutely honest I really don't know how hot you could get the inside of a new oven without insulation? If it were possible to see the oven, I am sure any obvious issue would become clear but from a armchair it all a bit speculative and subjective! However as truckcap points out it is unlikely Vitcas would sell a product that simply does not work. So far as the insulation is concerned, I was told to fire the oven several times without it. Vitacas (even today by phone and on their website) confirm that the oven will cook pizza perfectly well without the insulation. I now seem to have the attention of someone senior at Vitcas (rather than the sales team who seem to double up as 'support'). Amazing what a bit of gentle legal action can do that mere dozens and dozens of phone call don't. We'll see where this goes. |
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Post by truckcab79 on Aug 3, 2021 18:51:08 GMT
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Post by stolzy on Aug 4, 2021 9:26:15 GMT
I've tried three different lots of kiln-dried hardwood. I guess it's possible that all three were faulty, but it seems unlikely. I don't have facilities to test the wood. I never thought that it would be necessary. To no one's great surprise yesterday's promised delivery of the extended flue from Vitcas failed to materialise. Maybe it will today. |
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Post by truckcab79 on Aug 4, 2021 9:37:44 GMT
Yea. Very unlikely. Worth picking one up for future deliveries regardless of your issues now. They’re only about £10-15 off eBay or Amazon.
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Post by stolzy on Aug 4, 2021 11:56:19 GMT
Yea. Very unlikely. Worth picking one up for future deliveries regardless of your issues now. They’re only about £10-15 off eBay or Amazon. Yep, one on it's way already. |
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