Inner Burner tube: Cast Iron / Stainless steel

[biosolix]

Hello,

2006, I got a new PX21 equipped with a solid looking cast iron burner tube. Within 2 years,
the iron was deformed, the inner tube increased its diameter and contacted the outer steel tube. Both tubes could not be separated without flexing away pieces of the outer tube.
As a replacement, I now got a stainless steel pipe, which appears to better withstand the heat.
My question: Is this a new design?
I learned there where several of these "meltdowns", and they were related to bug in the iron mixture of the cast iron tube.
Looking at http://www.pelletsbilen.se/br-nnare-pel ... nor-3.html, the new one appears to be similar to "Innerrör Brännarkropp PX20 mod 2 "
Any idea of the history of these tubes ?

[Karla1]

They do a test with cast iron burner tube, but the alloy steel was hard to get a good level on, so I think they have turn back again to the stainless steel pipe for a longer life.

I think you got a better product now with the new pipe.

[Lager]

Hi,

My tube was also deformed, I was able to keep the outer tube though.
What happened was that the upper middle of the tube melted and bulged down.

As in your case my tube was less than two years old; so I got a free replacement. The replacement tube I got "seems" to be thicker than the previous one.

I got the same explanation as you that it was a material problem...
Mine was one of the first hundred tubes of cast iron, so maybe they have fixed the "quality problem" by now... time will tell.

[biosolix]

In the meantime I found this new stainless steel tube more closely described at
http://www.pelletsbilen.se/butiken/till ... t-kpl.html.
The steel type 253 MA SS 2368 is stable up to 1150°C, resists high temperature corrosion and erosion over a longer period. Sound like a good choice